Subjective, psychomotor, and physiological effects of pregabalin alone and in combination with oxycodone in healthy volunteers

Effects of Gabapentinoids on Heroin-Induced Ventilatory Depression and Reversal by Naloxone

Despite an increasing prevalence of gabapentinoids (gabapentin and pregabalin) in opioid overdose deaths, little research has evaluated potentially harmful interactions between gabapentinoids and opioids. This study sought to determine the effects of gabapentinoids on the ventilatory depressive effects of heroin and their reversal by naloxone. Rats were given gabapentin, pregabalin, or saline prior to receiving increasing doses of heroin while ventilation was monitored using whole-body plethysmography. In some sessions naloxone was administered following the largest dose of heroin. The primary outcomes of this study were minute volume and Pause. Heroin dose-dependently reduced minute volume and increased Pause. Administration of naloxone dose-dependently reversed the effects of heroin on ventilation. Gabapentinoids did not alter the ventilatory depressive effects of heroin alone but reduced the potency of naloxone to reverse heroin-induced ventilatory depression. These preliminary findings emphasize the need for further research evaluating interactions between gabapentinoids and opioids related to substance misuse and overdose.

Gabapentin increases the abuse liability of alcohol alone and in combination with oxycodone in participants with co-occurring opioid and alcohol use disorder

BACKGROUND

People who have co-occurring Alcohol Use Disorder (AUD) and Opioid Use Disorder (OUD) carry a higher risk of adverse outcomes, including drug overdose. Early clinical and preclinical studies suggested that gabapentin may be effective in treating both disorders. The present study was designed to assess the effects of gabapentin on the subjective and physiological effects of oxycodone (OXY) and alcohol (ALC), alone and in combination.

METHODS

During an 8-week, inpatient, within-subject, randomized, double-blind, placebo-controlled crossover study, non-treatment seeking participants (N = 13; 12 M/1F; 44.1 ± 3 years of age) with OUD and AUD were maintained on oral morphine (120 mg daily). Under gabapentin (1800 mg/day) and placebo (0 mg/day) maintenance, participants completed nine separate test sessions (three sessions per week) during which they received an oral solution containing 0, 15, or 30 mg/70 kg OXY in combination with 0, 0.5, or 0.75 g/kg ALC. During test sessions, subjective effects and physiological responses were assessed repeatedly on 100-mm visual analog scales (VAS). The primary outcome variable was the VAS rating of drug liking after receiving the drug challenge.

RESULTS

Alcohol alone (but not oxycodone alone) produced dose-related increases in several positive subjective responses, including drug liking. Gabapentin significantly increased drug liking when given in combination with ALC and OXY + ALC (p < 0.05). Gabapentin did not clinically compromise respiration or other vital functions.

CONCLUSIONS

Gabapentin may increase the abuse liability of ALC and OXY + ALC in those with co-occurring OUD and AUD.

Advances in the clinical application of oxycodone in the perioperative period

To review the research progress of pure opioid receptor agonist oxycodone. The research progress of oxycodone in terms of pharmacokinetics, pharmacodynamics, adverse reactions, clinical application, combined medication and new progress in clinical application was summarized by referring to the literature. Oxycodone is a semi-synthetic thebaine derivative of opioid alkaloids, and is a pure opioid μ and κ receptor agonist. The main action sites are the central nervous system and visceral smooth muscle. Due to its advantages of low adverse reactions, good analgesic effects, and a wide range of safe doses, the drug has been widely used in the control of acute and chronic postoperative pain, as well as malignant and non-malignant pain. Since the end of the 20^th century, researchers have begun to formulate antipyretic analgesics, opioid receptor agonists, opioid receptor antagonists, dopamine receptor antagonists and other drugs with oxycodone in different proportions to enhance the analgesic effect. At the same time, it can reduce the dosage of oxycodone and reduce its adverse reactions, so as to achieve the purpose of limiting opioid abuse. With the continuous research on the efficacy and safety of oxycodone in the perioperative period at home and abroad, oxycodone has become the only dual-opioid potent analgesic that can be used in clinical work.

How prevalent and severe is addiction on GABAmimetic drugs in an elderly German general hospital population? Focus on gabapentinoids, benzodiazepines, and z-hypnotic drugs

OBJECTIVE

Gabapentinoids (GPT) are reported to be increasingly misused by opioid- and polydrug-users, but the addictive potential of GPT outside of these populations remains understudied. Investigations comparing GPT abuse and dependence liability to that of other commonly prescribed Central Nervous System-acting medications are therefore warranted. We provide a comparison of GPT-abuse/dependence to that of other GABAmimetics within an elderly population.

DESIGN

DSM-IV-TR-based data (previously prospectively collected by SKID-I-interview) from a random sample of elderly patients admitted to a metropolitan German general hospital were reviewed. The prevalence and severity of GPT, benzodiazepine (BDZ), and z-hypnotic drug (ZD)-abuse and -dependence were compared, stratified also by mono-substance (no concurrent current or previous substance use) and de novo-substance (first)-abuse and -dependence states.

RESULTS

Among 400 patients (75 ± 6.4 years old; 63% females), neither current nor past abuse of BDZ, ZD or GPT, nor other illicit substances was observed. Dependence upon BDZ, ZD or GPT was observed among 55 (13.75%) individuals. The related lifetime/12-month prevalence-rates were: dependence condition (BDZ: 7%/2.45%; ZD: 4.25%/4.25%; GPT: 2.75/2.5%); mono-dependence condition (BDZ: 2.25%/0.75%; ZD: 1%/1%, GPT: 0%/0%); de novo-dependence condition (BDZ: 2.75%/1.75%; ZD: 1%/1%, GPT: 0.5%/0.5%). Opioid analgesic-dependence (N = 43/400) was significantly more frequently linked with BDZ than with GPT (p < 0.01) [Correction added on 29 December 2021, after first online publication: In the sentence 'Opioid analgesic-dependence…', the term 'and ZD' has been deleted]. For all three GABAmimetic classes, most mono- and de novo-dependence states were mild-to-moderate and lasted 2-6 years (median).

CONCLUSION

GABAmimetic-dependence was usually mixed with other substance-dependences. Every third to fourth instance of BDZ- or ZD-dependence was a mono-dependence condition, while a pure GPT-dependence was absent in this elderly (and illicit substance-naïve) population.

Proposing a "Brain Health Checkup (BHC)" as a Global Potential "Standard of Care" to Overcome Reward Dysregulation in Primary Care Medicine: Coupling Genetic Risk Testing and Induction of "Dopamine Homeostasis"

In 2021, over 100,000 people died prematurely from opioid overdoses. Neuropsychiatric and cognitive impairments are underreported comorbidities of reward dysregulation due to genetic antecedents and epigenetic insults. Recent genome-wide association studies involving millions of subjects revealed frequent comorbidity with substance use disorder (SUD) in a sizeable meta-analysis of depression. It found significant associations with the expression of NEGR1 in the hypothalamus and DRD2 in the nucleus accumbens, among others. However, despite the rise in SUD and neuropsychiatric illness, there are currently no standard objective brain assessments being performed on a routine basis. The rationale for encouraging a standard objective Brain Health Check (BHC) is to have extensive data available to treat clinical syndromes in psychiatric patients. The BHC would consist of a group of reliable, accurate, cost-effective, objective assessments involving the following domains: Memory, Attention, Neuropsychiatry, and Neurological Imaging. Utilizing primarily PUBMED, over 36 years of virtually all the computerized and written-based assessments of Memory, Attention, Psychiatric, and Neurological imaging were reviewed, and the following assessments are recommended for use in the BHC: Central Nervous System Vital Signs (Memory), Test of Variables of Attention (Attention), Millon Clinical Multiaxial Inventory III (Neuropsychiatric), and Quantitative Electroencephalogram/P300/Evoked Potential (Neurological Imaging). Finally, we suggest continuing research into incorporating a new standard BHC coupled with qEEG/P300/Evoked Potentials and genetically guided precision induction of "dopamine homeostasis" to diagnose and treat reward dysregulation to prevent the consequences of dopamine dysregulation from being epigenetically passed on to generations of our children.

Gabapentinoid Pharmacology in the Context of Emerging Misuse Liability

This article will review the epidemiology and pharmacology of gabapentinoids (gabapentin and pregabalin) relevant to their emerging misuse potential and provide guidance for clinical and regulatory management. Gabapentinoids are γ-aminobutyric acid analogues that produce their therapeutic effects by inhibiting voltage-gated calcium channels and decreasing neurotransmitter release. Recently gabapentinoid prescribing and use have increased tremendously. Although traditionally thought to possess a favorable safety profile, gabapentinoid misuse has also risen significantly. Gabapentinoid misuse generally occurs in combination with other substances, most notably opioids, and may be for purposes of eliciting euphoric effects, enhancing the effects of other substances, or self-treating conditions such as withdrawal, pain, anxiety, or insomnia. Given its faster onset, increased bioavailability and potency, and nonsaturable absorption, pregabalin's pharmacokinetics theoretically enhance its misuse liability versus gabapentin. However, gabapentin can produce similar euphoric effects, and epidemiologic studies have identified higher rates of gabapentin misuse in the United States, likely because of greater availability and less regulated prescribing. Although adverse events of gabapentinoid-only ingestion are relatively benign, a growing body of evidence indicates that gabapentinoids significantly increase opioid-related morbidity and mortality when used concomitantly. In addition, significant withdrawal effects may occur on abrupt discontinuation. As a result of these trends, several US states have begun to further regulate gabapentinoid prescribing, reclassifying it as a controlled substance or mandating reporting to local prescription drug-monitoring programs. Although increased regulation of gabapentin prescribing may be warranted, harm reduction efforts and increased patient and provider education are necessary to mitigate this concerning gabapentinoid misuse trend.

Pregabalin for neuropathic pain in primary care settings: recommendations for dosing and titration

Pregabalin is one of the first-line treatments approved for the management of neuropathic pain (NeP). While many patients benefit from treatment with pregabalin, they are often treated with suboptimal doses, possibly due to unfamiliarity around prescribing the drug and/or side effects that can occur with up-titration. This narrative review discusses key aspects of initiating, titrating, and managing patients prescribed pregabalin therapy, and addresses concerns around driving and the potential for abuse, as well as when to seek specialist opinion. To ensure that patients derive maximum therapeutic benefit from the drug, we suggest a 'low and slow' dosing approach to limit common side effects and optimize tolerability alongside patients' expectations. When requiring titration to higher doses, we recommend initiating 'asymmetric dosing,' with the larger dose in the evening. Fully engaging patients in order for them to understand the expected timeline for efficacy and side effects (including their resolution), can also help determine the optimal titration tempo for each individual patient. The 'low and slow' approach also recognizes that patients with NeP are heterogeneous in terms of their optimal therapeutic dose of pregabalin. Hence, it is recommended that general practitioners closely monitor patients and up-titrate according to pain relief and side effects to limit suboptimal dosing or premature discontinuation.

Current Evidence on Abuse and Misuse of Gabapentinoids

This review summarizes current evidence on the abuse and misuse of the gabapentinoids pregabalin and gabapentin. Pharmacovigilance studies, register-based studies, surveys, clinical toxicology studies, and forensic toxicology studies were identified and scrutinized with the goal to define the problem, identify risk factors, and discuss possible methods to reduce the potential for abuse and misuse. Studies found that gabapentinoids are abused and misused and that individuals with a history of psychiatric disorders or substance use disorder seem to be at high risk. Moreover, some evidence supports the notion that patients with opioid use disorders may be at an increased risk of abusing gabapentinoids. Available evidence also suggests that abuse and misuse are more frequent in users of pregabalin compared with users of gabapentin. Health professionals and prescribers should be aware of the risk for misuse of pregabalin and gabapentin, which eventually could lead to abuse, substance dependence, and intoxications. Prescribing to patients belonging to risk populations such as those with psychiatric disorders or substance use disorder should be avoided if possible and, if prescribed, signs of misuse and abuse should be monitored.

Increased postoperative dexamethasone and gabapentin reduces opioid consumption after total knee arthroplasty

PURPOSE

Dexamethasone and gabapentin are used in multimodal pain management protocols to reduce postoperative pain after total knee arthroplasty. For both analgesic adjuvants, the optimal dose regimen to reduce opioid usage is still unclear.

METHODS

The opioid consumption of patients undergoing primary TKA before and after a change of the analgesic adjuvant medication in our protocol (old protocol: 4 mg of dexamethasone daily for 2 days, 600 mg gabapentin daily for 1 week; new protocol: 10 mg dexamethasone daily for 2 days, 300 mg gabapentin every 8 h for 1 week) were retrospectively compared. All surgeries were performed under spinal anesthesia. Peri- and postoperative pain medication remained unchanged.

RESULTS

A total of 186 patients who received TKA between 11/29/2016 and 06/09/2017 were screened. Six patients who received general anesthesia, 4 patients who underwent simultaneous bilateral TKA, and 16 patients with ongoing opioid consumption at the time of surgery were excluded, leaving 80 patients in each group. Opioid consumption within 24 h [morphine equivalents in mg: mean 50.5, standard deviation (SD) 30.0 (old) vs. 39.8, SD 24.2 (new); P = 0.0470], cumulative consumption over 48 h (97.3, SD 64.4 vs. 70.4, SD 51.2; P = 0.0040) and cumulative consumption over 72 h (108.1, SD 79.5 vs. 82.5, SD 72.6; P = 0.0080), were all significantly lower in the new protocol.

CONCLUSION

Increased postoperative administration of dexamethasone and gabapentin after TKA is associated with lower opioid consumption. Within the first 48 h, up to about 25% of opioids can be spared, comparing high-dose to low-dose protocols.

LEVEL OF EVIDENCE

Therapeutic Level III.

Cognitive Effects of Perioperative Pregabalin

EDITOR’S PERSPECTIVE

What We Already Know about This Topic

Perioperative administration of pregabalin has been associated with decreased postoperative pain and opioid requirements

What This Article Tells Us That Is New

This secondary analysis of data demonstrating that perioperative administration of pregabalin was associated with a reduction in opioid requirements and incisional hyperalgesia suggests that these benefits may be compromised by an increased risk of developing impaired postoperative cognitive performance

Background

Pregabalin has shown opioid sparing and analgesic effects in the early postoperative period; however, perioperative effects on cognition have not been studied. A randomized, parallel group, placebo-controlled investigation in 80 donor nephrectomy patients was previously performed that evaluated the analgesic, opioid-sparing, and antihyperalgesic effects of pregabalin. This article describes a secondary exploratory analysis that tested the hypothesis that pregabalin would impair cognitive function compared to placebo.

Methods

Eighty patients scheduled for donor nephrectomy participated in this randomized, placebo-controlled study. Pregabalin (150 mg twice daily, n = 40) or placebo (n = 40) was administered on the day of surgery and the first postoperative day, in addition to a pain regimen consisting of opioids, steroids, local anesthetics, and acetaminophen. Specific cognitive tests measuring inhibition, sustained attention, psychomotor speed, visual memory, and strategy were performed at baseline, 24 h, and 3 to 5 days after surgery, using tests from the Cambridge Neuropsychological Test Automated Battery.

Results

In the spatial working memory within errors test, the number of errors increased with pregabalin compared to placebo 24 h after surgery; median (25th, 75th percentile) values were 1 (0, 6) versus 0 (0, 1; rate ratio [95% CI], 3.20 [1.55 to 6.62]; P = 0.002). Furthermore, pregabalin significantly increased the number of errors in the stop-signal task stop-go test compared with placebo; median (25th, 75th percentile) values were 3 (1, 6) versus 1 (0, 2; rate ratio, 2.14 [1.13 to 4.07]; P = 0.020). There were no significant differences between groups in the paired associated learning, reaction time, rapid visual processing, or spatial working memory strategy tests.

Conclusions

Perioperative pregabalin significantly negatively affected subdomains of executive functioning, including inhibition, and working memory compared to placebo, whereas psychomotor speed was not changed.

Pregabalin Misuse and Abuse: A Scoping Review of Extant Literature

Prescribing of pregabalin is increasing worldwide with public health concerns centering on misuse and abuse of prescribed and diverted pregabalin. To describe and map what is known about misuse and abuse of pregabalin, a scoping review of available published literature was undertaken. A scoping review methodology was used to identify and map available literature on misuse and abuse of prescribed and diverted pregabalin. Four themes emerged on the misuse and abuse of pregabalin: (a) abuse potential, (b) prevalence of abuse, (c) risk and predisposition, and (d) consequences of abuse. Fifty-four records were reviewed and charted. Of note was the dearth of research on the topic prior to 2005, with increased interest in pregabalin abuse potential from 2010 onward. Available literature supports concern around abuse potential of pregabalin, especially among patients with a history of substance abuse. Prescribers should adopt more rational prescribing.

How addictive are gabapentin and pregabalin? A systematic review

In the last ten years, gabapentin and pregabalin have been becoming dispensed broadly and sold on black markets, thereby, exposing millions to potential side-effects. Meanwhile, several pharmacovigilance-databases have warned for potential abuse liabilities and overdose fatalities in association with both gabapentinoids. To evaluate their addiction risk in more detail, we conducted a systematic review on PubMed/Scopus and included 106 studies. We did not find convincing evidence of a vigorous addictive power of gabapentinoids which is primarily suggested from their limited rewarding properties, marginal notes on relapses, and the very few cases with gabapentinoid-related behavioral dependence symptoms (ICD-10) in patients without a prior abuse history (N=4). In support, there was no publication about people who sought treatment for the use of gabapentinoids. Pregabalin appeared to be somewhat more addictive than gabapentin regarding the magnitude of behavioral dependence symptoms, transitions from prescription to self-administration, and the durability of the self-administrations. The principal population at risk for addiction of gabapentinoids consists of patients with other current or past substance use disorders (SUD), mostly opioid and multi-drug users, who preferred pregabalin. Pure overdoses of gabapentinoids appeared to be relative safe but can become lethal (pregabalin > gabapentin) in mixture with other psychoactive drugs, especially opioids again and sedatives. Based upon these results, we compared the addiction risks of gabapentin and pregabalin with those of traditional psychoactive substances and recommend that in patients with a history of SUD, gabapentinoids should be avoided or if indispensable, administered with caution by using a strict therapeutic and prescription monitoring.

Risk of respiratory depression with opioids and concomitant gabapentinoids

INTRODUCTION

The combination of opioids and central nervous system depressants such as benzodiazepines and barbiturates has an additive effect on the frequency of oversedation and respiratory depression requiring naloxone use in hospitalized patients. Gabapentinoids (gabapentin and pregabalin) are frequently prescribed with opioids for their opioid-sparing and adjuvant analgesic effects. There is limited literature on the risk of respiratory depression due to the combination of opioids and gabapentinoids requiring naloxone administration.

METHODS

This retrospective study evaluated patients who were prescribed opioids and at least one dose of naloxone between March 1, 2014 and September 30, 2016. The primary objective of this study was to compare the frequency of respiratory depression among patients who received naloxone and opioids (non-gabapentinoid group) with those who received naloxone, opioids, and gabapentinoids (gabapentinoid group). Secondary objectives included comparing the association of oversedation, using the Pasero Opioid-induced Sedation Scale, and various risk factors with those in the gabapentinoid group.

RESULTS

A total of 153 patient episodes of naloxone administration (102 in the non-gabapentinoid and 51 in the gabapentinoid groups) in 125 unique patients were included in the study. For the primary objective, there were 33 episodes of respiratory depression associated with the non-gabapentinoid group (33/102=32.4%) versus 17 episodes of respiratory depression with the gabapentinoid group (17/51=33.3%) (p=0.128). Secondary objectives showed a significant association between respiratory depression and surgery in the previous 24 hours (p=0.036) as well as respiratory depression and age >65 years (p=0.031) for patients in the non-gabapentinoid group compared to the gabapentinoid group.

CONCLUSION

There was no significant association of respiratory depression in the gabapentinoid group versus the non-gabapentinoid group. There was an increased risk of respiratory depression in the gabapentinoid group, specifically in patients who had surgery within the previous 24 hours.

Benzodiazepine, z-drug and pregabalin prescriptions and mortality among patients in opioid maintenance treatment-A nation-wide register-based open cohort study

BACKGROUND

Use of sedatives may increase risk of death in opioid users. The aim of the study was to assess whether prescription of sedatives may be associated with mortality in patients in opioid maintenance treatment.

METHODS

This retrospective register-based open cohort study included nation-wide register data including all individuals who were dispensed methadone or buprenorphine as opioid maintenance treatment for opioid dependence between July, 2005 and December, 2012 (N=4501). Outcome variables were overdose mortality and non-overdose mortality, respectively. Extended Cox regression analyses examined associations between type of sedative prescriptions and death, controlling for sex, age, previous overdoses and suicide attempts, psychiatric in-patient treatment and opioid maintenance treatment status. Opioid maintenance was assumed to last for 90days (or 30days in a sensitivity analysis) after the last methadone or buprenorphine prescription.

RESULTS

Benzodiazepine prescriptions were associated with non-overdose death (HR: 2.02, 95% CI: 1.29-3.18) but not significantly associated with overdose death (1.49, 0.97-2.29). Z-drug (1.60, 1.07-2.39) and pregabalin prescriptions (2.82, 1.79-4.43) were associated with overdose death. In the sensitivity analysis, all categories of sedatives, including benzodiazepines, were significantly associated with overdose death.

CONCLUSIONS

Caution is advised when prescribing sedative drugs, including benzodiazepines, z-drugs and pregabalin, to patients in opioid maintenance treatment.

Nonmedical Use of Antihistaminergic Anxiolytics and Other Prescription Drugs among Persons with Opioid Dependence

Background. Nonmedical prescription drug use (NMPDU) is an increasing problem, insufficiently studied among people in opioid maintenance treatment (OMT). This study investigates the prevalence of and factors associated with NMPDU for drug classes insufficiently described in opioid-dependent populations, including antihistaminergic anxiolytics and central stimulants. Methods. Study participants were recruited at two OMT clinics in Malmo, Sweden, between October 2014 and December 2015 (N = 73) and interviewed about their use, motivations for use, and acquisition and administration of prescription drugs. Results. The majority of the sample reported lifetime NMPDU: 60% for benzodiazepine-like hypnotics (z-drugs), 21% for pregabalin, 19% for stimulants, and 12%-15% for antihistaminergic anxiolytics. Lower age was associated with nonmedical benzodiazepine use (Adjusted Odds Ratio = 0.89; 95% Confidence Interval = 0.82-0.97). Illicit acquisition was reported by 61% of people using z-drugs, 46% of people using pregabalin, and 38% of people using prescription stimulants, but only by 6-10% of people using antihistaminergic anxiolytics. Conclusions. The substantial nonmedical use of pregabalin, z-drugs, and prescription stimulants found in this study suggests that clinicians should prescribe these drugs with great caution. Nonmedical use of antihistaminergic anxiolytics does not seem to be a clinical issue among people in OMT in a Swedish setting, but we propose future studies to monitor their use.

Gabapentin can significantly improve dystonia severity and quality of life in children

INTRODUCTION

Gabapentin has been used in the management of neuropathic pain, epilepsy and occasionally movement disorders.

METHODS

A four-year retrospective, observational study analysed the use of gabapentin for severe dystonia in children at the Evelina London Children's Hospital. Motor severity was classified according to the Gross Motor Function Classification System (GMFCS), Dystonia Severity Assessment Plan (DSAP) and levels of impairment in activities of daily living were graded according to the WHO International Classification of Functioning, Disability and Health, Children & Youth version (ICF-CY) before and after gabapentin.

RESULTS

The majority of the 69 children reported were level 5 GMFCS (non-ambulant). The DSAP grade fell significantly from grade 3 before to grade 1 after gabapentin. Significant improvements in median ICF-CY grades were seen following gabapentin in sleep quality, sleep amount, mood & agreeableness, pain, general muscle tone, involuntary muscle contractions and seating tolerance (p < 0.01 in all areas). A significantly higher mean dose of 18.1 mg/kg/dose (SD: 13.3) for dystonia, compared to 7.61 mg/kg/dose (SD: 4.14) for pain relief without dystonia (z = -2.54, p = 0.011) was noted.

DISCUSSION & CONCLUSION

Gabapentin may significantly ameliorate dystonia severity and improve activities of daily living and quality of life in children with severe dystonia.

Prescription Drug Misuse and Sexual Behavior Among Young Adults

Though research indicates a complex link between substance use and sexual risk behavior, there is limited research on the association between sexual risk behavior and prescription drug misuse. In light of alarming increases in prescription drug misuse and the role of demographic characteristics in sexual risk behavior and outcomes, the current study examined demographic differences (gender, sexual identity, age, relationship status, parental class background, and race/ethnicity) in sexual risk behavior, sexual behavior under the influence of prescription drugs, and sexual risk behavior under the influence of prescription drugs in a sample of 402 young adults (ages 18 to 29) who misused prescription drugs. Nearly half of the sexually active young adult prescription drug misusers in this sample reported recent sex under the influence of prescription drugs; more than three-quarters reported recent sex without a condom; and more than one-third reported recent sex without a condom after using prescription drugs. Zero-inflated Poisson regression models indicated that White race, younger age, higher parental class, and being a heterosexual man were all associated with sexual risk behavior, sex under the influence of prescription drugs, and sexual risk under the influence of prescription drugs. Findings have implications for the targeting of prevention and intervention efforts.

Pregabalin abuse for enhancing sexual performance: case discussion and literature review

Pregabalin is a γ-aminobutyric acid analogue that is primarily prescribed in psychiatry for management of generalized anxiety disorder. The belief in its low potential for abuse has placed it in a superior position to other anxiolytic agents. However, more recent, concerns have been raised about the addictive potential of pregabalin. This problem has not received much attention nor has the mechanism of its development. There is also a lack of understanding of the difference in the experience of abusing pregabalin in contrast to abusing other illicit drugs. We report the case of a 55-year-old patient with a background history of multiple psychoactive substances misuse who elaborated on his own personal experience of pregabalin abuse. He consumed a month’s supply of this medication over 2 days and realized an enhancement in sexual desire and excitement. This effect should be considered when prescribing pregabalin.

Pregabalin serum levels in apprehended drivers

Pregabalin is a medicinal drug used mainly for the treatment of epilepsy and neuropathic pain. It has been shown to possess an abuse potential and in recent years some reports of illegal use have been published. In order to further evaluate the extent and nature of pregabalin abuse, serum pregabalin levels of drivers apprehended for driving under the influence of drugs (DUID) in Finland in 2012 were assessed. The samples were analysed by an LC-MS/MS system and the results were evaluated in relation to the typical therapeutic range of pregabalin as well as the age and gender of the driver. Pregabalin was detected in 206 samples in the study period. The median (range) serum concentration was 6.2 (0.68-111.6)mg/L. In nearly 50% of the cases the serum concentration was above the typical therapeutic range. In most of the cases the driver had also taken other drugs besides pregabalin, the mean number of concomitantly taken drugs being four. Our data indicate that pregabalin is being used at high doses, probably for recreational purposes. The vast majority of the drivers positive for pregabalin in our study material had used pregabalin as a part of a spectrum of psycho-active drugs and thus qualified as probable drug abusers. In these cases pregabalin probably contributed to their driving impairment but to what extent remained unclear in this study.

Misuse and abuse of pregabalin and gabapentin: cause for concern?

Gabapentinoids (e.g. pregabalin and gabapentin) are widely used in neurology, psychiatry and primary healthcare but are increasingly being reported as possessing a potential for misuse. In fact, increasing levels of both prescriptions and related fatalities, together with an anecdotally growing black market, have been reported from a range of countries. This article reviews the current evidence base of this potential, in an attempt to answer the question of whether there is cause for concern about these drugs. Potent binding of pregabalin/gabapentin at the calcium channel results in a reduction in the release of excitatory molecules. Furthermore, gabapentinoids are thought to possess GABA-mimetic properties whilst possibly presenting with direct/indirect effects on the dopaminergic 'reward' system. Overall, pregabalin is characterized by higher potency, quicker absorption rates and greater bioavailability levels than gabapentin. Although at therapeutic dosages gabapentinoids may present with low addictive liability levels, misusers' perceptions for these molecules to constitute a valid substitute for most common illicit drugs may be a reason of concern. Gabapentinoid experimenters are profiled here as individuals with a history of recreational polydrug misuse, who self-administer with dosages clearly in excess (e.g. up to 3-20 times) of those that are clinically advisable. Physicians considering prescribing gabapentinoids for neurological/psychiatric disorders should carefully evaluate a possible previous history of drug abuse, whilst being able to promptly identify signs of pregabalin/gabapentin misuse and provide possible assistance in tapering off the medication.

Evaluation of the effect of pregabalin on simulated driving ability using a driving simulator in healthy male volunteers

Pregabalin, a novel agent for treating partial epilepsy and peripheral neuropathic and central pain, was studied for its effect on driving performance in healthy volunteers. Sixteen healthy male volunteers who drove regularly were enrolled in a double-blind, parallel-group, placebo-controlled study assessing the effect of pregabalin on driving performance. Subjects received an oral dose of pregabalin 75 mg or placebo, and a second dose 12 hours later. A driving simulator was used to test simple and complicated braking reaction time, and simple and complicated steering-wheel techniques before the first dose, and 1 hour and 3 hours after the second dose of pregabalin or placebo. The effect of training during the driving test on the driving performance of each group was also evaluated. There were no statistically significant differences in driving performance between the pregabalin and the placebo groups. However, the pregabalin group showed no significant improvement in steering-wheel skills with training, whereas the placebo group showed a significant (P<0.05) improvement with training. In this study using a driving simulator, pregabalin did not impair driving performance but mildly reduced the training effects of driving experiments. Although pregabalin caused sleepiness, it had no severe effect on driving ability after a second dose of 75 mg after the initial introduction of pregabalin.

Gabapentinoid abuse in order to potentiate the effect of methadone: a survey among substance misusers

BACKGROUND/AIMS

There is emerging evidence of gabapentin and pregabalin (gabapentinoid) abuse, particularly in the substance misuse population, and some suggestion of gabapentinoids being abused alongside methadone.

METHODS

A questionnaire-based survey was carried out in six substance misuse clinics, looking for evidence of gabapentinoid abuse.

RESULTS

22% (29/129) of respondents admitted to abusing gabapentinoids, and of these, 38% (11/29) abused gabapentinoids in order to potentiate the 'high' they obtained from methadone.

CONCLUSIONS

Gabapentinoid abuse along with methadone has not previously been described. These findings are of relevance to clinicians working within both substance misuse services and chronic pain services.

A translational pharmacology approach to understanding the predictive value of abuse potential assessments

Within the drug development industry the assessment of abuse potential for novel molecules involves the generation and review of data from multiple sources, ranging from in-vitro binding and functional assays through to in-vivo nonclinical models in mammals, as well as collection of information from studies in humans. This breadth of data aligns with current expectations from regulatory agencies in both the USA and Europe. To date, there have been a limited number of reviews on the predictive value of individual models within this sequence, but there has been no systematic review on how each of these models contributes to our overall understanding of abuse potential risk. To address this, we analyzed data from 100 small molecules to compare the predictive validity for drug scheduling status of a number of models that typically contribute to the abuse potential assessment package. These models range from the assessment of in-vitro binding and functional profiles at receptors or transporters typically associated with abuse through in-vivo models including locomotor activity, drug discrimination, and self-administration in rodents. Data from subjective report assessments in humans following acute dosing of compounds were also included. The predictive value of each model was then evaluated relative to the scheduling status of each drug in the USA. In recognition of the fact that drug scheduling can be influenced by factors other than the pharmacology of the drug, we also evaluated the predictive value of each assay for the outcome of the human subjective effects assessment. This approach provides an objective and statistical assessment of the predictive value of many of the models typically applied within the pharmaceutical industry to evaluate abuse potential risk. In addition, the impact of combining information from multiple models was examined. This analysis adds to our understanding of the predictive value of each model, allows us to critically evaluate the benefits and limitations of each model, and provides a method for identifying opportunities for improving our assessment and prediction of abuse liability risk in the future.

Pregabalin for the treatment of generalized anxiety disorder: an update

A PREVIOUS REVIEW SUMMARIZED WHAT WAS THEN KNOWN ABOUT THE POTENTIAL ROLE OF PREGABALIN IN THE TREATMENT OF PATIENTS WITH GENERALIZED ANXIETY DISORDER (GAD): this review provides an update on its pharmacological properties and presumed mechanism of action, the liability for abuse, and efficacy and tolerability in patients with GAD. Pregabalin has a similar molecular structure to the inhibitory neurotransmitter gamma amino butyric acid (GABA) but its mechanism of action does not appear to be mediated through effects on GABA. Instead, its anxiolytic effects may arise through high-affinity binding to the alpha-2-delta sub-unit of the P/Q type voltage-gated calcium channel in "over-excited" presynaptic neurons, thereby reducing the release of excitatory neurotransmitters such as glutamate. The findings of randomized controlled trials and meta-analyses together indicate that pregabalin is efficacious in both acute treatment and relapse prevention in GAD, with some evidence of an early onset of effect, and broad efficacy in reducing the severity of psychological and physical symptoms of anxiety. It also has efficacy as an augmenting agent after non-response to antidepressant treatment in GAD. Continuing vigilance is needed in assessing its potential abuse liability but the tolerability profile of pregabalin may confer some advantages over other pharmacological treatments in the short term for treatment in patients with GAD.

Separate and combined psychopharmacological effects of alprazolam and oxycodone in healthy volunteers

BACKGROUND

There are epidemiological data indicating that medical and/or nonmedical use of prescription opioids oftentimes involves concurrent use of other substances. One of those substances is benzodiazepines. It would be of relevance to characterize the effects of an opioid and a benzodiazepine when taken together to determine if measures related to abuse liability-related effects and psychomotor performance impairment are increased compared to when the drugs are taken alone.

METHODS

Twenty volunteers participated in a crossover, randomized, double-blind study in which they received placebo, 0.5mg alprazolam, 10mg oxycodone, and 0.5mg alprazolam combined with 10 mg oxycodone, all p.o. Subjective, psychomotor, and physiological measures were assessed during each of the four sessions.

RESULTS

Oxycodone by itself increased drug liking and "take again" ratings relative to placebo, but these ratings were not increased when oxycodone was taken with alprazolam, which by itself did not increase either of these ratings. The two drugs in combination produced stronger effects (larger in magnitude or longer lasting) than when either was taken alone on a number of measures, including psychomotor performance impairment.

CONCLUSIONS

In healthy volunteers, abuse liability-related subjective effects of oxycodone were not enhanced by alprazolam. There was enhanced behavioral toxicity when the drugs were taken together, and thus, this is of significant concern from a public safety standpoint.

Efficacy and safety of pregabalin in the treatment of alcohol and benzodiazepine dependence

INTRODUCTION

Both alcohol and benzodiazepine dependence (AD, BD) are severe and chronic conditions with devastating physical and mental health effects. The relative scarcity and controversial evidential status of available pharmacological interventions for the treatment of patients' acute withdrawal syndrome and/or relapse prevention call for the clinical investigation of novel safe and efficacious agents.

AREAS COVERED

We review published studies of pregabalin as monotherapy in the treatment of AD and BD in more than 450 patients. Available evidence includes four RCTs, two in AD with active comparator drugs (naltrexone, tiapride, and lorazepam) and one placebo-controlled, and one placebo-controlled in BD. We also review other available studies on pregabalin's potential to reduce benzodiazepine consumption, its side effects, especially cognitive, as well as extant reports on its liability for abuse.

EXPERT OPINION

Available evidence suggests that monotherapy with pregabalin, within the dosage range of 150 - 600 mg/d, is a promising "novel" option for the safe and efficacious relapse prevention of both AD and BD. However, its efficacy as monotherapy in the acute treatment of AD withdrawal syndrome is still controversial. Clinicians should be cautious in prescribing pregabalin to patients with a history of multiple substance recreational use, and monitor its effects on cognition at dosages above 450 mg/d. Further, well-designed clinical research is still needed for the eventual consolidation of pregabalin's place in the treatment of AD and BD.