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McCarthy DM, Spencer TJ, Bhide PG. Preclinical Models of Attention Deficit Hyperactivity Disorder: Neurobiology, Drug Discovery, and Beyond. J Atten Disord 2024; 28:880-894. [PMID: 38084074 DOI: 10.1177/10870547231215286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
OBJECTIVE We offer an overview of ADHD research using mouse models of nicotine exposure. METHOD Nicotine exposure of C57BL/6 or Swiss Webster mice occurred during prenatal period only or during the prenatal and the pre-weaning periods. Behavioral, neuroanatomical and neurotransmitter assays were used to investigate neurobiological mechanisms of ADHD and discover candidate ADHD medications. RESULTS Our studies show that norbinaltorphimine, a selective kappa opioid receptor antagonist is a candidate novel non-stimulant ADHD treatment and that a combination of methylphenidate and naltrexone has abuse deterrent potential with therapeutic benefits for ADHD. Other studies showed transgenerational transmission of ADHD-associated behavioral traits and demonstrated that interactions between untreated ADHD and repeated mild traumatic brain injury produced behavioral traits not associated with either condition alone. CONCLUSION Preclinical models contribute to novel insights into ADHD neurobiology and are valuable tools for drug discovery and translation to benefit humans with ADHD.
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Affiliation(s)
| | - Thomas J Spencer
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Pradeep G Bhide
- Florida State University College of Medicine, Tallahassee, FL, USA
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Shram MJ, Setnik B, Webster L, Guenther S, Mickle TC, Braeckman R, Kanski J, Martin A, Kelsh D, Vince BD, Barrett AC. Oral, intranasal, and intravenous abuse potential of serdexmethylphenidate, a novel prodrug of d-methylphenidate. Curr Med Res Opin 2022; 38:1237-1250. [PMID: 35570699 DOI: 10.1080/03007995.2022.2076474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Serdexmethylphenidate (SDX) chloride (Cl) is a novel prodrug of d-methylphenidate (d-MPH). These studies evaluated the abuse potential of SDX Cl when administered orally, intranasally (IN), and intravenously (IV). METHODS Three randomized, double-blind, placebo- and active-controlled crossover studies were conducted in recreational drug users to evaluate the abuse-related effects of oral SDX (120 and 240 mg) vs. extended-release (ER) d-MPH (80 mg) and phentermine (60 mg); IN SDX (80 mg) vs. d-MPH (40 mg), and IV SDX (30 mg) vs. d-MPH (15 mg). Abuse-related subjective measures, pharmacokinetics, and safety were assessed. RESULTS The primary endpoint of maximum (Emax) Drug Liking (DL) (0-100-point scale) was significantly higher following d-MPH vs. placebo, validating the studies. In the oral study, DL Emax was significantly higher following 80 mg ER d-MPH (Emax = 81.5) than 120 mg SDX (Emax = 62.8, p < .001) and 240 mg SDX (Emax = 63.8, p = .006); and following 60 mg phentermine (Emax = 80.2) than 120 mg SDX (p = .0195), but not 240 mg SDX (p = .0665). DL Emax scores were significantly higher following IN d-MPH vs SDX (Emax = 93.2 vs. 71.0, p < .0001) and following IV d-MPH vs. SDX (Emax = 84.3 vs. 56.6, p = .001). Intravenous SDX was non-inferior to placebo (p = .001) for DL Emax. Secondary endpoints (e.g. Take Drug Again) were generally consistent with the primary endpoint. Maximal and overall d-MPH exposure was lower for SDX than d-MPH for all routes. Adverse events typical of stimulants were more frequent with d-MPH than SDX. CONCLUSIONS These findings indicate that the novel d-MPH prodrug, SDX, has lower abuse potential than d-MPH and support its classification as a C-IV controlled substance.
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Affiliation(s)
- Megan J Shram
- Altreos Research Partners, Inc, Toronto, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| | - Beatrice Setnik
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
- Altasciences, Laval, Canada
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Qian Y, Markowitz JS. Prediction of Carboxylesterase 1-mediated In Vivo Drug Interaction between Methylphenidate and Cannabinoids using Static and Physiologically Based Pharmacokinetic Models. Drug Metab Dispos 2022; 50:968-979. [PMID: 35512806 PMCID: PMC11022897 DOI: 10.1124/dmd.121.000823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/12/2022] [Indexed: 11/22/2022] Open
Abstract
The use of cannabis products has increased substantially. Cannabis products have been perceived and investigated as potential treatments for attention-deficit/hyperactivity disorder (ADHD). Accordingly, co-administration of cannabis products and methylphenidate (MPH), a first-line medication for ADHD, is possible. Oral MPH undergoes extensive presystemic metabolism by carboxylesterase 1 (CES1), a hepatic enzyme which can be inhibited by two prominent cannabinoids, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). This prompts further investigation into the likelihood of clinical interactions between MPH and these two cannabinoids through CES1 inhibition. In the present study, inhibition parameters were obtained from a human liver S9 system and then incorporated into static and physiologically-based pharmacokinetic (PBPK) models for prediction of potential clinical significance. The inhibition of MPH hydrolysis by THC and CBD was reversible, with estimated unbound inhibition constants (Ki,u) of 0.031 and 0.091 µM, respectively. The static model predicted a mild increase in MPH exposure by concurrent THC (34%) and CBD (94%) from smoking a cannabis cigarette and ingestion of prescriptive CBD, respectively. PBPK models suggested no significant interactions between single doses of MPH and CBD (2.5 - 10 mg/kg) when administered simultaneously, while a mild interaction (area under drug concentration-time curve increased by up to 55% and maximum concentration by up to 45%) is likely if multiple doses of CBD (10 mg/kg twice daily) are administered. In conclusion, the pharmacokinetic disposition of MPH can be potentially influenced by THC and CBD under certain clinical scenarios. Whether the magnitude of predicted interactions translates into clinically relevant outcomes requires verification in an appropriately designed clinical study. SIGNIFICANCE STATEMENT: This work demonstrated a potential mechanism of drug-drug interactions between methylphenidate (MPH) and two major cannabinoids (Δ9-tetrahydrocannabinol [THC] and cannabidiol [CBD]) not previously reported. We predicted a mild interaction between MPH and THC when the cannabinoid exposure occurred via cannabis smoking. Mild interactions between MPH and CBD were predicted with multiple oral administrations of CBD.
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Affiliation(s)
- Yuli Qian
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, Florida
| | - John S Markowitz
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, Florida
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Strand MC, Mørland J, Slørdal L, Riedel B, Innerdal C, Aamo T, Mathisrud G, Vindenes V. Conversion factors for assessment of driving impairment after exposure to multiple benzodiazepines/z-hypnotics or opioids. Forensic Sci Int 2017; 281:29-36. [PMID: 29101905 DOI: 10.1016/j.forsciint.2017.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 09/06/2017] [Accepted: 10/11/2017] [Indexed: 11/18/2022]
Abstract
AIMS Norway has introduced legal concentration limits in blood for 28 non-alcohol drugs in driving under the influence cases. As of 2016 this legislation also regulates the assessment of combined effects of multiple benzodiazepines and opioids. We herein describe the employed methodology for the equivalence tables for concentrations of benzodiazepines/z-hypnotics and opioids implemented in the Norwegian Road Traffic Act. METHODS Legislative limits corresponding to impairment at blood alcohol concentrations (BAC) of 0.02%, 0.05% and 0.12% were established for 15 different benzodiazepines and opioids. This was based on a concept of a linear relationship between blood drug concentration and impairment in drug naïve users. Concentration ratios between these drugs were used to establish conversion factors and calculate net impairment using diazepam and morphine equivalents. RESULTS Conversion factors were established for 14 benzodiazepines/z-hypnotics (alprazolam, bromazepam, clobazam, clonazepam, etizolam, flunitrazepam, lorazepam, nitrazepam, nordiazepam, oxazepam, phenazepam, temazepam, zolpidem and zopiclone) and two opioids (methadone and oxycodone). CONCLUSIONS Conversion factors to calculate diazepam and morphine equivalents for benzodiazepines/z-hypnotics and selected opioids, respectively, have been operative in the Norwegian Road Traffic Act as of February 2016. Calculated equivalents can be applied by the courts to meter out sanctions.
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Affiliation(s)
| | - Jørg Mørland
- Norwegian Institute of Public Health, Division of Health Data and Digitalization, Oslo, Norway.
| | - Lars Slørdal
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway; Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.
| | - Bettina Riedel
- University of Bergen, Faculty of Medicine and Dentistry, Department of Clinical Science, Bergen, Norway; Haukeland University Hospital, Laboratory of Clinical Biochemistry, Bergen, Norway.
| | | | - Trond Aamo
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.
| | - Grete Mathisrud
- Norwegian Ministry of Transport and Communications, Department of Public Roads and Traffic Safety, Oslo, Norway.
| | - Vigdis Vindenes
- Oslo University Hospital, Department of Forensic Medicine, Oslo, Norway; Center of Drug and Addiction Research, Faculty of Medicine, University of Oslo, Norway.
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Chermá MD, Josefsson M, Rydberg I, Woxler P, Trygg T, Hollertz O, Gustafsson PA. Methylphenidate for Treating ADHD: A Naturalistic Clinical Study of Methylphenidate Blood Concentrations in Children and Adults With Optimized Dosage. Eur J Drug Metab Pharmacokinet 2017; 42:295-307. [PMID: 27220743 PMCID: PMC5340830 DOI: 10.1007/s13318-016-0346-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Background Methylphenidate (MPH), along with behavioral and psychosocial interventions, is the first-line medication to treat attention-deficit hyperactivity disorder (ADHD) in Sweden. The dose of MPH for good symptom control differs between patients. However, studies of MPH concentration measurement in ADHD treatment are limited. Objective To describe blood and oral fluid (OF) concentrations of MPH after administration of medication in patients with well-adjusted MPH treatment for ADHD, and to identify the most suitable matrix for accurate MPH concentration during treatment. Methods Patients were recruited from Child and Adolescent Psychiatry (CAP), General Psychiatry (GP), and the Department of Dependency (DD). Blood and OF samples were collected in the morning before MPH administration as well as 1 and 6 h after administration of the prescribed morning dose of MPH. Results Fifty-nine patients aged between 9 and 69 years, 76 % males. The daily dose of MPH varied from 18 to 180 mg, but the median daily dose per body weight was similar, approximately 1.0 mg/kg body weight. The median MPH concentration in blood 1 and 6 h after the morning dose was 5.4 and 9.3 ng/mL, respectively. Highly variable OF-to-blood ratios for MPH were found at all time points for all three groups. Conclusions Weight is a reliable clinical parameter for optimal dose titration. Otherwise, MPH blood concentration might be used for individual dose optimization and for monitoring of the prescribed dose. Relying only on the outcome in OF cannot be recommended for evaluation of accurate MPH concentrations for treatment monitoring.
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Affiliation(s)
- Maria D Chermá
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden. .,Department of Clinical Pharmacology and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
| | - Martin Josefsson
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden.,Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Irene Rydberg
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Per Woxler
- Department of Dependency, Linköping University Hospital, Linköping, Sweden
| | - Tomas Trygg
- Department of Dependency, Linköping University Hospital, Linköping, Sweden
| | - Olle Hollertz
- Department of General Psychiatry, Västervik Hospital, Västervik, Sweden
| | - Per A Gustafsson
- Center for Social and Affective Neuroscience Department of Clinical and Experimental Medicine and Department of Child and Adolescent Psychiatry, Linköping University, Linköping, Sweden
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Abstract
INTRODUCTION Attention-deficit/hyperactivity disorder (ADHD) is a complex neurobehavioral disorder affecting millions of patients worldwide. Effective treatments have been available for more than 60 years in the form of immediate-release (IR) stimulants However, stimulants have a high risk for abuse and are associated with adverse effects Including elevated blood pressure and heart rate, insomnia and decreased appetite. IR formulations also require multiple daily dosing. The search for improved safety, tolerability and convenience has led to the development of multiple extended-release (ER) stimulant and non-stimulant formulations. Areas covered: Adverse effects of (ER) products including amphetamine, methylphenidate, clonidine and guanfacine will be reviewed and their significance discussed. Expert opinion: Limitations of currently marketed medications have led to the search for drugs with efficacy comparable to ER stimulants and a more favorable adverse event profile. Several are in development, but their potential utility is not yet known. Current research is also focused on finding specific genetic defects in patients with ADHD. Exciting progress has been made with the identification of mGluR receptor defects in some patients. However because of the heterogeneity of the disorder, effective targeted treatments for the majority of patients with ADHD does not appear likely in the near future.
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Affiliation(s)
- Ann Childress
- a Center for Psychiatry and Behavioral Medicine, Inc ., 7351 Prairie Falcon Road, Las Vegas , Nevada , United States
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Li L, Wang Y, Uppoor RS, Mehta MU, Farchione T, Mathis MV, Zhu H. Exposure-response analyses of blood pressure and heart rate changes for methylphenidate in healthy adults. J Pharmacokinet Pharmacodyn 2017; 44:245-262. [PMID: 28214989 DOI: 10.1007/s10928-017-9513-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/09/2017] [Indexed: 11/30/2022]
Abstract
The aim of the study was to evaluate the exposure-response (E-R) relationships of blood pressure (BP) and heart rate (HR) changes in healthy adults taking methylphenidate (MPH). Intensive time profiles of BP and HR from healthy adults in placebo and MPH treatment arms of seven clinical trials from the FDA internal database were utilized for this analysis. The analysis model contains a circadian component for placebo effect and an E-R component to describe drug effect. Internal validation was performed using goodness-of-fit plots and visual predictive check. A meta-database based on a systemic literature search was constructed and used for external validation of the developed models. We found that circadian models could quantify the time profiles of BP/HR in placebo arms. Linear models could describe the correlations between MPH concentrations, and BP/HR changes. The BP and HR changes were highly dependent on the shapes of MPH pharmacokinetic (PK) profiles without an apparent time delay. MPH has the greatest effect on HR, followed by systolic BP, and diastolic BP. Internal validation revealed that the developed models could adequately describe the circadian rhythms of HR and BP in placebo arms and the E-R relationships of MPH. External validation showed the models had good predictive capability of the literature data. In conclusion, the developed models adequately characterized the circadian rhythm and the MPH induced effects on BP and HR. The changes in BP and HR were highly correlated with MPH blood levels with no apparent delay. The time courses of BP and HR are similar to the MPH PK profiles. As a result, the immediate-release formulation may yield larger maximum BP and HR effect than the extended-release formulation under similar dose.
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Affiliation(s)
- Liang Li
- Division of Clinical Pharmacology I, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Yaning Wang
- Division of Pharmacometrics, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Ramana S Uppoor
- Division of Clinical Pharmacology I, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Mehul U Mehta
- Division of Clinical Pharmacology I, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Tiffany Farchione
- Division of Psychiatry Products, Office of Drug Evaluation I, Office of New Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Mitchell V Mathis
- Division of Psychiatry Products, Office of Drug Evaluation I, Office of New Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
| | - Hao Zhu
- Division of Clinical Pharmacology I, Office of Clinical Pharmacology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
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Abstract
As the first drug to see widespread use for the treatment of attention deficit hyperactivity disorder (ADHD), methylphenidate was the forerunner and catalyst to the modern era of rapidly increasing diagnosis, treatment, and medication development for this condition. During its often controversial history, it has variously elucidated the importance of dopamine signaling in memory and attention, provoked concerns about pharmaceutical cognitive enhancement, driven innovation in controlled-release technologies and enantiospecific therapeutics, and stimulated debate about the impact of pharmaceutical sales techniques on the practice of medicine. In this Review, we will illustrate the history and importance of methylphenidate to ADHD treatment and neuroscience in general, as well as provide key information about its synthesis, structure-activity relationship, pharmacological activity, metabolism, manufacturing, FDA-approved indications, and adverse effects.
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Affiliation(s)
- Cody J. Wenthur
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
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Koblan KS, Hopkins SC, Sarma K, Gallina N, Jin F, Levy-Cooperman N, Schoedel KA, Loebel A. Assessment of human abuse potential of dasotraline compared to methylphenidate and placebo in recreational stimulant users. Drug Alcohol Depend 2016; 159:26-34. [PMID: 26794682 DOI: 10.1016/j.drugalcdep.2015.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 10/22/2022]
Abstract
AIMS The aim of this study was to evaluate the abuse potential of dasotraline, a novel dopamine and norepinephrine reuptake inhibitor with slow absorption (tmax, 10-12h) and elimination (t1/2=47-77 h) that is in development for the treatment of attention deficit hyperactivity disorder (ADHD). METHODS Recreational stimulant users (N=48) who had specific experience with cocaine, and who were able to distinguish methylphenidate (60 mg) versus placebo in a qualification session, were randomized, in a 6-period, double-blind, crossover design, to receive single doses of dasotraline 8 mg, 16 mg, and 36 mg, methylphenidate (MPH) 40 mg and 80 mg, and placebo. The primary endpoint was the Drug Liking Visual Analog Scale (VAS) score at the time of peak effect (Emax). RESULTS There were no significant differences between the 3 doses of dasotraline and placebo on the drug liking VAS at Emax, and on most secondary endpoints. Both doses of MPH had significantly higher VAS-drug liking scores at Emax relative to both placebo (P<0.001 for all comparisons) and dasotraline 8 mg (P<0.001), 16 mg (P<0.001) and 36 mg (P<0.01). The increase in heart rate for MPH and dasotraline 36 mg showed a time-course that closely matched subject-rated measures such as Any Effects VAS. CONCLUSIONS In this study, dasotraline was found to have low potential for abuse, which may be, in part, related to its established pharmacokinetics (PK) profile, which is characterized by slow absorption and gradual elimination.
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Affiliation(s)
- K S Koblan
- Sunovion Pharmaceuticals Inc., Marlborough, MA, USA.
| | - S C Hopkins
- Sunovion Pharmaceuticals Inc., Marlborough, MA, USA
| | - K Sarma
- Sunovion Pharmaceuticals Inc., Marlborough, MA, USA
| | - N Gallina
- Sunovion Pharmaceuticals Inc., Marlborough, MA, USA
| | - F Jin
- Sunovion Pharmaceuticals Inc., Marlborough, MA, USA
| | | | | | - A Loebel
- Sunovion Pharmaceuticals Inc., Marlborough, MA, USA
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Rasmussen L, Zoëga H, Hallas J, Pottegård A. Deviant patterns of methylphenidate use in adults: a Danish nationwide registry-based drug utilization study. Pharmacoepidemiol Drug Saf 2015; 24:1189-96. [PMID: 26278467 DOI: 10.1002/pds.3852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 06/29/2015] [Accepted: 07/15/2015] [Indexed: 11/11/2022]
Abstract
PURPOSE Several survey studies have documented misuse of methylphenidate defined as the use of non-prescribed methylphenidate or use different from what was prescribed. We aimed to identify and characterize adults with deviant patterns of methylphenidate use in Denmark during 2007-2012. Further, we aimed to identify risk factors associated with deviant patterns of use. METHODS Based on individual-level prescription data, new users of methylphenidate were followed for one year after filling their first prescription on methylphenidate. Adult patients were identified with deviant patterns of use if they had ≥4 different prescribers and filled ≥1095 defined daily doses of methylphenidate during the year of follow-up. Risk factors were estimated by using logistic regression. RESULTS Among 20 829 new users of methylphenidate, we identified 82 (0.39%) patients displaying deviant patterns of use. Characteristics associated with deviant patterns of use included an initial prescription for extended-release methylphenidate (OR2 4.35), age 25-49 years at first prescription (OR2 2.49), general practitioners or hospital doctors as initial prescribers (OR2 3.06 and OR2 4.07) and prior use of drugs used in addictive disorders (OR2 2.08) or opioids (OR2 1.75). Sensitivity analyses revealed that the number of different prescribers alone does not seem to effectively identify deviant users of methylphenidate. CONCLUSION We have identified characteristics associated with deviant patterns of methylphenidate use. Our results do not allow us to conclude if deviant users truly represent medical misusers.
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Affiliation(s)
- Lotte Rasmussen
- Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense C, Denmark
| | - Helga Zoëga
- Centre of Public Health Sciences, Faculty of Medicine, University of Iceland, Reykjavík, Iceland
| | - Jesper Hallas
- Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense C, Denmark
| | - Anton Pottegård
- Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense C, Denmark
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Pérez de los Cobos J, Siñol N, Pérez V, Trujols J. Pharmacological and clinical dilemmas of prescribing in co-morbid adult attention-deficit/hyperactivity disorder and addiction. Br J Clin Pharmacol 2014; 77:337-56. [PMID: 23216449 DOI: 10.1111/bcp.12045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 11/20/2012] [Indexed: 12/21/2022] Open
Abstract
The present article reviews whether available efficacy and safety data support the pharmacological treatment of adult attention-deficit/hyperactivity disorder (ADHD) in patients with concurrent substance use disorders (SUD). Arguments for and against treating adult ADHD with active SUD are discussed. Findings from 19 large open studies and controlled clinical trials show that the use of atomoxetine or extended-release methylphenidate formulations, together with psychological therapy, yield promising though inconclusive results about short term efficacy of these drugs in the treatment of adult ADHD in patients with SUD and no other severe mental disorders. However, the efficacy of these drugs is scant or lacking for treating concurrent SUD. No serious safety issues have been associated with these drugs in patients with co-morbid SUD-ADHD, given their low risk of abuse and favourable side effect and drug-drug interaction profile. The decision to treat adult ADHD in the context of active SUD depends on various factors, some directly related to SUD-ADHD co-morbidity (e.g. degree of diagnostic uncertainty for ADHD) and other factors related to the clinical expertise of the medical staff and availability of adequate resources (e.g. the means to monitor compliance with pharmacological treatment). Our recommendation is that clinical decisions be individualized and based on a careful analysis of the advantages and disadvantages of pharmacological treatment for ADHD on a case-by-case basis in the context of active SUD.
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Affiliation(s)
- José Pérez de los Cobos
- Unitat de Conductes Addictives, Servei de Psiquiatria, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomèdica Sant Pau (IIB Sant Pau), Barcelona, Spain
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Yang X, Morris SM, Gearhart JM, Ruark CD, Paule MG, Slikker W, Mattison DR, Vitiello B, Twaddle NC, Doerge DR, Young JF, Fisher JW. Development of a physiologically based model to describe the pharmacokinetics of methylphenidate in juvenile and adult humans and nonhuman primates. PLoS One 2014; 9:e106101. [PMID: 25184666 PMCID: PMC4153582 DOI: 10.1371/journal.pone.0106101] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/28/2014] [Indexed: 11/18/2022] Open
Abstract
The widespread usage of methylphenidate (MPH) in the pediatric population has received considerable attention due to its potential effect on child development. For the first time a physiologically based pharmacokinetic (PBPK) model has been developed in juvenile and adult humans and nonhuman primates to quantitatively evaluate species- and age-dependent enantiomer specific pharmacokinetics of MPH and its primary metabolite ritalinic acid. The PBPK model was first calibrated in adult humans using in vitro enzyme kinetic data of MPH enantiomers, together with plasma and urine pharmacokinetic data with MPH in adult humans. Metabolism of MPH in the small intestine was assumed to account for the low oral bioavailability of MPH. Due to lack of information, model development for children and juvenile and adult nonhuman primates primarily relied on intra- and interspecies extrapolation using allometric scaling. The juvenile monkeys appear to metabolize MPH more rapidly than adult monkeys and humans, both adults and children. Model prediction performance is comparable between juvenile monkeys and children, with average root mean squared error values of 4.1 and 2.1, providing scientific basis for interspecies extrapolation of toxicity findings. Model estimated human equivalent doses in children that achieve similar internal dose metrics to those associated with pubertal delays in juvenile monkeys were found to be close to the therapeutic doses of MPH used in pediatric patients. This computational analysis suggests that continued pharmacovigilance assessment is prudent for the safe use of MPH.
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Affiliation(s)
- Xiaoxia Yang
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
- * E-mail:
| | - Suzanne M. Morris
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - Jeffery M. Gearhart
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Wright-Patterson Air Force Base, Ohio, United States of America
| | - Christopher D. Ruark
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Wright-Patterson Air Force Base, Ohio, United States of America
| | - Merle G. Paule
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - William Slikker
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - Donald R. Mattison
- Risk Sciences International, Ottawa, Ontario, Canada
- University of Ottawa, Ottawa, Ontario, Canada
| | - Benedetto Vitiello
- National Institute of Mental Health, Bethesda, Maryland, United States of America
| | - Nathan C. Twaddle
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - Daniel R. Doerge
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - John F. Young
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - Jeffrey W. Fisher
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, United States of America
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Mead AN. Appropriate experimental approaches for predicting abuse potential and addictive qualities in preclinical drug discovery. Expert Opin Drug Discov 2014; 9:1281-91. [PMID: 25176123 DOI: 10.1517/17460441.2014.956077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Drug abuse is an increasing social and public health issue, putting the onus on drug developers and regulatory agencies to ensure that the abuse potential of novel drugs is adequately assessed prior to product launch. AREAS COVERED This review summarizes the core preclinical data that frequently contribute to building an understanding of abuse potential for a new molecular entity, in addition to highlighting models that can provide increased resolution regarding the level of risk. Second, an important distinction between abuse potential and addiction potential is drawn, with comments on how preclinical models can inform on each. EXPERT OPINION While the currently adopted preclinical models possess strong predictive validity, there are areas for future refinement and research. These areas include a more refined use of self-administration models to assess relative reinforcement; and the need for open innovation in pursuing improvements. There is also the need for careful scientifically driven application of models rather than a standardization of methodologies, and the need to explore the opportunities that may exist for enhancing the value of physical dependence and withdrawal studies by focusing on withdrawal-induced drug seeking, rather than broad symptomology.
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Affiliation(s)
- Andy N Mead
- Global Safety Pharmacology, Drug Safety Research and Development, Pfizer Worldwide Research and Development , Eastern Point Road, MS 8274-1232, Groton, CT 06340 , USA
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Human abuse liability evaluation of CNS stimulant drugs. Neuropharmacology 2014; 87:81-90. [PMID: 24793872 DOI: 10.1016/j.neuropharm.2014.04.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/01/2014] [Accepted: 04/16/2014] [Indexed: 01/16/2023]
Abstract
Psychoactive drugs that increase alertness, attention and concentration and energy, while also elevating mood, heart rate and blood pressure are referred to as stimulants. Despite some overlapping similarities, stimulants cannot be easily categorized by their chemical structure, mechanism of action, receptor binding profile, effects on monoamine uptake, behavioral pharmacology (e.g., effects on locomotion, temperature, and blood pressure), therapeutic indication or efficacy. Because of their abuse liability, a pre-market assessment of abuse potential is required for drugs that show stimulant properties; this review article focuses on the clinical aspects of this evaluation. This includes clinical trial adverse events, evidence of diversion or tampering, overdoses and the results of a human abuse potential study. While there are different types of human experimental studies that can be employed to evaluate stimulant abuse potential (e.g., drug discrimination, self-administration), only the human abuse potential study and clinical trial adverse event data are required for drug approval. The principal advances that have improved human abuse potential studies include using study enrichment strategies (pharmacologic qualification), larger sample sizes, better selection of endpoints and measurement strategies and more carefully considered interpretation of data. Because of the methodological advances, comparisons of newer studies with historical data is problematic and may contribute to a biased regulatory framework for the evaluation of newer stimulant-like drugs, such as A2 antagonists. This article is part of the Special Issue entitled 'CNS Stimulants'.
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Ramos-Quiroga JA, Corominas M, Castells X, Bosch R, Casas M. OROS methylphenidate for the treatment of adults with attention-deficit/hyperactivity disorder. Expert Rev Neurother 2014; 9:1121-31. [DOI: 10.1586/ern.09.65] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Maldonado R. Comparison of the pharmacokinetics and clinical efficacy of new extended-release formulations of methylphenidate. Expert Opin Drug Metab Toxicol 2013; 9:1001-14. [DOI: 10.1517/17425255.2013.786041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Long-acting stimulants for treatment of attention-deficit/hyperactivity disorder: a focus on extended-release formulations and the prodrug lisdexamfetamine dimesylate to address continuing clinical challenges. ACTA ACUST UNITED AC 2013; 5:249-65. [PMID: 23564273 PMCID: PMC3751218 DOI: 10.1007/s12402-013-0106-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/16/2013] [Indexed: 11/25/2022]
Abstract
Individuals with attention-deficit/hyperactivity disorder (ADHD) show pervasive impairments across family, peer, and school or work functioning that may extend throughout the day. Psychostimulants are highly effective medications for the treatment of ADHD, and the development of long-acting stimulant formulations has greatly expanded the treatment options for individuals with ADHD. Strategies for the formulation of long-acting stimulants include the combination of immediate-release and delayed-release beads, and an osmotic-release oral system. A recent development is the availability of the first prodrug stimulant, lisdexamfetamine dimesylate (LDX). LDX itself is inactive but is cleaved enzymatically, primarily in the bloodstream, to release d-amphetamine (d-AMP). Several clinical trials have demonstrated that long-acting stimulants are effective in reducing ADHD symptoms compared with placebo. Analog classroom and simulated adult workplace environment studies have shown that long-acting stimulants produce symptom reduction for at least 12 h. Long-acting stimulants exhibit similar tolerability and safety profiles to short-acting equivalents. While variations in gastric pH and motility can alter the availability and absorption of stimulants released from long-acting formulations, the systemic exposure to d-AMP following LDX administration is unlikely to be affected by gastrointestinal conditions. Long-acting formulations may also improve adherence and lower abuse potential compared with their short-acting counterparts. The development of long-acting stimulants provides physicians with an increased range of medication options to help tailor treatment for individuals with ADHD.
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Stein JS, Johnson PS, Renda CR, Smits RR, Liston KJ, Shahan TA, Madden GJ. Early and prolonged exposure to reward delay: effects on impulsive choice and alcohol self-administration in male rats. Exp Clin Psychopharmacol 2013; 21:172-80. [PMID: 23356729 PMCID: PMC3686290 DOI: 10.1037/a0031245] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Naturally occurring impulsive choice has been found to positively predict alcohol consumption in rats. However, the extent to which experimental manipulation of impulsive choice may modify alcohol consumption remains unclear. In the present study, we sought to: (a) train low levels of impulsive choice in rats using early, prolonged exposure to reward delay, and (b) determine the effects of this manipulation on subsequent alcohol consumption. During a prolonged training regimen, three groups of male, adolescent Long-Evans rats (21-22 days old at intake) responded on a single lever for food rewards delivered after either a progressively increasing delay, a fixed delay, or no delay. Posttests of impulsive choice were conducted, as was an evaluation of alcohol consumption using a limited-access, two-bottle test. Following delay-exposure training, both groups of delay-exposed rats made significantly fewer impulsive choices than did rats in the no-delay group. In addition, fixed-delay rats consumed significantly more alcohol during daily, 30-min sessions than no-delay rats. Possible mechanisms of these effects are discussed, as is the significance of these findings to nonhuman models of addiction.
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Affiliation(s)
- Jeffrey S Stein
- Department of Psychology, Utah State University, 2810 Old Main Hill, Logan, UT 84322, USA.
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Mizuno K, Yoneda T, Komi M, Hirai T, Watanabe Y, Tomoda A. Osmotic release oral system-methylphenidate improves neural activity during low reward processing in children and adolescents with attention-deficit/hyperactivity disorder. NEUROIMAGE-CLINICAL 2013; 2:366-76. [PMID: 24179790 PMCID: PMC3777787 DOI: 10.1016/j.nicl.2013.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 02/16/2013] [Accepted: 03/06/2013] [Indexed: 11/16/2022]
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is neurobehavioral disorder characterized by inattention, hyperactivity/impulsivity and impaired reward system function, such as delay aversion and low reward sensitivity. The pharmacological treatment for ADHD includes methylphenidate (MPH), or osmotic release oral system-MPH (OROS-MPH), which increases extrasynaptic dopamine and noradrenaline levels by blocking their reuptake. Although previous functional magnetic resonance imaging (fMRI) studies revealed that acute treatment with MPH alters activation of the nucleus accumbens during delay aversion in children and adolescents with ADHD, the effects a relatively long period of OROS-MPH treatment on delay aversion as well as reward sensitivity remain unclear. Thus, we evaluated brain activation with fMRI during a reward sensitivity paradigm that consists of high monetary reward and low monetary reward conditions before and after a 3-month treatment with OROS-MPH in 17 children and adolescents with ADHD (mean age, 13.3 ± 2.2) and 17 age- and sex-matched healthy controls (mean age, 13.0 ± 1.9). We found that before treatment there was decreased activation of the nucleus accumbens and thalamus in patients with ADHD during only the low monetary reward condition, which was improved to same level as those of the healthy controls after the treatment. The observed change in brain activity was associated with improved ADHD symptom scores, which were derived from Japanese versions of the ADHD rating scale-IV. These results suggest that treatment with OROS-MPH for a relatively long period is effective in controlling reward sensitivity in children and adolescents with ADHD. Attention deficit/hyperactivity disorder (ADHD) has low reward sensitivity. Activity in thalamus and nucleus accumbens was decreased in low monetary reward. Osmotic release oral system-methylphenidate (OROS-MPH) is a medication for ADHD. Brain activity and ADHD symptoms were improved by 3-month treatment with OROS-MPH. OROS-MPH treatment for long periods may change brain activity of pediatric ADHD.
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Affiliation(s)
- Kei Mizuno
- Molecular Probe Dynamics Laboratory, RIKEN Center for Molecular Imaging Science, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe City, Hyogo 650-0047, Japan ; Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka City, Osaka 545-8585, Japan
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Weisler RH, Childress AC. Treating attention-deficit/hyperactivity disorder in adults: focus on once-daily medications. Prim Care Companion CNS Disord 2012; 13:11r01168. [PMID: 22454805 DOI: 10.4088/pcc.11r01168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/15/2011] [Indexed: 10/15/2022] Open
Abstract
OBJECTIVE To review the efficacy, safety, and abuse liability of approved treatments in adults with attention-deficit/hyperactivity disorder (ADHD), with a focus on once-daily medications. DATA SOURCES PubMed was searched for relevant studies/reviews in English from 2002 to 2011 on adult ADHD treatments. STUDY SELECTION Keywords used in the search were ADHD, adults, and treatment. Limits included only clinical trials, meta-analyses, randomized controlled trials, and reviews including adults (aged ≥ 19 years). DATA EXTRACTION Selection criteria returned 471 publications. Retrieved studies were excluded if they primarily focused on children, treatments not indicated for ADHD, or ADHD and comorbid conditions. DATA SYNTHESIS An epidemiologic survey revealed that 10.9% of adults identified with ADHD had received treatment during the prior 12 months. Treatments for ADHD in adults include pharmacologic and nonpharmacologic options. US Food and Drug Administration-approved long-acting stimulants and a nonstimulant with proven efficacy and safety profiles have been developed and include osmotic-release oral system methylphenidate hydrochloride (OROS-methylphenidate), extended-release dexmethylphenidate hydrochloride, mixed amphetamine salts extended release (MAS-XR), the nonstimulant atomoxetine hydrochloride, and the prodrug lisdexamfetamine dimesylate. Long-acting stimulants differ in formulation characteristics used to achieve extended release, with OROS-methylphenidate employing an osmotic-release technology, extended-release dexmethylphenidate hydrochloride and MAS-XR using pH-dependent beads, and lisdexamfetamine dimesylate using prodrug technology. These features variably affect pharmacokinetic characteristics, duration of action, and abuse liability. While all long-acting medications have varied pharmacokinetic features, mechanism of action, and duration of effect, all are generally efficacious and safety profiles are similar. CONCLUSION Approved long-acting treatments in adults with ADHD were effective in improving symptoms and were generally well tolerated.
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Affiliation(s)
- Richard H Weisler
- Department of Psychiatry, University of North Carolina, Chapel Hill School of Medicine, Chapel Hill, and Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina (Dr Weisler); and Department of Family Practice, Center for Psychiatry and Behavioral Medicine, Inc, Las Vegas, Nevada, and Department of Psychiatry at the University of Nevada School of Medicine, Reno (Dr Childress)
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The use of medication against attention deficit/hyperactivity disorder in Denmark: a drug use study from a patient perspective. Eur J Clin Pharmacol 2012; 69:589-98. [DOI: 10.1007/s00228-012-1344-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 06/21/2012] [Indexed: 11/27/2022]
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Shram MJ, Quinn AM, Chen N, Faulknor J, Luong D, Sellers EM, Endrenyi L. Differences in the in vitro and in vivo pharmacokinetic profiles of once-daily modified-release methylphenidate formulations in Canada: examination of current bioequivalence criteria. Clin Ther 2012; 34:1170-81. [PMID: 22512898 DOI: 10.1016/j.clinthera.2012.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 02/11/2012] [Accepted: 02/16/2012] [Indexed: 11/26/2022]
Abstract
BACKGROUND Current Canadian bioequivalence criteria rely on rate and extent of drug exposure, that is, C(max) and AUC. In the case of complex modified-release formulations, these criteria may not address pharmacokinetic differences with potential therapeutic and tolerability implications. OBJECTIVE This study was performed to characterize in vitro dissolution and in vivo pharmacokinetic profiles of three modified-release formulations of methylphenidate (MPH) marketed in Canada, two of which meet the criteria for assuming bioequivalence as defined by Health Canada: MPH extended-release (ER-C) and osmotic controlled-release oral-delivery-system (OROS-MPH). METHODS In vitro dissolution tests were performed using 54-mg OROS-MPH, 54-mg MPH ER-C, and 20-mg MPH sustained-release (SR) tablets. In vivo pharmacokinetics of single oral doses of 54 mg OROS-MPH, 54 mg MPH ER-C, and 60 mg MPH-SR were evaluated in an open-label, randomized, crossover study in healthy subjects. Plasma samples were collected up to 24 hours after administration of the drug. RESULTS In vitro dose-corrected release profiles of MPH ER-C and MPH-SR tablets were similar (<10% difference), whereas OROS-MPH exhibited a profile distinct from that of the other formulations. Twenty-four subjects completed the pharmacokinetic study and were included in the analyses. Analysis of C(max) and AUC of MPH showed that OROS-MPH and MPH ER-C met the criteria for assumed bioequivalence according to Health Canada guidelines. However, partial AUCs exhibited significant differences between the two formulations, which were supported by ratios of MPH concentrations over time. Comparison of MPH ER-C with MPH-SR (dose corrected) also satisfied bioequivalence criteria. CONCLUSIONS The pharmacokinetic data suggest that in vitro and in vivo profiles of OROS-MPH and MPH ER-C are distinct. However, using traditional criteria for bioequivalence, MPH ER-C would be assumed bioequivalent to both OROS-MPH and MPH-SR. Inclusion of partial AUCs as additional criteria could aid in ensuring therapeutic equivalence. ClinicalTrials.gov identifier: NCT01118702.
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Levi MS, Divine B, Hanig JP, Doerge DR, Vanlandingham MM, George NI, Twaddle NC, Bowyer JF. A comparison of methylphenidate-, amphetamine-, and methamphetamine-induced hyperthermia and neurotoxicity in male Sprague–Dawley rats during the waking (lights off) cycle. Neurotoxicol Teratol 2012; 34:253-62. [DOI: 10.1016/j.ntt.2012.01.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 01/12/2012] [Accepted: 01/14/2012] [Indexed: 10/14/2022]
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Carrey N, Wilkinson M. A review of psychostimulant-induced neuroadaptation in developing animals. Neurosci Bull 2011; 27:197-214. [PMID: 21614102 DOI: 10.1007/s12264-011-1004-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The effects of clinically relevant doses of commonly prescribed stimulants methylphenidate (MPH), d-amphetamine (d-AMPH), and dl-AMPH or mixed amphetamine salts (MAS) such as Adderall, on short- and long-term gene neuroadaptations in developing animals have not been widely investigated. In the present review, the effects of oral stimulant administration were compared with those of the subcutaneous or intra-peritoneal route. A selective set of studies between 1979 and 2010, which incorporated in their design developmental period, clinically relevant doses of stimulants, and repeated daily doses were reviewed. These studies indicate that neuroadaptation to chronic stimulants includes blunting of stimulated immediate early gene expression, sensitivity of younger (prepubertal) brain to smaller dosages of stimulants, and the persistence of some effects, especially behavioral neuroadaptations, into adulthood. In addition, oral amphetamines (MAS) have more profound effects than does oral MPH. Further animal developmental studies are required to understand potential long-term neuroadaptations to low, daily oral doses of stimulants. Implications for clinical practice were also discussed.
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Affiliation(s)
- Normand Carrey
- Department of Psychiatry, IWK Health Centre, Halifax, Nova Scotia, Canada.
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Rizkallah E, Legault L, Pampoulova T, Lévesque S, Bélanger M, Stavro K, Chiasson JP, Potvin S. A case report of Concerta misuse in a patient with comorbid substance use disorder and attention deficit hyperactivity disorder. Am J Addict 2011; 20:478-9. [PMID: 21838849 DOI: 10.1111/j.1521-0391.2011.00158.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Normandin MD, Schiffer WK, Morris ED. A linear model for estimation of neurotransmitter response profiles from dynamic PET data. Neuroimage 2011; 59:2689-99. [PMID: 21767654 DOI: 10.1016/j.neuroimage.2011.07.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 05/26/2011] [Accepted: 07/01/2011] [Indexed: 11/26/2022] Open
Abstract
The parametric ntPET model (p-ntPET) estimates the kinetics of neurotransmitter release from dynamic PET data with receptor-ligand radiotracers. Here we introduce a linearization (lp-ntPET) that is computationally efficient and can be applied to single scan data. lp-ntPET employs a non-invasive reference region input function and extends the LSRRM of Alpert et al. (2003) using basis functions to characterize the time course of neurotransmitter activation. In simulation studies, the temporal precision of neurotransmitter profiles estimated by lp-ntPET was similar to that of p-ntPET (standard deviation ~3 min for responses early in the scan) while computation time was reduced by several orders of magnitude. Violations of model assumptions such as activation-induced changes in regional blood flow or specific binding in the reference tissue have negligible effects on lp-ntPET performance. Application of the lp-ntPET method is demonstrated on [11C]raclopride data acquired in rats receiving methamphetamine, which yielded estimated response functions that were in good agreement with simultaneous microdialysis measurements of extracellular dopamine concentration. These results demonstrate that lp-ntPET is a computationally efficient, linear variant of ntPET that can be applied to PET data from single or multiple scan designs to estimate the time course of neurotransmitter activation.
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Affiliation(s)
- Marc D Normandin
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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Josefsson M, Rydberg I. Determination of methylphenidate and ritalinic acid in blood, plasma and oral fluid from adolescents and adults using protein precipitation and liquid chromatography tandem mass spectrometry—A method applied on clinical and forensic investigations. J Pharm Biomed Anal 2011; 55:1050-9. [DOI: 10.1016/j.jpba.2011.03.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 11/30/2022]
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Abstract
OBJECTIVE To review the literature describing impairments in educational, occupational, and social functioning in adults with attention-deficit/hyperactivity disorder (ADHD), current treatment trends, and factors that may influence the abuse potential of long-acting medications used to treat ADHD in adults. METHODS A MEDLINE search was conducted to identify articles relating to functional impairments and treatment options for adults with ADHD, as well as the abuse potential of ADHD medications. RESULTS ADHD is one of the most common psychiatric behavioral disorders in children, and its symptoms have been shown to persist into adulthood. Symptoms of ADHD may occur at home, school, work, or in social situations, and symptom occurrence in these different settings can have a profound negative impact for adults with ADHD. Impairments in educational, occupational, and social functioning in adults with ADHD have been described and are summarized in this review article. Although long-acting medications are more frequently prescribed for children with ADHD than short-acting medications, adults with ADHD are equally likely to be treated with short- and long-acting medications. While all medications used to treat ADHD in adults have potential for abuse, there are a number of factors that may contribute to a lower potential for abuse for long-acting agents compared with immediate-release medications. CONCLUSION Impairments from ADHD can be chronic and persistent and they can affect daily educational, occupational, and personal functioning. Adults, in particular, have responsibilities that can extend into the late evening hours so that clinicians need to consider medication duration of action when selecting a pharmacotherapy intervention for adults with ADHD.
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McBurnett K, Starr HL. OROS methylphenidate hydrochloride for adult patients with attention deficit/hyperactivity disorder. Expert Opin Pharmacother 2011; 12:315-24. [DOI: 10.1517/14656566.2011.546058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Volkow ND, Wang GJ, Fowler JS, Tomasi D, Telang F, Baler R. Addiction: decreased reward sensitivity and increased expectation sensitivity conspire to overwhelm the brain's control circuit. Bioessays 2010; 32:748-55. [PMID: 20730946 DOI: 10.1002/bies.201000042] [Citation(s) in RCA: 318] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Based on brain imaging findings, we present a model according to which addiction emerges as an imbalance in the information processing and integration among various brain circuits and functions. The dysfunctions reflect (a) decreased sensitivity of reward circuits, (b) enhanced sensitivity of memory circuits to conditioned expectations to drugs and drug cues, stress reactivity, and (c) negative mood, and a weakened control circuit. Although initial experimentation with a drug of abuse is largely a voluntary behavior, continued drug use can eventually impair neuronal circuits in the brain that are involved in free will, turning drug use into an automatic compulsive behavior. The ability of addictive drugs to co-opt neurotransmitter signals between neurons (including dopamine, glutamate, and GABA) modifies the function of different neuronal circuits, which begin to falter at different stages of an addiction trajectory. Upon exposure to the drug, drug cues or stress this results in unrestrained hyperactivation of the motivation/drive circuit that results in the compulsive drug intake that characterizes addiction.
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Affiliation(s)
- Nora D Volkow
- National Institute on Drug Abuse, NIH, Bethesda, MD 20892, USA.
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Stoops WW, Poole MM, Vansickel AR, Hays KA, Glaser PEA, Rush CR. Methylphenidate increases choice of cigarettes over money. Nicotine Tob Res 2010; 13:29-33. [PMID: 21059817 DOI: 10.1093/ntr/ntq198] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Stimulants increase cigarette smoking in the naturalistic environment and laboratory. The effects of methylphenidate on a 9-trial, discrete cigarette versus money ($0.25) choice task were tested to elucidate the mechanisms underlying stimulant-induced increases in smoking. METHODS Eleven participants who reported smoking 10-20 cigarettes/day completed the study. Four doses of methylphenidate (0, 10, 20, and 40 mg) were administered across 5 experimental sessions, with placebo administered twice. One hour following medication administration and at 30-min intervals thereafter, participants chose between smoking a cigarette and receiving US$0.25. The primary behavioral outcome measure was number of cigarette choices. RESULTS Methylphenidate increased the number of cigarette choices over money. Puffs per session and carbon monoxide levels increased significantly and caloric intake decreased significantly following methylphenidate administration relative to placebo. CONCLUSIONS The results of this study suggest that methylphenidate increases the relative reinforcing efficacy of cigarette smoking. Stimulant use may thus be an important consideration for individuals attempting to quit smoking.
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Affiliation(s)
- William W Stoops
- Department of Behavioral Science, University of Kentucky College of Medicine, 140 Medical Behavioral Science Building, Lexington, KY 40536-0086, USA
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Brams M, Moon E, Pucci M, López FA. Duration of effect of oral long-acting stimulant medications for ADHD throughout the day. Curr Med Res Opin 2010; 26:1809-25. [PMID: 20491612 DOI: 10.1185/03007995.2010.488553] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To examine duration of efficacy in long-acting stimulant treatment of attention-deficit/hyperactivity disorder (ADHD) in clinical trials using analog classroom protocols. RESEARCH DESIGN AND METHODS Published reports of clinical trials examining duration of medication efficacy using analog classroom protocols were identified in a systematic literature search of PubMed, BIOSYS, and EMBASE, through June 2009 using combinations of terms: attention-deficit/hyperactivity disorder, ADHD, attention-deficit disorder with hyperactivity, stimulant, methylphenidate (MPH), amphetamine, laboratory school or classroom, analog classroom, math test, and Permanent Product Measure of Performance (PERMP). Reports of short-acting, nonoral or nonstimulant formulations, or inadequate data on duration of efficacy were excluded. MAIN OUTCOME MEASURES Main outcomes examined were PERMP scores for number of math problems attempted (PERMP-A) and correctly answered (PERMP-C) based on a standard 10-minute math test given at regular intervals during the postdose period. RESULTS Fifteen trials were included in the analysis. All except one trial in adults (18-55 years) were conducted in children with ADHD (6-15 years) and employed randomized, double- or single-blind, placebo-controlled designs. Duration of efficacy, based on PERMP-A/-C scores (vs. placebo), ranged from 8 hours with long-acting MPH to 14 hours with lisdexamfetamine dimesylate; most formulations exerted therapeutic effects for 12 hours after a single morning dose. Duration of efficacy assessment may be limited by duration of observation (12 hours postdose for most studies). Outcomes may have been influenced by differences in study designs, population characteristics, lack of comparable, equivalent dosages of different extended-release stimulants, and limited ability to extrapolate safety and tolerability from short-term studies to long-term clinical use. Results from cross-study comparisons must be interpreted with caution. CONCLUSIONS Most long-acting stimulants exerted beneficial effects on ADHD symptoms for up to 12 hours as measured by the PERMP; the longest duration of efficacy versus placebo was seen with lisdexamfetamine dimesylate (14 hours postdose).
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Schoedel KA, Meier D, Chakraborty B, Manniche PM, Sellers EM. Subjective and Objective Effects of the Novel Triple Reuptake Inhibitor Tesofensine in Recreational Stimulant Users. Clin Pharmacol Ther 2010; 88:69-78. [DOI: 10.1038/clpt.2010.67] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Intermittent methylphenidate during adolescent development produces locomotor hyperactivity and an enhanced response to cocaine compared to continuous treatment in rats. Pharmacol Biochem Behav 2010; 96:166-74. [PMID: 20460134 DOI: 10.1016/j.pbb.2010.04.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 04/18/2010] [Accepted: 04/30/2010] [Indexed: 11/21/2022]
Abstract
The consequences of chronic methylphenidate (MPH) administration in adolescents for the treatment of attention-deficit/hyperactivity disorder (ADHD) remain to be fully understood. Studies in rats indicate that the pharmacokinetics of psychostimulant administration can powerfully influence the behavioral and neural consequences of chronic treatment. The purpose of the present study was to assess the effects of intermittent (0.8 or 1.6mg/kg, s.c., twice daily) versus continuous (1.6 or 3.2mg/kg/day via osmotic minipump) MP administration across four weeks of adolescent development in rats. Results indicate that intermittent treatment produced hyperactivity in a novel open field and increased sensitivity to both the reinforcing and locomotor-activating effects of cocaine. In contrast, continuous MPH resulted in a hypoactive response to the novel open field and a reduced sensitivity to both operant and non-contingent cocaine. To the extent that the continuous release condition models the sustained-release formulations utilized in human ADHD treatment, we interpret these data to indicate that sustained-release formulations are less likely to advance a risk of subsequent substance abuse.
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Evaluation of the abuse potential of extended release hydromorphone versus immediate release hydromorphone. J Clin Psychopharmacol 2010; 30:25-33. [PMID: 20075644 DOI: 10.1097/jcp.0b013e3181c8f088] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Immediate release (IR) hydromorphone has experienced significant misuse and abuse. An extended release (ER) hydromorphone formulation has been developed to provide sustained pain relief and may reduce the likelihood for abuse by delaying absorption. In this double-blind, placebo-controlled, randomized, 2-part crossover study, the abuse potential of single oral doses of hydromorphone ER (intact: 16-, 32-, and 64-mg; milled: 8-mg) was compared with 8-mg hydromorphone IR and placebo. After drug administration, subjects with a history of recreational opioid use completed a series of assessments, including subjective effects visual analog scales (eg, drug liking) and Addiction Research Center Inventory With Cole Modification, at several timepoints up to 48 hours postdose. Independent of formulation, maximum at-the-moment drug liking was higher for hydromorphone versus placebo. Maximum drug liking occurred earlier and was higher for 8-mg IR versus 16-mg ER but similar to 32- and 64-mg ER. Most positive effects were lower after 16-mg ER compared with other doses, including 8-mg IR. Bad drug effects were higher for hydromorphone ER, particularly the 64-mg dose. Milled 8-mg ER produced similar subjective effects to 8-mg IR. Comparison of scores after administration of 8-mg IR on 2 separate occasions showed that most assessments exhibited good test-retest reliability, although some scores declined marginally between test and retest. Delayed onset of good drug effects and prominent bad drug effects of hydromorphone ER suggest that, when administered intact, this formulation may have lower abuse potential than hydromorphone IR.
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Moen MD, Keam SJ. Dexmethylphenidate extended release: a review of its use in the treatment of attention-deficit hyperactivity disorder. CNS Drugs 2009; 23:1057-83. [PMID: 19958043 DOI: 10.2165/11201140-000000000-00000] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Dexmethylphenidate extended release (XR) [Focalin XR] is a CNS stimulant indicated for the treatment of attention-deficit hyperactivity disorder (ADHD) in patients aged > or = 6 years. Dexmethylphenidate contains the d-threo-enantiomer of methylphenidate. Dexmethylphenidate XR capsules have a bimodal release profile, which mimics two doses of dexmethylphenidate immediate release (IR) given 4 hours apart, and allows once-daily administration. Once-daily dexmethylphenidate XR was effective and generally well tolerated in the treatment of ADHD in children, adolescents and adults in placebo-controlled trials. Improvements in ADHD symptoms were significantly greater for dexmethylphenidate XR versus placebo throughout the day, from as early as 0.5 hours after drug administration up to 11-12 hours after administration. Furthermore, dexmethylphenidate XR showed greater efficacy than osmotic release oral system (OROS) methylphenidate over the first half of the laboratory classroom day in crossover trials; however, assessments late in the day (10-12 hours post-dose) favoured OROS methylphenidate. The once-daily administration regimen with dexmethylphenidate XR avoids the need for a midday dose to be administered at school; administration options are extended in that the contents of the dexmethylphenidate XR capsule can be sprinkled on apple sauce for patients unable to swallow the capsule whole. Although dexmethylphenidate XR is a controlled substance in the US, this formulation appears to have a low risk of abuse or misuse. Thus, dexmethylphenidate XR extends the range of first-line pharmacological treatment options for children, adolescents or adults with ADHD, particularly for patients who require a rapid onset and prolonged duration of action, including children who require a reduction in ADHD symptoms throughout the school day.
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Affiliation(s)
- Marit D Moen
- Adis, a Wolters Kluwer Business, Auckland, New Zealand.
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Janknegt R, Faber A, Rodrigues Pereira R, Kalverdijk LJ. InforMatrix for attention deficit hyperactivity disorder. Expert Opin Pharmacother 2009; 10:755-72. [PMID: 19351226 DOI: 10.1517/14656560902765769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The purpose of this review is to facilitate discussion on drug selection for the treatment of ADHD by using only clinically relevant selection criteria and providing an up-to-date overview. The InforMatrix method was used to select drugs to treat attention deficit hyperactivity disorder (ADHD). The following selection criteria were applied: clinical efficacy, safety, tolerability, ease of use, applicability, and cost. The drugs approved for ADHD in the Netherlands were included in the analysis, namely: atomoxetine, immediate-release methylphenidate, and various formulations of slow-release methylphenidate (Concerta, Equasym and Medikinet). Most studies are of limited quality, duration, and size. In one study, Concerta was more effective than atomoxetine. Although no relevant differences were seen in other comparative studies, the clinical experience with atomoxetine is still limited and unexpected toxicity cannot be excluded; few studies have been published with Equasym and Medikinet. No major differences were seen in general tolerability between the drugs. The ease of use of immediate-release methylphenidate is less than for the other drugs. The acquisition cost of immediate-release methylphenidate is considerably lower than that of the slow-release formulations. Atomoxetine is the most expensive drug. The InforMatrix program is available in an interactive format. It enables the user to judge both the importance of the selection criteria and the properties of each therapeutic option per criterion on the basis of his or her own personal expertise and/or the present document.
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Affiliation(s)
- Robert Janknegt
- Hospital Pharmacist, Clinical Pharmacologist Maasland Ziekenhuis, Postbus, Sittard, The Netherlands.
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Ghaffari M. The abuse potential of medications for attention-deficit/hyperactivity disorder: Recent advances in our understanding. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s12618-009-0005-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Patrick KS, Straughn AB, Perkins JS, González MA. Evolution of stimulants to treat ADHD: transdermal methylphenidate. Hum Psychopharmacol 2009; 24:1-17. [PMID: 19051222 PMCID: PMC2629554 DOI: 10.1002/hup.992] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE The following comprehensive review describes the evolution of stimulant drug formulations used in the treatment of attention-deficit/hyperactivity disorder (ADHD). Emphasis is placed on the basic and clinical pharmacology of the dl-methylphenidate (MPH) transdermal system (MTS). METHODS The pharmacokinetic and pharmacodynamic literature pertaining to MPH and amphetamine enantiomers was reviewed in the context of ADHD therapy and MTS as a treatment option. RESULTS MTS incorporates MPH into an adhesive monolithic matrix, using the free base form of the drug to facilitate transdermal absorption. MTS technology minimizes contact dermatitis by eliminating to need for percutaneous penetration enhancers. After a lag time of approximately 2 h, plasma concentrations of the therapeutic d-MPH isomer become detectable, then continuously rise over the course of the recommended 9 h wear time. Concentrations of l-MPH typically attain 40-50% that of d-MPH (vs. 1-2% following oral MPH). Unauthorized MTS removal poses some misuse liability and over 50% of MTS drug content remains in the discarded system. CONCLUSIONS While liquid or chewable MPH formulations overcome potential swallowing difficulties, as do sprinkled once-daily extended-release (ER) MPH products, only MTS addresses swallowing difficulties while also offering a flexible individualized MPH exposure time in a once-daily MPH regimen.
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Affiliation(s)
- Kennerly S. Patrick
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA,Correspondence to: K. S. Patrick, 280 Calhoun St., QF221A, Medical University of South Carolina, Charleston, SC 29425−0742, USA. Tel: (843) 792−8429. Fax: (843) 792−1617. E-mail:
| | - Arthur B. Straughn
- Department of Pharmaceutical Sciences, University of Tennessee, Memphis, Tennessee, USA
| | - Jeb S. Perkins
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
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Volkow ND, Fowler JS, Wang GJ, Baler R, Telang F. Imaging dopamine's role in drug abuse and addiction. Neuropharmacology 2008; 56 Suppl 1:3-8. [PMID: 18617195 DOI: 10.1016/j.neuropharm.2008.05.022] [Citation(s) in RCA: 575] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 05/06/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
Abstract
Dopamine is involved in drug reinforcement but its role in addiction is less clear. Here we describe PET imaging studies that investigate dopamine's involvement in drug abuse in the human brain. In humans the reinforcing effects of drugs are associated with large and fast increases in extracellular dopamine, which mimic those induced by physiological dopamine cell firing but are more intense and protracted. Since dopamine cells fire in response to salient stimuli, supraphysiological activation by drugs is experienced as highly salient (driving attention, arousal, conditioned learning and motivation) and with repeated drug use may raise the thresholds required for dopamine cell activation and signaling. Indeed, imaging studies show that drug abusers have marked decreases in dopamine D2 receptors and in dopamine release. This decrease in dopamine function is associated with reduced regional activity in orbitofrontal cortex (involved in salience attribution; its disruption results in compulsive behaviors), cingulate gyrus (involved in inhibitory control; its disruption results in impulsivity) and dorsolateral prefrontal cortex (involved in executive function; its disruption results in impaired regulation of intentional actions). In parallel, conditioning triggered by drugs leads to enhanced dopamine signaling when exposed to conditioned cues, which then drives the motivation to procure the drug in part by activation of prefrontal and striatal regions. These findings implicate deficits in dopamine activity-inked with prefrontal and striatal deregulation-in the loss of control and compulsive drug intake that results when the addicted person takes the drugs or is exposed to conditioned cues. The decreased dopamine function in addicted individuals also reduces their sensitivity to natural reinforcers. Therapeutic interventions aimed at restoring brain dopaminergic tone and activity of cortical projection regions could improve prefrontal function, enhance inhibitory control and interfere with impulsivity and compulsive drug administration while helping to motivate the addicted person to engage in non-drug related behaviors.
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Affiliation(s)
- N D Volkow
- National Institute on Drug Abuse, NIH, Bethesda, MD 20892, USA.
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