Abuse liability assessment of eslicarbazepine acetate in healthy male and female recreational sedative users: A Phase I randomized controlled trial.

RATIONALE: Eslicarbazepine acetate (ESL) is a once-daily oral antiepileptic drug for the treatment of partial-onset seizures. Adverse events such as dizziness and somnolence reported in clinical studies suggest that ESL has detectable central nervous system (CNS) effects in addition to its antiepileptic effects. This Phase I study evaluated the abuse liability of ESL compared with that of alprazolam (ALP) and placebo (PBO) in recreational CNS depressant users. METHODS: In this single-dose, randomized, double-blind, PBO- and active-controlled crossover study, healthy recreational CNS depressant users who could discern between ALP 2mg and PBO received single oral doses of each of the following treatments with a washout interval of ≥7days between each treatment: ESL (800mg, 1600mg, 2000mg, and 2400mg); ALP (1.5mg and 3.0mg); and PBO. Subjective measures, including visual analog scales (VASs) e.g., Drug-Liking (primary endpoint), and Addiction Research Center Inventory (ARCI) Morphine-Benzedrine Group (MBG), Pentobarbital Chlorpromazine Alcohol Group (PCAG), and Lysergic Acid Diethylamide Group scales were evaluated at multiple time points up to 24h postdose. Cognitive effects were evaluated using the Choice Reaction Time (CRT), Divided Attention (DAT) and Hopkins Verbal Learning Task-Revised tests. PRINCIPAL RESULTS: Peak scores for Drug-Liking VAS (maximum effect [Emax]) were significantly higher for both ALP doses than for PBO (p<0.0001), thereby confirming study validity. Drug-Liking VAS Emax was significantly lower for all ESL doses than both ALP doses (p<0.0001). Drug-Liking VAS Emax for ESL 800mg was similar to that for PBO (least squares [LS] mean difference: 3.6; p=0.19). At the three higher ESL doses (1600mg and the supratherapeutic doses of 2000mg and 2400mg), Drug-Liking VAS Emax was significantly higher than for PBO, although the differences were minimal (LS mean difference: 9.3-13.3 out of 100). For most secondary subjective endpoints (i.e., Good Effects VAS and High VAS, ARCI-MBG, Take Drug Again VAS, Overall Drug-Liking VAS, and ARCI-PCAG; p<0.05), the effect of ESL (all doses) was significantly less than that of ALP (both doses). On most secondary measures, the dose-response relationship was relatively flat or showed saturation at higher ESL doses. Although significant differences were observed for ESL compared with those for PBO for some specific CRT and DAT endpoints (i.e., reaction time, manual tracking, hit latency), ALP demonstrated significant and dose-dependent impairment on the majority of cognitive endpoints when compared with PBO and ESL. Mean plasma concentrations of the active metabolite of ESL, eslicarbazepine, increased with increasing ESL dose. Pharmacokinetic parameters estimated for eslicarbazepine were generally comparable with results from previous studies in healthy volunteers. CONCLUSION: This study demonstrated that single doses of ESL may have less abuse liability than ALP in recreational sedative users. Although ESL had detectable subjective effects and showed some drug-'liking' at higher doses, the magnitude of these effects was small.

Assessment of Pharmacokinetic and Pharmacodynamic Interactions Between Albumin-Fused Mutated Butyrylcholinesterase and Intravenously Administered Cocaine in Recreational Cocaine Users.

UNLABELLED: Cocaine dependence presents a major public health issue, and to date, no pharmacotherapies are approved for its treatment. TV-1380 is a novel recombinant albumin-fused mutated butyrylcholinesterase (Albu-BChE) that has increased catalytic efficiency for cocaine compared with wild-type BChE and therefore has the potential to facilitate abstinence in cocaine-dependent subjects by decreasing exposure to cocaine and its reinforcing effects. METHODS: This randomized, double-blind, placebo-controlled, parallel-group study in nondependent cocaine users was conducted to evaluate the effect of a single intramuscular dose of Albu-BChE (50, 100, and 300 mg) on the pharmacokinetic and metabolic profile of intravenous cocaine infusions (40 mg) administered at baseline and at 24, 96, and 168 hours after Albu-BChE dosing, to assess safety of coadministering Albu-BChE and cocaine, and to explore the subjective responses to cocaine infusions after Albu-BChE dosing. RESULTS: Administration of Albu-BChE resulted in significant dose-dependent reductions in cocaine exposure (maximum concentration, area under the curve) and half-life. Effects were greatest at 24 hours after Albu-BChE dose, but were sustained up to 168 hours. Spearman correlations indicated a significant negative relationship between Albu-BChE concentration and cocaine clearance and exposure. Consistent with its mechanism of action, Albu-BChE also shifted cocaine metabolism toward preferential formation of ecgonine methyl ester. Administration of Albu-BChE was associated with modest decreases in subjective reports of feeling high and willingness to take cocaine again after cocaine infusion. Coadministration of Albu-BChE and cocaine was safe and well tolerated. CONCLUSIONS: Administration of Albu-BChE at single doses of 50, 100, and 300 mg safely resulted in long-lasting decreases in cocaine exposure in recreational cocaine users.

Assessment of the abuse liability of a dual orexin receptor antagonist: a crossover study of almorexant and zolpidem in recreational drug users.

BACKGROUND: Dual orexin receptor antagonists (DORAs) enable initiation and maintenance of sleep in patients with primary insomnia. Blockade of the orexin system has shown reduction of drug-seeking behavior in animal studies, supporting the role of orexin antagonism as a novel approach for treating substance abuse. Since hypnotics are traditionally associated with misuse, a lack of abuse liability of DORAs would offer significant benefits over current therapies for sleep disorders. METHODS: In this randomized, crossover, proof-of-concept study, single oral doses of the DORA almorexant (200, 400, and 1,000 mg) were administered to healthy subjects with previous non-therapeutic experience with central nervous system depressants and were compared with placebo and single oral doses of zolpidem (20 and 40 mg), a benzodiazepine-like drug. Subjective measures of abuse potential (visual analog scales [VAS], Addiction Research Center Inventory, and Subjective Drug Value) and objective measures (divided attention [DA]) were evaluated over 24 h post-dose in 33 evaluable subjects. RESULTS: Drug Liking VAS peak effect (E max; primary endpoint) was significantly higher for all doses of almorexant and zolpidem compared with placebo (p<0.001). Almorexant 200 mg showed significantly less 'Drug Liking' than both zolpidem doses (p<0.01), and almorexant 400 mg had smaller effects than zolpidem 20 mg (p<0.05), while almorexant 1,000 mg was not different from either zolpidem dose. Results were similar for other subjective measures, although almorexant generally showed smaller negative and perceptual effects compared with zolpidem. Almorexant also showed less cognitive impairment compared with zolpidem on most DA endpoints. CONCLUSION: This study in humans investigating single doses of almorexant is the first to explore and show abuse liability of a DORA, a class of compounds that is not only promising for the treatment of sleep disorders, but also of addiction.

Human abuse potential and cognitive effects of taranabant, a cannabinoid 1 receptor inverse agonist: a randomized, double-blind, placebo- and active-controlled, crossover study in recreational polydrug users.

INTRODUCTION: Taranabant is a cannabinoid 1 receptor inverse agonist that was in development for treatment of obesity. Because of central nervous system effects, the study was performed to assess the abuse potential and cognitive effects of taranabant in recreational polydrug users compared with phentermine, dronabinol, and placebo. METHODS: Stimulant- and cannabis-experienced polydrug users (N = 30) were randomized in a double-blind crossover study to receive taranabant 2, 4, 10, and 20 mg; phentermine 45 and 90 mg; dronabinol 20 mg; and placebo. Subjective and neurocognitive measures were administered for 24 hours, and peak/peak change from baseline effects were analyzed using a linear mixed-effects model. RESULTS: Phentermine 45 and 90 mg showed abuse-related subjective effects versus placebo, including drug liking, overall drug liking, and other positive/stimulant effects, whereas dronabinol 20 mg showed abuse-related positive, cannabis-like, and sedative effects. Taranabant was not significantly different from placebo on most of the subjective measures other than negative/dysphoric effects at the highest dose, and its effects were significantly less pronounced relative to phentermine and dronabinol on most measures. Phentermine improved cognitive/motor performance and dronabinol impaired motor/cognitive performance on some measures, whereas taranabant 4 and 20 mg had minor impairment effects on manual tracking. CONCLUSIONS: The phentermine and dronabinol results demonstrate the validity and sensitivity of the study. Taranabant did not consistently show stimulant/cannabis-like effects or abuse potential in recreational polydrug users, indicating that cannabinoid 1 receptor inverse agonists/antagonists are unlikely to be recreationally abused.

Positive and negative subjective effects of extended-release oxymorphone versus controlled-release oxycodone in recreational opioid users.

OBJECTIVE: To compare the subjective effects of oxymorphone extended release (OM-ER) versus oxycodone controlled release (OC-CR). DESIGN: Randomized, double-blind, crossover study. SETTING: Inpatient unit. SUBJECTS: Healthy, nondependent recreational opioid users. INTERVENTIONS: Single intact oral tablets that were placebo or contained OM-ER (15 and 30 mg) or OC-CR (30 and 60 mg). Doses were representative of mid-range doses for chronic pain and were calculated using an established opioid conversion table. MAIN OUTCOME MEASURES: Visual Analog Scales, Subjective Drug Value (SDV), and Addiction Research Center Inventory (ARCI) measured positive, negative, and balance effects and pupillometry. Equianalgesic comparisons were between OM-ER 15 mg versus OC-CR 30 mg (low doses) and OM-ER 30 mg versus OC-CR 60 mg (high doses). RESULTS: Thirty-five subjects received all five treatments. Positive subjective effects were lower for OM-ER 15 mg versus OC-CR 30 mg and for OM-ER 30 mg versus OC-CR 60 mg in ARCI Morphine Benzedrine Group (< or = 0.01 for both), Good Effects (p < 0.001 for both), Rush (p < 0.001 for both), and High VAS (p < 0.001 for both). Nausea was higher with OC-CR (p < or = 0.02), and Bad Effects were higher for OC-CR 60 mg versus OM-ER 30 mg (p < 0.001). Balance effects were lower for OM-ER versus OC-CR (Drug Liking, p < 0.001; Overall Drug Liking, p < or = 0.006; SDV, p < or = 0.008), except for Take Drug Again (p < 0.001 for OC-CR 30 mg versus OM-ER 15 mg; p = 0.18 for high-dose group). Euphoric mood, nausea, somnolence, vomiting, and dizziness were more common with OC-CR than OM-ER. LIMITATIONS: Single-dose design; use of healthy, recreational opioid users. CONCLUSIONS: At equianalgesic doses, single oral intact OM-ER produced lower positive, negative, and balance subjective effects than OC-CR, indicating that analgesic potency may not necessarily be reflected in subjective/objective effects.

Reduced cognitive and psychomotor impairment with extended-release oxymorphone versus controlled-release oxycodone.

BACKGROUND: Opioids provide effective pain control, yet have risks including adverse events (AEs) (e.g., constipation, nausea/vomiting, sedation) and cognitive/psychomotor effects. OBJECTIVE: To compare cognitive and psychomotor effects of oxymorphone extended release (OM-ER) versus oxycodone controlled release (OC-CR). STUDY DESIGN: Randomized, double-blind, 5-way crossover SETTING: Single inpatient research unit METHODS: Nondependent recreational opioid users were administered single intact oral tablets of placebo, OM-ER (15 and 30 mg), and OC-CR (30 and 60 mg), separated by a 7- to 21-day washout. The divided attention (DA) test measured psychomotor impairment (e.g., manual tracking [e.g., percentage over road], target accuracy [e.g., target hits], reaction time [hit latency]). Visual analog scales measured alertness/drowsiness, agitation/relaxation, and dizziness. Sedative, stimulant, and dysphoric effects were measured using the Addiction Research Center Inventory Pentobarbital-Chlorpromazine-Alcohol (PCAG), Benzedrine Group (BG), and Lysergic Acid Diethylamide (LSD) scales, respectively. Comparisons were made between equianalgesic doses (OM-ER 15 mg vs OC-CR 30 mg; OM-ER 30 mg vs OC-CR 60 mg), within active drug doses, and between active drugs and placebo using least squares (LS) mean difference of the peak maximum (Emax) or minimum (Emin) effect using linear mixed model analysis of covariance. RESULTS: Thirty-five participants received all 5 treatments. Peak cognitive and psychomotor impairment (LS mean [SE]) was less with OM-ER than equianalgesic doses of OC-CR for reaction time (Emax hit latency, longer if impaired; 571.2 [13.4] vs 588.1 ms [13.4], P=0.03 for OM-ER 15 mg vs OC-CR 30 mg, respectively; 572.4 [13.4] vs 604.3 ms [13.4], P=0.03 for OM-ER 15 mg vs OC-CR 30 mg, respectively; 572.4 [13.4] vs 604.3 ms [13.4], P<0.001 for OM-ER 30 mg vs OC-CR 60 mg, respectively); tracking accuracy (Emin percentage over road, lower if impaired; 71.4 [2.4] vs 65.3 [2.4], P=0.007; 69.9 [2.4] vs 59.4 [2.4], P<0.001), and target accuracy (Emin target hits percentage, lower if impaired; 81.0 [3.1] vs 74.5 [3.1], P=0.02; 79.4 [3.1] vs 66.1 [3.1], P<0.001). Several other DA measures showed that OC-CR, especially 60 mg, produced more psychomotor impairment than equianalgesic OM-ER. Compared to OM-ER, OC-CR produced more dizziness (Emax, P<0.001 for OM-ER 15 mg vs OC-CR 30 mg and for OM-ER 30 mg vs OC-CR 60 mg), drowsiness (Emax, P<0.001 for both equianalgesic dose groups), relaxation (Emin, P=0.003 for OM-ER 15 mg vs OC-CR 30 mg; P=0.001 for OM-ER 30 mg vs OC-CR 60 mg), dysphoria (Emax LSD, P<0.001 for both equianalgesic dose groups), and sedation (Emax, PCAG; P<0.001 for both equianalgesic dose groups) and less stimulation (BG, Emin; P=0.01 for OM-ER 15 mg vs OC-CR mg; P<0.001 for OM-ER 30 mg vs OC-CR 60 mg). Several AEs occurred more commonly with OC-CR than OM-ER (e.g., euphoria, nausea, somnolence, vomiting, dizziness). LIMITATIONS: Participants were young, healthy volunteer nondependent recreational drug users, and only single doses were evaluated. The effects of tampering or higher doses were not assessed. CONCLUSION: Single oral intact low and high doses of OM-ER produced less cognitive and psychomotor impairment plus less sedation than equianalgesic OC-CR in this exploratory study. ClinicalTrials.gov registration NCT00955110.

A one-year economic evaluation of six alternative strategies in the management of uninvestigated upper gastrointestinal symptoms in Canadian primary care.

BACKGROUND: The cost-effectiveness of initial strategies in managing Canadian patients with uninvestigated upper gastrointestinalsymptoms remains controversial. OBJECTIVE: To assess the cost-effectiveness of six management approaches to uninvestigated upper gastrointestinal symptoms in the Canadian setting. METHODS: The present study analyzed data from four randomized trials assessing homogeneous and complementary populations of Canadian patients with uninvestigated upper gastrointestinal symptoms with comparable outcomes. Symptom-free months, qualityadjusted life-years (QALYs) and direct costs in Canadian dollars of two management approaches based on the Canadian Dyspepsia Working Group (CanDys) Clinical Management Tool, and four additional strategies (two empirical antisecretory agents, and two prompt endoscopy) were examined and compared. Prevalence data, probabilities, utilities and costs were included in a Markov model, while sensitivity analysis used Monte Carlo simulations. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves were determined. RESULTS: Empirical omeprazole cost $226 per QALY ($49 per symptom-free month) per patient. CanDys omeprazole and endoscopy approaches were more effective than empirical omeprazole, but more costly. Alternatives using H2-receptor antagonists were less effective than those using a proton pump inhibitor. No significant differences were found for most incremental cost-effectiveness ratios. As willingness to pay (WTP) thresholds rose from $226 to $24,000 per QALY, empirical antisecretory approaches were less likely to be the most costeffective choice, with CanDys omeprazole progressively becoming a more likely option. For WTP values ranging from $24,000 to $70,000 per QALY, the most clinically relevant range, CanDys omeprazole was the most cost-effective strategy (32% to 46% of the time), with prompt endoscopy-proton pump inhibitor favoured at higher WTP values. CONCLUSIONS: Although no strategy was the indisputable cost effective option, CanDys omeprazole may be the strategy of choiceover a clinically relevant range of WTP assumptions in the initial management of Canadian patients with uninvestigated dyspepsia.

Esomeprazole 40 mg once a day in patients with functional dyspepsia: the randomized, placebo-controlled "ENTER" trial.

OBJECTIVE: The etiologies of functional dyspepsia (FD) are unclear, but in some studies, treatment with a proton pump inhibitor has been beneficial. The objective of this study was to evaluate the efficacy of esomeprazole 40 mg once a day compared to placebo in achieving symptom relief in primary care patients with FD. METHODS: This was a randomized, placebo-controlled trial in adult FD patients, who had at least moderate severity of symptoms, defined as a score of > or =4 on a 7-point Global Overall Symptom (GOS) scale. Patients were excluded if they had predominant symptoms of heartburn or regurgitation; after a normal baseline endoscopy, patients were randomized to esomeprazole 40 mg once daily or placebo for 8 wk. The primary outcome measure was symptom relief (GOS < or =2) at 8 wk. RESULTS: Of the 502 enrolled patients, 224 were randomized. The main reasons for exclusion were abnormal endoscopic findings, especially esophagitis. A significantly greater proportion of patients in the esomeprazole group achieved symptom relief at 4 but not at 8 wk compared to placebo: 4 wk esomeprazole 50.5% versus placebo 32.2%, p= 0.009; 8 wk esomeprazole 55.1% versus placebo 46.1%, p= 0.16. A similar relationship at 4 and 8 wk was seen for symptom resolution (GOS = 1) and improvement (DeltaGOS > or =2). CONCLUSION: For the primary outcome measure of symptom relief at 8 wk, there was no statistically significant difference between esomeprazole 40 mg once a day and placebo. However, at 4 wk, esomeprazole was significantly more effective than placebo for symptom relief. The difference in therapeutic gain between 4 and 8 wk was largely due to a higher placebo response rate at 8 wk.

Validation of a short questionnaire in English and French for use in patients with persistent upper gastrointestinal symptoms despite proton pump inhibitor therapy: the PASS (Proton pump inhibitor Acid Suppression Symptom) test.

BACKGROUND: The management of persistent symptoms during acid suppression therapy in patients with gastroesophageal reflux disease or dyspepsia might be improved if patient-physician communication regarding the presence and character of these persistent symptoms were facilitated. AIM: To validate a short, simple questionnaire (the Proton pump inhibitor [PPI] Acid Suppression Symptom [PASS] test), in English and French, to identify patients with persistent acid-related symptoms during PPI therapy and document their response to a change in therapy. METHODS: Patients with persistent acid-related symptoms on PPI therapy were interviewed to produce a draft, five-item questionnaire; content validity was evaluated by focus groups comprising English- and French-speaking patients. Psychometric validity was subsequently evaluated in a multicentre, family practice-based study of English- and French-speaking patients with persistent acid-related upper gastrointestinal symptoms despite PPI therapy. The PASS test, Global Overall Symptom scale, Gastrointestinal Symptom Rating Scale (GSRS), Quality of Life in Reflux and Dyspepsia questionnaire and Reflux Disease Questionnaire were completed at baseline and repeated after one week while patients continued their original PPI therapy. All patients then received esomeprazole 40 mg once daily for four weeks, after which all questionnaires and an evaluation of overall treatment effect were completed. RESULTS: Content validity was established in 20 English- and 16 French-speaking patients. Psychometric validation in 158 English- and 113 French-speaking patients revealed good-to-excellent test-retest reliability coefficients: 0.76 for English; 0.68 for French. For construct validity, the PASS test showed moderate-to-high correlation with the GSRS scale (0.51 for English; 0.43 for French). After four weeks of therapy, the PASS test score fell to zero in 30% of English- and 33% of French-speaking patients, while the Global Overall Symptom score fell to one (no symptoms) in 32% of patients (English- and French-speaking); the PASS test demonstrated good responsiveness in comparison with the GSRS, Reflux Disease Questionnaire and Quality of Life in Reflux and Dyspepsia questionnaire. CONCLUSION: The five-item PASS test is a valid tool for the evaluation of persistent acid-related symptoms in patients receiving PPI therapy. It demonstrates good content validity, test-retest reliability, responsiveness and construct validity in both English and French forms. The PASS test is a simple, clinically applicable tool for the identification of patients with persistent acid-related symptoms during therapy and the assessment of their responses to a change in therapy.