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Carbonaro TM, Nguyen V, Forster MJ, Gatch MB, Prokai L. Carisoprodol pharmacokinetics and distribution in the nucleus accumbens correlates with behavioral effects in rats independent from its metabolism to meprobamate. Neuropharmacology 2020; 174:108152. [PMID: 32479814 DOI: 10.1016/j.neuropharm.2020.108152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 04/29/2020] [Accepted: 05/18/2020] [Indexed: 10/24/2022]
Abstract
Carisoprodol (Soma®) is a centrally-acting skeletal-muscle relaxant frequently prescribed for treatment of acute musculoskeletal conditions. Carisoprodol's mechanism of action is unclear and is often ascribed to that of its active metabolite, meprobamate. The purpose of this study was to ascertain whether carisoprodol directly produces behavioral effects, or whether metabolism to meprobamate via cytochrome P450 (CYP450) enzymatic reaction is necessary. Rats were trained to discriminate carisoprodol (100 mg/kg) to assess time course and whether a CYP450 inhibitor (cimetidine) administered for 4 days would alter the discriminative effects of carisoprodol. Additionally, pharmacokinetics of carisoprodol and meprobamate with and without co-administration of cimetidine were assessed via in vivo microdialysis combined with liquid-chromatography-tandem mass spectrometry from blood and nucleus accumbens (NAc). The time course of the discriminative-stimulus effects of carisoprodol closely matched the time course of the levels of carisoprodol in blood and NAc, but did not match the time course of meprobamate. Administration of cimetidine increased levels of carisoprodol and decreased levels of meprobamate consistent with its interfering with metabolism of carisoprodol to meprobamate. However, cimetidine failed to alter the discriminative-stimulus effects of carisoprodol. Carisoprodol penetrated into brain tissue and directly produced behavioral effects without being metabolized to meprobamate. These findings indicate that understanding the mechanism of action of carisoprodol independently of meprobamate will be necessary to determine the validity of its clinical uses.
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Affiliation(s)
- Theresa M Carbonaro
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107-2699, USA
| | - Vien Nguyen
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107-2699, USA
| | - Michael J Forster
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107-2699, USA
| | - Michael B Gatch
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107-2699, USA
| | - Laszlo Prokai
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107-2699, USA.
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Abstract
This review examines literature on the efficacy and abuse potential of carisoprodol, makes recommendations for use of this agent in the hospital setting, and outlines applicable federal and state regulations. A Medline search using key words and MeSH terms was conducted. In addition, International Pharmaceutical Abstracts (1970–2002), Current Contents (1996–2002), Cochrane Database of Systematic Reviews (1999–2002), and Psych Info (1872–2002) were searched for relevant literature. Articles cited in the bibliographies produced by these searches were included in the review. A Web of Science search was conducted for all citations found in all the searches. Pain is a common physical symptom in patients with musculoskeletal problems, and pharmacologic therapy is often combined with nonpharmacologic measures to treat the pain etiology and symptomatology. Skeletal muscle relaxants (SMRs) and nonsteroidal anti-inflammatory drugs (NSAIDs) represent the most common drug therapy choices in patients with mild-to-moderate somatic pain. Carisoprodol (Soma) is an SMR that has a poorly defined mechanism of action and a high potential for abuse. This literature review produced little evidence to support the use of carisoprodol in pain control. The research also showed that patients with a history of previous substance abuse are more likely to abuse this drug; thus carisoprodol does not meet safety and efficacy standards and should be removed from the market. At the very least, states should reschedule carisoprodol as a schedule IV controlled substance to minimize chronic misuse and abuse. If carisprodol is listed in hospital formularies, it should be handled as a controlled substance regardless of its federal status. Alternative sedatives (eg, phenobarbital) should be used to manage patients experiencing carisoprodol withdrawal symptoms.
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Affiliation(s)
- Lisa Anne Boothby
- Drug Information, Columbus Regional Drug Information Center, Columbus Regional Healthcare System
| | - Paul L. Doering
- Drug Information and Pharmacy Resource Center, Distinguished Service, college of Pharmacy, University of Florida
| | - Randy C. Hatton
- Drug Information and Pharmacy Resource Center, Shands at the University of Florida and College of Pharmacy, University of Florida
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Abstract
Soma (Carisoprodol) is N-isopropyl-2 methyl-2-propyl-1,3-propanediol dicarbamate; a commonly prescribed, centrally acting skeletal muscle relaxant. Neuroleptic malignant syndrome (NMS) is a potentially life-threatening adverse effect of antipsychotic agents. Although diagnostic criteria for NMS have been established, it should be recognized that atypical presentations occur and more flexible diagnostic criteria than currently mandated, may be warranted. We wish to report a postoperative case of bilateral knee replacement who presented with carisoprodol (Soma) withdrawal resembling NMS that was a diagnostic dilemma. Subsequently, it was successfully treated with oral baclofen in absence of sodium dantrolene.
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Affiliation(s)
- Gunchan Paul
- Department of Critical Care Medicine, Dayanand Medical College, Ludhiana, Punjab, India
| | - Gautam L Parshotam
- Department of Critical Care Medicine, Dayanand Medical College, Ludhiana, Punjab, India
| | - Rajneesh Garg
- Department of Orthopedics, Dayanand Medical College, Ludhiana, Punjab, India
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Gatch MB, Nguyen JD, Carbonaro T, Forster MJ. Carisoprodol tolerance and precipitated withdrawal. Drug Alcohol Depend 2012; 123:29-34. [PMID: 22055010 PMCID: PMC3288484 DOI: 10.1016/j.drugalcdep.2011.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Revised: 10/11/2011] [Accepted: 10/13/2011] [Indexed: 11/26/2022]
Abstract
AIMS Carisoprodol is a muscle relaxant that acts at the GABA(A) receptor. Concerns about the abuse liability of carisoprodol are increasing, but evidence that carisoprodol produces tolerance and a significant withdrawal syndrome has yet to be established. The purpose of the current study was to determine if repeated administration of carisoprodol produces tolerance and withdrawal signs in a mouse model. METHODS Carisoprodol (0, 100, 200, 300, or 500 mg/kg bid, i.p.) was administered to Swiss-Webster mice for 4 days and loss-of-righting reflex was measured 20-30 min following each administration. On the fourth day, bemegride (20 mg/kg), flumazenil (20 mg/kg), or vehicle was administered following carisoprodol and withdrawal signs were measured. Separate groups of mice receiving the same treatment regimen and dose range were tested for spontaneous withdrawal at 6, 12 and 24 h after the last dose of carisoprodol. RESULTS The righting reflex was dose-dependently impaired following the first administration of carisoprodol. A 75-100% decrease in the magnitude of the impairment occurred over the four days of exposure, indicating the development of tolerance to the carisoprodol-elicited loss-of-righting reflex. Withdrawal signs were not observed within 24h following spontaneous withdrawal; however, bemegride and flumazenil each precipitated withdrawal within 15-30 min of administration. CONCLUSIONS Carisoprodol treatment resulted in tolerance and antagonist-precipitated withdrawal, suggesting it may have an addiction potential similar to that of other long-acting benzodiazepine or barbiturate compounds.
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Tse SA, Atayee RS, Best BM, Pesce AJ. Evaluating the Relationship Between Carisoprodol Concentrations and Meprobamate Formation and Inter-Subject and Intra-Subject Variability in Urinary Excretion Data of Pain Patients. J Anal Toxicol 2012; 36:221-31. [PMID: 22511696 DOI: 10.1093/jat/bks018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Stephanie A Tse
- University of California, San Diego (UCSD), Skaggs School of Pharmacy & Pharmaceutical Sciences, La Jolla, CA, USA
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Waldman HJ, Waldman SD, Kidder KA. Centrally Acting Skeletal Muscle Relaxants and Associated Drugs. Pain Manag 2011. [DOI: 10.1016/b978-1-4377-0721-2.00125-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Høiseth G, Karinen R, Sørlid HK, Bramness JG. The Effect of Scheduling and Withdrawal of Carisoprodol on Prevalence of Intoxications with the Drug. Basic Clin Pharmacol Toxicol 2009; 105:345-9. [DOI: 10.1111/j.1742-7843.2009.00459.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
INTRODUCTION Texas poison centers identified carisoprodol as a skeletal muscle relaxant that is subject to abuse, and this investigation explores the abuse reported by Texas poison centers. METHODS This study used data from six Texas poison centers to describe the epidemiology of carisoprodol abuse and drug identification (ID) calls from 1998 to 2003. RESULTS Drug ID and abuse calls were 217% higher in 2003 than in 1998. Although eastern and central Texas contains 43% of the state's population, this region reported 77% of all drug ID calls and 64% of abuse calls. For male patients, 51% of the calls were abuse calls and 37% were other human carisoprodol exposure calls. Patients from 13 to 19 years of age accounted for 17% of abuse calls and 9% of other human exposure calls. Among those human exposure calls with a known medical outcome, a higher percentage of abuse calls involved minor effects while a greater proportion of other human exposure calls involved outcomes that ranged from moderate effects to death. CONCLUSIONS Carisoprodol abuse is increasing in Texas and is substantially more common in the eastern part of the state. Carisoprodol abuse is much more likely, than other types of adverse carisoprodol exposures, to involve males and adolescents; and it less likely to involve adverse medical outcomes.
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Abstract
Carisoprodol is a commonly used centrally acting muscle relaxant. A number of case reports have suggested that the drug may have abuse potential, presumably because it is metabolized to the anxiolytic drug, meprobamate, which is a controlled substance at the federal level. Two recent case reports described symptoms of withdrawal after the cessation of carisoprodol. We present two additional cases that support the concept of a withdrawal syndrome with this drug. Symptoms of carisoprodol withdrawal include anxiety, tremulousness, insomnia, jitteriness, muscle twitching, and hallucinations. These symptoms are most likely caused by withdrawal from the meprobamate that accumulates after large amounts of carisoprodol are ingested. Although carisoprodol is not a controlled substance at the federal level, clinicians should be aware of its significant potential for abuse.
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Affiliation(s)
- Roy R Reeves
- Mental Health Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, Mississippi 39216, USA.
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Affiliation(s)
- Gautam Rohatgi
- Department of Psychiatry, University of Medicine and Dentistry of New Jersey-Stratford, NJ, USA
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Bramness JG, Skurtveit S, Gulliksen M, Breilid H, Steen VM, Mørland J. The CYP2C19 genotype and the use of oral contraceptives influence the pharmacokinetics of carisoprodol in healthy human subjects. Eur J Clin Pharmacol 2005; 61:499-506. [PMID: 16021435 DOI: 10.1007/s00228-005-0970-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 06/15/2005] [Indexed: 10/25/2022]
Abstract
AIMS The aim of the present study was to investigate if subjects with one normal and one non-functional CYP2C19 allele (intermediate metabolizers; IMs) metabolized carisoprodol differently than individuals with two normal CYP2C19 alleles (extensive metabolizers; EMs) We also wanted to investigate whether the use of oral contraceptives influences the metabolism of carisoprodol in EMs and IMs. Impairing effects on psychomotor coordination and feelings of sedation were studied by comparing IMs with EMs following their ingestion of a single dose of 700 mg carisoprodol. METHODS Thirty-seven healthy Caucasian volunteers participated in the study, of whom 25 were not using any drugs known to interact with CYP2C19, including two poor metabolizers (PMs) (CYP2C19 *2/*2 or CYP2C19 *2 /*4), 11 IMs (CYP2C19 *1/*2 or CYP2C19 *1/*4) and 12 EMs (CYP2C19 *1/*1); the remaining 12 participants were six EMs and six IMs using oral contraceptives. A single oral dose of 700 mg of carisoprodol was given, and blood drug concentrations were followed for 11 h and 45 min. During this time period, different pharmacodynamic measurements were made. RESULTS IMs had a longer elimination half life (T(1/2)) (127 min; 95% confidence interval (CI) 95, 159) than EMs (96 min; 95% CI 84, 107) and a larger area under the concentration-time curve from 0 to infinity (AUC(0-infinity)) for carisoprodol (16.3 microg h ml(-1) ; 95% CI 11.9, 20.7) than EMs (11.3 microg h ml(-1) ; 95% CI 7.8, 14.8). The use of oral contraceptives was accompanied by larger AUC(0-infinity) for carisoprodol in both EMs (18.5 microg h ml(-1); 95% CI 10.7, 26.3) and IMs (26.0 microg h ml(-1) ; 95% CI 18.8, 33.2). EMs using oral contraceptives also had a longer T(1/2) (117 min; 95% CI 92, 143) and higher maximum carisoprodol concentration than EMs not using oral contraceptives. No significant differences in pharmacodynamic parameters were found between subjects in the different genotype groups or between users and non-users of oral contraceptives. CONCLUSIONS Subsequent to a single-dose administration of carisoprodol, the carisoprodol AUC was approximately 45% larger in CYP2C19 IMs than in EMs. The use of oral contraceptives increased the AUC by approximately 60% in both EMs and IMs. Despite these pharmacokinetic effects, no significant differences with respect to the CYP2C19 IM and EM genotypes were observed in the acute impairing effects of a single dose of carisoprodol.
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Affiliation(s)
- Jørgen G Bramness
- Norwegian Institute of Public Health, Division of Forensic Toxicology and Drug Abuse, P.O. Box 4404, Nydalen, 0403, Oslo, Norway.
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Abstract
The symptoms and signs of carisoprodol intoxications do not resemble those caused by its metabolite meprobamate. Meprobamate most probably produces its effects through the GABAergic neurotransmitter system. The signs and symptoms of carisoprodol intoxications, however, are not easily explained by interaction with this neurotransmitter system. In the present study, four cases of carisoprodol intoxications are presented with emphasis on the presence of serotonergic signs and symptoms. All four cases fulfilled three different sets of criteria for the diagnosis of serotonin syndrome. These findings could indicate that an increased serotonin level in the central nervous system could explain some of the symptoms and signs of carisoprodol intoxications. This may have implications for the clinical evaluation and treatment of such intoxications. Since few laboratories routinely screen for carisoprodol it is important to keep this drug in mind when encountering intoxications displaying serotonergic symptoms.
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Affiliation(s)
- Jørgen G Bramness
- Division of Forensic Toxicology and Drug Abuse, Norwegian Institute of Public Health, Oslo, Norway.
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Abstract
Muscle strains and other musculoskeletal disorders (MSDs) are a leading cause of work absenteeism. Muscle pain, spasm, swelling, and inflammation are symptomatic of strains. The precise relationship between musculoskeletal pain and spasm is not well understood. The dictum that pain induces spasm, which causes more pain, is not substantiated by critical analysis. The painful muscle may not show EMG activity, and when there is, the timing and intensity often do not correlate with the pain. Clinical and physiologic studies show that pain tends to inhibit rather than facilitate reflex contractile activity. The decision to treat and choice of therapy are largely dictated by the duration, severity of symptoms, and degree of dysfunction. Trigger point injections are sometimes used with excellent results in the treatment of muscle spasm in myofacial pain and low-back pain. NSAIDs are used with much greater frequency than oral skeletal muscle relaxants (SMRs) or opioids in the treatment of acute MSDs. Unfortunately, remarkably little sound science guides the choice of drug for the treatment of acute, uncomplicated MSDs, and the evaluation of efficacy of one agent over another is complicated by numerous factors. Only a limited number of high-quality, randomized, controlled trials (RCTs) provide evidence of the effectiveness of NSAIDs or SMRs in the treatment of acute, uncomplicated MSDs. The quality of design, execution, and reporting of trials for the treatment of MSDs needs to be improved. The combination of an SMR and an NSAID or COX-2 inhibitor or the combination of SMR and tramadol/acetaminophen is superior to single agents alone.
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Affiliation(s)
- Frank A Beebe
- New World Health, Division of Nelson Communications Co. Inc., 202 Carnegie Center, Suite 101, Princeton, NJ 08540, USA.
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Abstract
A 43-year-old man with chronic back and shoulder pain was treated with hydrocodone. He began taking excessive amounts of the drug, so his physicians stopped prescribing it. The patient then obtained the muscle relaxant carisoprodol on his own from several sources. He was consuming up to 30 or more tablets/day (> or =10,500 mg/day) for several weeks, then abruptly stopped taking the drug. Within 48 hours he developed anxiety, tremors, muscle twitching, insomnia, auditory and visual hallucinations, and bizarre behavior. The symptoms intensified and peaked on the fourth day after carisoprodol cessation. The patient required brief treatment with olanzapine and tapering dosages of lorazepam while the symptoms gradually resolved. To our knowledge, this is the first documented case of a withdrawal syndrome with carisoprodol. The symptoms most likely resulted because of accumulation of meprobamate, the active metabolite of carisoprodol in humans. Clinicians prescribing carisoprodol should be aware of the possibility for abuse or addiction. Further, we recommend that carisoprodol be designated a controlled substance at the federal level.
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Affiliation(s)
- Roy R Reeves
- G.V. (Sonny) Montgomery VA Medical Center, School of Medicine, University of Mississippi, Jackson, Mississippi, USA.
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Abstract
Carisoprodol is a noncontrolled skeletal muscle relaxant whose active metabolite is meprobamate, a Schedule IV controlled substance. Although several case reports have shown that carisoprodol has abuse potential, it continues to be widely prescribed. The usage patterns of 40 patients who had taken carisoprodol for three or more months (20 of whom had no history of substance abuse and 20 of whom carried a diagnosis of substance abuse or dependence) were reviewed and compared and a survey was conducted to assess physician awareness of the abuse potential of the drug. Findings showed that some patients using carisoprodol for over three months may abuse the medication, especially those individuals with a history of substance abuse. A significant percentage of the physician population is unaware of the potential of carisoprodol for abuse and of its metabolism to meprobamate, a controlled substance. Physicians should exercise caution when prescribing carisoprodol, especially if the patient has a history of substance abuse.
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Affiliation(s)
- R R Reeves
- G.V. (Sonny) Montgomery VA Medical Center, University of Mississippi School of Medicine, Jackson 39216, USA
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Abstract
STATEMENT OF PROBLEM Successful preoperative and postoperative care often depends on systemically administered drugs. The competent and successful practitioner must therefore have a strong background in basic pharmacology, be knowledgeable of pharmacotherapeutics, and keep abreast of the latest advances in medicinal agents. PURPOSE The purpose of this article is to review pharmacologic properties of prototype and new drugs that are primarily used to allay anxiety and pain or reduce inflammation and infection. This information should enable clinicians to improve clinical outcomes and make a more knowledgeable assessment and comparison of standard drugs with recently released drugs.
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Affiliation(s)
- L P Felpel
- University of Texas Health Science Center at San Antonio, USA
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Abstract
A review of available studies supports a role for muscle relaxants in the treatment of painful musculoskeletal disorders. The utility of these drugs is limited by sedation and other side effects, as well as by the potential for abuse and dependency. Other drugs can also be used in the treatment of muscle spasm, specifically diazepam, baclofen, dantrolene sodium, and quinine sulfate. The pharmacology of the muscle relaxants and these other agents is discussed and practical suggestions for use are offered.
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Affiliation(s)
- H J Waldman
- Pain Consortium of Greater Kansas City, Leawood
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