Utility of a controlled amphetamine withdrawal paradigm among adults who use methamphetamine: A pilot clinical trial

BACKGROUND

The continued increase in prevalence of methamphetamine use in the United States has resulted in a significant increase in the number of patients entering treatment for methamphetamine use. However, no robustly efficacious pharmacologic treatment for methamphetamine use or withdrawal has been identified to date after stopping methamphetamine use.

AIMS

Given the association between methamphetamine withdrawal and relapse during early treatment, this study tested a controlled d-amphetamine withdrawal paradigm among methamphetamine-using individuals.

METHODS

Treatment-seeking adults who used methamphetamine (N = 34; 47% female; 100% white) were enrolled in a 4-week, randomized, double-blind, placebo-controlled trial in a residential setting, in which all participants were maintained on d-amphetamine (30 mg BID) during week 1, then half were switched to placebo during weeks 2-3. All participants received placebo during week 4. Outcomes included vital signs, withdrawal, cravings for methamphetamine, mood, and cognition. Bivariate analyses tested treatment group differences on baseline demographic and outcome variables. Repeated measures models examined main and interaction effects of treatment over time.

RESULTS/OUTCOMES

Participants were successfully randomized and safely stabilized on d-amphetamine. Craving for methamphetamine increased during weeks 2-3 in the placebo group relative to those on d-amphetamine. Interactions with age and heart rate were noted.

CONCLUSIONS/INTERPRETATION

To our knowledge, this is the first double-blind, placebo-controlled trial measuring pharmacologic effects of abruptly stopping controlled d-amphetamine administration in adults who use methamphetamine. Results support the potential of this withdrawal paradigm to further examine the efficacy of pharmacologic agents in ameliorating methamphetamine withdrawal symptoms.

Development and validation of a rapid liquid chromatography/tandem mass spectrometry method to quantitate gabapentin and buprenorphine in human serum

RATIONALE

Gabapentin has shown initial promise as an opioid-sparing medication in pain patients as well as a treatment for opioid withdrawal and liquid chriomatography/tandem mass spectrometry (LC/MS/MS) is often used for clinical monitoring. Despite reports of validated tandem mass spectrometric methods for the determination of gabapentin and buprenorphine, mechanisms for the collision-induced fragmentation have not been adequetely described.

METHODS

A rapid analytical method has been developed to determine gabapentinoid, gabapentin, and the partial opioid agonist, buprenorphine, in 20 μL of human serum using LC/MS/MS with a chromatographic run time of 2 min. A simplified sample cleanup procedure using methanol precipitation of serum proteins/lipids followed by evaporation and reconstitution in mobile phase was demonstrated. Gabapentin and buprenorphine were detected following positive ion electrospray ionization using multiple-reaction monitoring. The internal standard approach was used for quantitation with labeled gabapentin-D10 and buprenorphine-D4 serving as internal standards. Using organic reaction principals and stable isotope labels, collision-induced fragmentation mechanisms for both gabapentin and buprenorphine are proposed. The method was validated according to the FDA Guidance for Industry - Bioanalytical Method Validation.

RESULTS

Accuracy was demonstrated by error values ≤15% for buprenorphine and ≤6% for gabapentin. The inter-day precision was ≤4.88% and 15.59% for gabapentin and buprenorphine and the intra-day precision was ≤5.20% and 11.65% for gabapentin and buprenorphine. The lower limit of quantitation corresponded to 10 ng/mL for gabapentin and 1 ng/mL for buprenorphine in serum. Recoveries were 104 ± 2.55% and 85 ± 2.03% for gabapentin and buprenorphine, respectively.

CONCLUSIONS

Concentrations of gabapentin and buprenorphine were determined for five authentic human serum samples to further validate the utility of the method and applicable to therapeutic drug monitoring beyond its use as a drug screening assay. Furthermore, new mechanisms for the collision-induced dissociation of gabapentin and buprenorphine have been proposed.

Telemedicine Interest for Routine Follow-Up Care Among Neurology Patients in Arkansas

BACKGROUND

Teleneurology in Arkansas has been used primarily for management of acute stroke with a state-funded hub-and-spoke model allowing physicians at rural hospitals to access vascular neurologists in time to facilitate tissue plasminogen activator administration. Routine neurologic care has been provided only in small pilot studies. We wished to determine patient interest in participating in teleneurology for routine follow-up visits as well as demographic and medical factors associated with interest.

MATERIALS AND METHODS

New and established patients of the Neurology Outpatient Clinic at the University of Arkansas for Medical Sciences (UAMS) were surveyed between March 2011 and December 2012 to assess their interest in participating in teleneurology as well as potential factors associated with their interest.

RESULTS

Of 1,441 respondents, 52.4% were interested in telemedicine. Of those interested versus uninterested in telemedicine, respectively, 68.9% versus 36.32% traveled more than 1 h to the clinic, 64.7% versus 35.3% had difficulty secondary to neurological conditions, 22.6% versus 6.8% had missed medical appointments due to travel problems, and 43.1% versus 9.4% had travel-imposed financial hardship.

CONCLUSIONS

Telemedicine interest for routine follow-up visits was strong among patients at the UAMS Neurology Outpatient Clinic. Factors positively associated with interest included long travel distances, travel expenses, and transportation difficulties. These results suggest that implementing a telemedicine program for follow-up visits would be acceptable to neurology patients for routine ongoing care.

Effects of prototypic calcium channel blockers in methadone-maintained humans responding under a naloxone discrimination procedure

Accumulating evidence suggests that L-type calcium channel blockers (CCBs) attenuate the expression of opioid withdrawal and the dihydropyridine L-type CCB isradipine has been shown to block the behavioral effects of naloxone in opioid-maintained humans. This study determined whether two prototypic L-type CCBs with differing chemical structures, the benzothiazepine diltiazem and the phenylalkamine verapamil, attenuate the behavioral effects of naloxone in methadone-maintained humans trained to distinguish between low-dose naloxone (0.15 mg/70 kg, i.m.) and placebo under an instructed novel-response drug discrimination procedure. Once discrimination was acquired, diltiazem (0, 30, 60, 120 mg) and verapamil (0, 30, 60, 120 mg), alone and combined with the training dose of naloxone, were tested. Diltiazem alone produced 33-50% naloxone- and novel-appropriate responding at 30 and 60 mg and essentially placebo-appropriate responding at 120 mg. Verapamil alone produced 20-40% naloxone- and 0% novel-appropriate responding. Diltiazem at 60 mg decreased several ratings associated with positive mood and increased VAS ratings of "Bad Drug Effects" relative to placebo, whereas verapamil increased ratings associated with euphoria. When administered with naloxone, diltiazem produced 94-100% naloxone-appropriate-responding with 6% novel-appropriate responding at 60 mg (n=3). When administered with naloxone, verapamil produced 60-80% naloxone- and 0% novel-appropriate responding (n=5). Diltiazem decreased diastolic blood pressure and heart rate whereas verapamil decreased ratings of arousal relative to placebo. These results suggest that CCBs with different chemical structures can be differentiated behaviorally, and that diltiazem and verapamil do not attenuate the discriminative stimulus effects of naloxone in humans at the doses tested.

Sertraline delays relapse in recently abstinent cocaine-dependent patients with depressive symptoms

AIMS

Whether the selective serotonin re-uptake inhibitor sertraline at 200 mg/day delays relapse in recently abstinent cocaine-dependent individuals.

DESIGN

The study involved a 12-week, double-blind, placebo-controlled clinical trial with 2-week residential stay followed by 10-week out-patient participation.

SETTING

Veterans Affairs residential unit and out-patient treatment research program.

PARTICIPANTS

Cocaine-dependent volunteers (n = 86) with depressive symptoms (Hamilton score > 15), but otherwise no major psychiatric or medical disorder or contraindication to sertraline.

MEASUREMENTS

Participants were housed on a drug-free residential unit (weeks 1-2) and randomized to receive sertraline or placebo. Participants then participated on an out-patient basis during weeks 3-12 while continuing to receive study medication. Patients participated in a day substance abuse/day treatment program during weeks 1-3 and underwent weekly cognitive behavioral therapy during weeks 4-12. The primary outcome measure was thrice-weekly urine results and the secondary measure was Hamilton Depression scores.

FINDINGS

Pre-hoc analyses were performed on those who participated beyond week 2. Generally, no group differences in retention or baseline characteristics occurred. Sertraline patients showed a trend towards longer time before their first cocaine-positive urine ('lapse', χ(2) = 3.67, P = 0.056), went significantly longer before having two consecutive urine samples positive for cocaine ('relapse', χ(2) = 4.03, P = 0.04) and showed significantly more days to lapse (26.1 ± 16.7 versus 13.2 ± 10.5; Z = 2.89, P = 0.004) and relapse (21.3 ± 10.8 versus 32.3 ± 14.9; Z = 2.25, P = 0.02). Depression scores decreased over time (F = 43.43, P < 0.0001), but did not differ between groups (F = 0.09, P = 0.77).

CONCLUSIONS

Sertraline delays time to relapse relative to placebo in cocaine-dependent patients who initially achieve at least 2 weeks of abstinence.

Characterizing methamphetamine withdrawal in recently abstinent methamphetamine users: a pilot field study

BACKGROUND

Methamphetamine dependence has become a significant problem, but methamphetamine withdrawal symptoms have not been well studied.

METHODS

This prospective observational pilot study was designed to examine withdrawal symptoms, mood, anxiety, cognitive function, and subjective measures of sleep over a 4-week period in six patients entering residential treatment for methamphetamine dependence.

RESULTS

Methamphetamine withdrawal symptoms, mood, and anxiety symptoms all resolve fairly quickly within 2 weeks of cessation of methamphetamine. Sleep was disrupted over the course of the 4-week study. No clinically significant alterations in blood pressure or heart rate were identified. This study did not demonstrate any alterations in cognitive function over the 4 weeks of the residential stay.

CONCLUSIONS

This pilot study points toward the need for a double-blind, placebo-controlled amphetamine withdrawal paradigm in humans where changes in sleep, cognitive function, and withdrawal measures can be explored more fully.

SCIENTIFIC SIGNIFICANCE

This study extends the literature by pointing toward a methamphetamine withdrawal syndrome that includes alterations in measures of sleep quality and refreshed sleep, early improvement in depression and anxiety symptoms, most striking during the first week, but persisting into the second week.

Randomized, double blind, placebo-controlled trial of disulfiram for the treatment of cocaine dependence in methadone-stabilized patients

This study examined the dose-related efficacy of disulfiram for treating cocaine dependence in methadone-stabilized cocaine dependent participants.

DESIGN

One hundred and sixty-one cocaine- and opioid-dependent volunteers were entered into a 14-week, double blind, randomized, placebo-controlled clinical trial at two sites.

METHODS

Participants were stabilized on methadone during weeks 1-2 and received disulfiram at 0, 62.5, 125 or 250 mg/day during weeks 3-14. All participants also received weekly cognitive behavioral therapy. Thrice-weekly urine samples and weekly self-reported drug use assessments were obtained.

RESULTS

Baseline subject characteristics, retention and drug use did not differ across groups. Outcome analyses were performed on those who participated beyond week 2. Opioid-positive urine samples and self-reported opioid use did not differ by treatment group. The prevalence of alcohol use was low prior to and during the trial and did not differ by treatment group. Cocaine-positive urines increased over time in the 62.5 and 125 mg disulfiram groups and decreased over time in the 250 mg disulfiram and placebo groups (p < 0.0001). Self-reported cocaine use increased in the 125 mg disulfiram group relative to the other three treatment groups (p = 0.04).

CONCLUSIONS

Disulfiram may be contraindicated for cocaine dependence at doses <250 mg/day. Whether disulfiram at higher doses is efficacious in reducing cocaine use in dually cocaine and opioid dependent individuals needs to be determined.

Effect of PTSD diagnosis and contingency management procedures on cocaine use in dually cocaine- and opioid-dependent individuals maintained on LAAM: a retrospective analysis

This randomized clinical trial retrospectively examined the effect of post-traumatic stress disorder (PTSD) and contingency management (CM) on cocaine use in opioid and cocaine dependent individuals maintained on high or low-dose LAAM randomly assigned to CM or a yoked-control condition. Cocaine-positive urines decreased more rapidly over time in those without PTSD versus those with PTSD in the noncontingency condition. In participants with PTSD, CM resulted in fewer cocaine-positive urines compared to the noncontingent condition. This suggests that CM may help improve the potentially worse outcomes in opioid- and cocaine-dependent individuals with PTSD compared to those without PTSD. (Am J Addict 2010;00:1-9).

Behavioral effects of gamma-hydroxybutyrate in humans

Despite the therapeutic use and abuse potential of gamma-hydroxybutyrate (GHB or Xyrem), relatively few studies have examined the behavioral effects of GHB in humans under controlled laboratory conditions. Thus, this eight-session study examined in 10 non-substance-abusing volunteers the behavioral effects of GHB at each of the following doses: 0, 0.32, 0.56, 0.75, 1.0, 1.8, 2.4, 3.2 g/70 kg, orally. Order of dose testing was random, except that the first two participants received active doses in ascending order and 2.4 g/70 kg was always tested before 3.2 g/70 kg. Before drug administration and at several postdrug time points, self-report, observer report, physiological, and psychomotor performance measures were obtained. Analyses based on area under the curve showed that GHB produced dose-related increases in subjective ratings of sedative-like, stimulant-like, positive mood, and dissociative effects, but no changes in psychomotor performance measures or blood pressure. Analyses based on peak effects generally showed dose-related increases in ratings indicating sedative-like, dissociative, and drug liking, although some measures showed U-shaped dose-related changes. These initial findings suggest that GHB at doses of 0.32-3.2 g/70 kg produces dissociative, sedating and some stimulant-like effects in humans without a history of sedative abuse.

Sex and opioid maintenance dose influence response to naloxone in opioid-dependent humans: a retrospective analysis

Pooled self-report and physiological data from 32 male and 15 female methadone or levo-alpha-acetyl methadol (LAAM) maintained volunteers were retrospectively analyzed for individual differences in response to naloxone (0.15 mg/70 kg, IM) and placebo at 20 and 40 min post-injection. Males and females were each divided by the median splitmethadone maintenance dose (MMD, in mg/kg body weight) into high and low MMD groups and MMD was used as a factor in the analyses, along with sex, drug, and time post-drug. Females in the low but not high, MMD group showed naloxone-induced increases in ratings on the Antagonist and Mixed-Action sub-scales of the Adjective Rating Scale, and the Lysergic acid diethyl amine (LSD) sub-scale of the Addiction Research Center Inventory at 20 min post-injection. Males in the high MMD group showed significant naloxone-induced increases in scores of these measures at both post-injection time-points. In addition, low MMD subjects showed more short-lived naloxone-induced increases on Visual Analogue Scale (VAS) Bad and Any drug effects ratings than high MMD subjects. These results suggest that those on a lower MMD, especially women, experience a more intense, but short-lived, response to naloxone, whereas those on a higher MMD experience a more modest, but longer-lasting effect.

Progesterone effects on cocaine use in male cocaine users maintained on methadone: a randomized, double-blind, pilot study

Previously, the authors reported that progesterone treatment attenuated reports of cocaine-induced high in male and female cocaine users. In this pilot clinical trial, the authors tested the safety and efficacy of oral progesterone as a treatment for cocaine dependence in methadone-stabilized male cocaine users. This was a 10-week, randomized, double-blind, placebo-controlled trial. Forty-five male methadone-stabilized cocaine users were randomized to receive placebo (n=15) or progesterone (n=30) for 9 weeks. The progesterone dose was gradually increased from 100 mg to 300 mg twice daily by Week 4 and maintained through Week 10. Treatment retention for the clinical trial was 80%, without significant group differences (log rank=2.4, p=.12). Hierarchical linear modeling estimates of obtaining a cocaine positive urine result across 10 weeks showed a very slight reduction in cocaine use for the progesterone group (Z=-2.89, p<.004). The placebo group showed a slight increase in cocaine use from Week 1 to Week 10 (Z=2.72, p<.007). These slopes significantly differed from each other (Z=-3.83, p<.0001). Overall, the placebo group showed significantly lower probability of having a cocaine positive urine result at treatment's end (Weeks 9 and 10) compared with the progesterone group (0.60 vs. 0.73; U=4837, p<.04). These preliminary findings do not support the efficacy of progesterone in male cocaine users. The efficacy of progesterone in female cocaine users remains to be determined in future studies.

Clinical efficacy of gabapentin versus tiagabine for reducing cocaine use among cocaine dependent methadone-treated patients

BACKGROUND

GABAergic medications appear to reduce the reinforcing effects of cocaine by attenuating cocaine-induced dopamine release. This study evaluated gabapentin and tiagabine compared to placebo in reducing cocaine taking behavior.

METHODS

A total of 76 treatment seeking, cocaine dependent, methadone-treated, predominately Caucasian male subjects were randomly assigned to tiagabine 24 mg/day (N=25), gabapentin 2400 mg/day (N=26) or placebo (N=25) in a 10-week double-blind placebo-controlled trial. Study medications were slowly increased to their full dosages by the end of week 5 and maintained through week 10. The primary outcome measure was thrice-weekly drug free urine samples.

RESULTS

Treatment retention was significantly less for the gabapentin group relative to the other groups (log rank=5.29, d.f.=1, p=0.02). The proportion of cocaine-free urine samples during weeks 6-10 was significantly larger in the tiagabine treated group (p<0.05). The longitudinal data showed significant change in thrice-weekly cocaine free urines that reached a greater abstinent rate for the tiagabine treated group (22%) compared to gabapentin (5%) or placebo (13%) treated groups. Mixed-effects ordinal regression models showed a significant tiagabine by time interaction compared to gabapentin (Z=2.48, d.f.=1, p=0.01) and placebo (Z=3.90, d.f.=1, p=0.0001). The gabapentin group did not differ from placebo.

CONCLUSION

Gabapentin showed poor treatment retention and ineffectiveness in reducing cocaine use. Tiagabine significantly reduced cocaine taking behavior compared to placebo or gabapentin among methadone-stabilized cocaine abusers.

Clinical Efficacy of Citalopram Alone or Augmented with Bupropion in Methadone-Stabilized Patients

Despite the success of opiate-agonist therapies such as methadone for the treatment of opiate addiction, treatment response is not complete. This study evaluates the efficacy of citalopram augmented with bupropion in the treatment of illicit opiate use in a methadone-stabilized population. We conducted a 12-week randomized, double-blind, outpatient clinical trial in which 60 subjects were randomized into one of three treatment groups: placebo, citalopram (40 mg/day) plus placebo, or citalopram (40 mg/day) plus bupropion (50 mg/day). The results indicate that neither citalopram nor citalopram augmented with bupropion were more effective than placebo in the treatment of opioid abuse.

Cue-induced brain activity changes and relapse in cocaine-dependent patients

This study used functional magnetic resonance imaging (fMRI) to examine the association between brain activation during exposure to cocaine-related cues and relapse to drug use in cocaine-dependent (CD) patients. We imaged 17 CD subjects during a 2-week in-patient stay. The subjects then entered a 10-week outpatient placebo-controlled, double-blind randomized clinical trial where urine toxicologies were assessed three times weekly to calculate the treatment effectiveness score (TES). Worse TES correlated with BOLD activation in the left precentral, superior temporal, and posterior cingulate cortices (PCC), and right middle temporal and lingual cortices (R>0.65; P<0.005). The left PCC activation also distinguished eight nonrelapsers (TES above mean and completed treatment) from nine relapsers. Cocaine-free urines were significantly greater in the nonrelapsers (92%) than in the relapsers (66%), who also remained in treatment for an average of only 3.2 weeks. Self-reports of craving during fMRI did not differ between nonrelapsers and relapsers and did not correlate with TES. Relapse to cocaine abuse was associated with increased activation in the sensory association cortex, the motor cortex, and PCC while viewing images of cocaine-related cues. These results suggest that relapse to cocaine abuse is associated with increased brain activation to cocaine cues in sensory, motor, and cognitive-emotional processing areas. This physiological activation was a better predictor of relapse than subjective reports of craving, and may be a useful target for treatment development.

Six-Month Trial of Bupropion With Contingency Management for Cocaine Dependence in a Methadone-Maintained Population

CONTEXT

No effective pharmacotherapies exist for cocaine dependence, although contingency management (CM) has demonstrated efficacy.

OBJECTIVE

To compare the efficacy of bupropion hydrochloride and CM for reducing cocaine use in methadone hydrochloride-maintained individuals.

DESIGN

This 25-week, placebo-controlled, double-blind trial randomly assigned participants to 1 of 4 treatment conditions: CM and placebo (CMP), CM and 300 mg/d of bupropion hydrochloride (CMB), voucher control and placebo (VCP), or voucher control and bupropion (VCB).

SETTING

Outpatient clinic at the Veterans Affairs Connecticut Healthcare System.

PARTICIPANTS

A total of 106 opiate-dependent, cocaine-abusing individuals.

INTERVENTIONS

All study participants received methadone hydrochloride (range, 60-120 mg). Participants receiving bupropion hydrochloride were given 300 mg/d beginning at week 3. In the CM conditions, each urine sample negative for both opioids and cocaine resulted in a monetary-based voucher that increased for consecutively drug-free urine samples during weeks 1 to 13. Completion of abstinence-related activities also resulted in a voucher. During weeks 14 to 25, only completion of activities was reinforced in the CM group, regardless of sample results. The voucher control groups received vouchers for submitting urine samples, regardless of results, throughout the study.

MAIN OUTCOME MEASURE

Thrice-weekly urine toxicologic test results for cocaine and heroin.

RESULTS

Groups did not differ in baseline characteristics or retention rates. Opiate use decreased significantly, with all treatment groups attaining equivalent amounts of opiate use at the end of the study. In the CMB group, the proportion of cocaine-positive samples significantly decreased during weeks 3 to 13 (P<.001) relative to week 3 and remained low during weeks 14 to 25. In the CMP group, cocaine use significantly increased during weeks 3 to 13 (P<.001) relative to week 3, but then cocaine use significantly decreased relative to the initial slope during weeks 14 to 25 (P<.001). In contrast, by treatment end, the VCB and VCP groups showed no significant improvement in cocaine use.

CONCLUSION

These findings suggest that combining CM with bupropion for the treatment of cocaine addiction may significantly improve outcomes relative to bupropion alone.

Efficacy of dose and contingency management procedures in LAAM-maintained cocaine-dependent patients

Opioid- and cocaine-dependent participants (N=140) were randomly assigned to one of the following in a 12-week clinical trial: LAAM (30, 30, 39 mg/MWF) with contingency management (CM) procedures (LC); LAAM (30, 30, 39 mg/MWF) without CM (LY); LAAM (100, 100, 130 mg/MWF) with CM (HC); LAAM (100, 100, 130 mg/MWF) without CM (HY). Urine samples were collected thrice-weekly. In CM, each urine negative for both opioids and cocaine resulted in a voucher worth a certain monetary value that increased for consecutively drug-free urines. Subjects not assigned to CM received vouchers according to a yoked schedule. Vouchers were exchanged for mutually agreed upon goods and services. Groups generally did not differ on retention and baseline characteristics. Overall opioid use was least in the HC and HY groups; opioid use decreased most rapidly over time in the HC group relative to the HY, LC and LY groups. Overall cocaine use was least in the HC group relative to the HY, LC, and LY groups; cocaine use decreased over time most rapidly in the HC and LY groups. Abstinence from both was greatest in the HC group. Opioid withdrawal symptoms decreased most rapidly in the high-dose groups relative to the low-dose groups. These results suggest that an efficacious maintenance dose is necessary for contingencies to be effective in facilitating both opioid and cocaine abstinence.

Combating opiate dependence: a comparison among the available pharmacological options

Pharmacotherapies for heroin addiction may target opiate withdrawal symptoms, facilitate initiation of abstinence and/or reduce relapse to heroin use either by maintenance on an agonist or antagonist agent. Available agents include opioid agonists, partial opioid agonists, opioid antagonists and alpha 2 -agonists for use during managed withdrawal and long-term maintenance. Experimental approaches combine alpha 2 -agonists with naltrexone to reduce the time of opiate withdrawal and to accelerate the transition to abstinence. Recently, buprenorphine has been introduced in the US for office-based maintenance, with the hope of replicating the success of this treatment in Europe and Australia. Naloxone has been added to buprenorphine in order to reduce its potential diversion to intravenous use, whilst facilitating the expansion of treatment. Although comprehensive substance abuse treatment is not limited to pharmacotherapy, this review will focus on the rationale, indications and limitations of the range of existing medications for detoxification and relapse prevention treatments. The two major goals of pharmacotherapy are to relieve the severity of opiate withdrawal symptoms during the managed withdrawal of the opioid and to prevent relapse to heroin use either after abstinence initiation or after being stabilised on a long-acting opiate agonist, such as methadone.

Desipramine Treatment for Cocaine Dependence in Buprenorphine- or Methadone-treated Patients: Baseline Urine Results as Predictor of Response

The prognostic importance of baseline urines for cocaine was examined in a randomized, placebo-controlled, twelve-week clinical trial in 165 opioid- and cocaine-dependent patients who were treated with desipramine (DMI) in combination with buprenorphine (BUP) or methadone (Meth). Patients with a cocaine-positive urine at baseline (CU+) had significantly fewer cocaine-free urines than those with a negative urine at baseline (CU-neg). The CU+ patients showed a treatment effect of DMI. This DMI effect was significant in patients maintained on BUP but not on Meth.

Isradipine and dextromethorphan in methadone-maintained humans under a naloxone discrimination procedure

In seven methadone-maintained human participants trained to distinguish between a low dose of naloxone (0.15 mg/70 kg, i.m.; i.e., Drug A) and placebo (i.e., Drug B) under an instructed novel-response drug discrimination procedure, the calcium channel blocker isradipine (0-10 mg/70 kg, p.o.; N=7) and the N-methyl-D-aspartic acid (NMDA) receptor antagonist dextromethorphan (0-60 mg/70 kg, p.o.; N=6) were tested each alone and in combination with the training dose of naloxone. Isradipine alone produced some naloxone- and novel-appropriate responding, minimal changes in self-reports and decreases in blood pressure. Dextromethorphan alone produced some novel-appropriate responding and minimal changes in self-reports and vital signs. When combined with naloxone, isradipine significantly attenuated naloxone-occasioned responding, without increasing novel-appropriate responding, and attenuated naloxone-induced increases in opioid receptor antagonist ratings and ratings measuring sedation. Dextromethorphan significantly attenuated naloxone-appropriate responding, increased novel-appropriate responding, and enhanced naloxone's effects on ratings of dysphoric effects. These results suggest that isradipine attenuates and dextromethorphan enhances some of the behavioral effects of naloxone in opioid-dependent humans.

Depression Predicts Higher Rates of Heroin Use on Desipramine with Buprenorphine than with Methadone

The effect of lifetime depression was examined in a randomized clinical trial in 164 opioid- and cocaine-dependent patients who were treated with desipramine in combination with either methadone or buprenorphine. We examined treatment retention, illicit opioid and cocaine use, and depressive symptoms, and found that opioid-free urines at baseline, but not later in treatment, were greater among the depressed than non-depressed patients. Among the depressed patients, depressive symptoms at baseline, but not later in treatment, were greater in patients treated with buprenorphine than methadone. Desipramine did not reduce depressive symptoms more than placebo. Finally, the depressed patients treated with desipramine and buprenorphine showed the least improvement in opioid-free urines, while the non-depressed patients treated with desipramine and methadone had more opioid-free urines than those patients treated with placebo desipramine. Cocaine-free urines showed no association with depression. This poor outcome with desipramine and buprenorphine suggests that this medication combination is not indicated in depressed opioid-dependent patients.

Tiagabine increases cocaine-free urines in cocaine-dependent methadone-treated patients: results of a randomized pilot study

AIMS

We sought to evaluate the safety and efficacy of the GABAergic agent tiagabine in reducing cocaine use among methadone-treated patients.

DESIGN

Ten-week randomized double-blind placebo-controlled trial.

SETTING

Opiate Treatment Research Program, Veteran's Affairs Connecticut Healthcare System in West Haven, Connecticut, USA.

PARTICIPANTS

The participants were 45 cocaine-dependent methadone-treated patients who were predominately Caucasian (75.6%), male (77.8%) and never married (53%) with an average age of 38 years (SD = 6.5).

INTERVENTIONS

Comparison groups received tiagabine 12 mg/day (n = 15), tiagabine 24 mg/day (n = 15) or placebo (n = 15).

MEASURES

Baseline assessments included the Structured Clinical Interview for DSM-IV, the Addiction Severity Index, a urine drug test, self-reported use and opiate withdrawal scales. Urine drug tests were performed thrice weekly.

FINDINGS

Treatment retention was over 80% for all treatment groups. The sample mean (+/- SE) of cocaine-free urines for the first week after study entry and before tiagabine was started was 1.16 (0.19) urines/week. During weeks 9 and 10 cocaine-free urines increased significantly from baseline by 33% with high-dose tiagabine (24 mg/day), by 14% with low-dose tiagabine (12 mg/day) and decreased by 10% with placebo (hierarchical linear model, Z= 2.03; P < 0.05). Self-reported cocaine use also decreased significantly more with active medications than with placebo.

CONCLUSIONS

Tiagabine at 24 mg/day was well tolerated among these methadone-treated patients with only one reporting headache. Tiagabine appears to be a promising GABAergic medication that moderately improves cocaine-free urines.

D-cycloserine-Naloxone interactions in opioid-dependent humans under a novel-response naloxone discrimination procedure

Six participants currently in opioid maintenance treatment were trained to distinguish between naloxone (0.15 mg/70 kg, intramuscularly [i.m.]) and placebo under an instructed novel-response drug-discrimination procedure. Doses of the partial glycine agonist D-cycloserine (0-500 mg/70 kg, per os [P.O.]) alone and combined with naloxone (0.15 mg/70 kg) were then tested. D-cycloserine alone produced minimal drug-appropriate responding, no significant changes in self-reported effects, and increases only in systolic blood pressure. When combined with the naloxone, D-cycloserine partially attenuated naloxone-appropriate responding. D-cycloserine attenuated naloxone-induced increases in visual analog scale ratings of "like naloxone" and scores on the Lysergic Acid Diethyl Amide subscale of the Addiction Research Center Inventory (D. R. Jasinski, 1977; W. R. Martin, J. W. Sloan, J. D. Sapiro, & D. R. Jasinski, 1971). Naloxone attenuated D-cycloserine-induced increases in systolic blood pressure. These results suggest that D-cycloserine at doses up to 500 mg/70 kg may have some limited usefulness in relieving symptoms of opioid withdrawal.

Comorbid Major Depressive Disorder as a Prognostic Factor in Cocaine‐Abusing Buprenorphine‐Maintained Patients Treated with Desipramine and Contingency Management

Depression is common among patients who abuse both opiates and cocaine, and its treatment has had mixed success. This study compares buprenorphine-maintained patients with lifetime major depressive disorder (MDD, N = 53) with those never depressed (ND, N = 96) on cocaine and opiate-free urines during a 12-week outpatient double-blind, placebo-controlled, randomized clinical trial. The 149 subjects were assigned to four groups: 1) desipramine (DMI) + contingency management (CM); 2) DMI + noncontingency management (NCM); 3) placebo + CM; and 4) placebo + NCM. Depression assessments included Hamilton Depression Rating Scale, Center for Epidemiological Studies Depression Inventory, and Structured Clinical Interview for DSM-IV interview for diagnosis of lifetime MDD. Urine toxicologies were performed thrice weekly and the CES-D was performed monthly. The MDD group had a larger proportion of females (45% vs 21%, P = 0.02) and were more likely to be married (13.2% vs 7.3%, P = 0.02) than the ND group. Treatment retention did not vary by depression status. Hierarchical Linear Modeling found that depressive symptoms decreased comparably across the four treatment groups. Although participation in CM improved drug-free urines more for patients with MDD than for the ND group (Z = 2.44, P = 0.01), treatment with DMI was significantly more efficacious for the ND group than for the MDD group (Z = -2.89, P = 0.003). These results suggest that patients with MDD may respond better to behavioral treatments such as CM than to desipramine plus buprenorphine. The ND cocaine-abusing, opiate-dependent patients may be more responsive to the anticraving effects of DMI.

Effects of naltrexone and isradipine, alone or in combination, on cocaine responses in humans

Preclinical studies suggested that combination of naltrexone and isradipine may be useful for the treatment of cocaine addiction. This study examined whether naltrexone and isradipine, alone or in combination, would attenuate the subjective and physiological effects of cocaine in humans. Seven cocaine users participated in a randomized, double-blind, placebo-controlled inpatient study. Before each of the seven experimental sessions, subjects were treated orally with naltrexone (50 mg or placebo), isradipine (10 mg or placebo), or naltrexone plus isradipine. Subjects then received a single dose of intranasal cocaine (4 mg or 100 mg/70 kg). Isradipine alone attenuated the systolic blood pressure response to cocaine. In contrast, isradipine plus naltrexone treatment attenuated both the systolic and diastolic blood pressure responses. Naltrexone alone did not affect the blood pressure response to cocaine. For subjective response to cocaine, isradipine, alone or in combination with naltrexone, did not have significant effects. Naltrexone treatment alone attenuated the rating of "good effects" from cocaine without affecting other subjective responses. These results suggest that isradipine alone or in combination with naltrexone attenuates some of the physiological effects of cocaine.

Desipramine and contingency management for cocaine and opiate dependence in buprenorphine maintained patients

Co-dependence on opiates and cocaine occurs in about 60% of patients entering methadone treatment and has a poor prognosis. However, we recently found that desipramine (DMI) could be combined with buprenorphine to significantly reduce combined opiate and cocaine use among these dually dependent patients. Furthermore, contingency management (CM) has been quite potent in reducing cocaine abuse during methadone maintenance. To test the efficacy of combining CM with these medications we designed a 12-week, randomized, double blind, four cell trial evaluating DMI (150 mg/day) or placebo plus CM or a non-contingent voucher control in 160 cocaine abusers maintained on buprenorphine (median 16 mg daily). Cocaine-free and combined opiate and cocaine-free urines increased more rapidly over time in those treated with either DMI or CM, and those receiving both interventions had more drug-free urines (50%) than the other three treatment groups (25-29%). Self reported opiate and cocaine use and depressive and opioid withdrawal symptoms showed no differences among the groups and symptom levels did not correlate with urine toxicology results. Lower DMI plasma levels (average 125 ng/ml) were associated with greater cocaine-free urines. DMI and CM had independent and additive effects in facilitating cocaine-free urines in buprenorphine maintained patients. The antidepressant appeared to enhance responsiveness to CM reinforcement.

Effects of reducing contingency management values on heroin and cocaine use for buprenorphine- and desipramine-treated patients

AIMS

During 3 months where contingency management (CM) had an escalating value for each consecutive drug-free urine (escalating CM), cocaine- and heroin-abusing patients significantly increased drug-free urines. The 'escalating CM' was eliminated during months 4-6 to assess any reduction in drug-free urines.

DESIGN

Patients who completed a 3-month, randomized, double-blind, trial evaluating CM versus non-CM and desipramine (DMI) versus placebo, had an 'escalating CM' eliminated during months 4-6. The CM and non-CM groups were compared using thrice-weekly urine samples.

SETTING

Out-patient buprenorphine maintenance for 6 months.

PARTICIPANTS

All 75 of the 160 original study patients who completed month 3 of the clinical trial.

INTERVENTION

The 'escalating CM' was eliminated for all 3 months and during months 5 and 6 the response requirement was also increased to two and then three consecutive drug-free urines in order to obtain a voucher.

MEASUREMENTS

Urine toxicology for opiates and cocaine.

FINDINGS

After eliminating the 'escalating CM', the CM group showed a decline in combined opioid- and cocaine-free urines. This decline within the CM group was greater in those treated with DMI than placebo.

CONCLUSIONS

Buprenorphine with DMI maintained drug abstinence after eliminating the 'escalating CM', but not after increasing the response requirement, suggesting the need for more intensive psychosocial interventions during CM.

Clonidine and yohimbine in opioid-dependent humans responding under a naloxone novel-response discrimination procedure

Opioid-maintained volunteers were trained to distinguish between a low dose of the opioid antagonist naloxone (0.15 mg/70 kg, i.m.; i.e. Drug A) and placebo (i.e. Drug B), under an instructed novel-response drug discrimination procedure in which subjects identify the drug condition as 'A', 'B', or 'N' (neither A nor B - 'novel'). Once the discrimination was acquired, doses of naloxone, the alpha2-adrenergic antagonist yohimbine, the alpha2-adrenergic agonist clonidine, and the training dose of naloxone in combination with clonidine were tested. Naloxone and yohimbine each produced a dose-related increase and decrease in naloxone- and 'novel'-appropriate responding, respectively, with the naloxone stimulus partially generalizing to yohimbine. Clonidine produced primarily placebo-appropriate responding. Naloxone produced expected changes in self-reports, but effects of yohimbine and clonidine were unremarkable, and yohimbine was never identified as an opioid antagonist. Clonidine partially attenuated naloxone-occasioned responding in a non-dose-related manner, and attenuated some, but not all, naloxone-induced changes in self-report measures. Naloxone attenuated or enhanced several clonidine-induced changes in self-report and physiological measures. These findings indicate that adrenergic mechanisms are involved in the expression of opioid withdrawal, but the involvement is indirect.

Treatment of heroin (diamorphine) addiction: current approaches and future prospects

New pharmacological treatments for heroin (diamorphine) addiction include drugs that reduce opiate withdrawal symptoms and agents that are given during the maintenance phase of treatment. A variety of different types of pharmacological agents (opioid agonists, partial opioid agonists, opioid antagonists and alpha(2)-adrenoreceptor agonists) are reviewed and the evidence of their use during managed withdrawal and maintenance are presented. Experimental approaches attempting to reduce the time of opiate withdrawal and to accelerate the transition to abstinence are being developed. The combination tablet of buprenorphine and naloxone that is to be introduced for office-based maintenance is currently undergoing intense evaluation in the US. This new approach may facilitate the expansion of treatment while reducing the potential for medication diversion and intravenous use.

Utility of crossover designs in clinical trials: efficacy of desipramine vs. placebo in opioid-dependent cocaine abusers

The utility of the crossover design in substance abuse research was examined in a 26-week, double-blind clinical trial that evaluated the efficacy of desipramine (0 or 150 mg/day) in 109 male and female cocaine- and opiate-dependent patients maintained on buprenorphine (12 mg/day) or methadone (65 mg/day). After being stabilized on buprenorphine or methadone (weeks 1-2), half of the patients were randomly assigned to receive desipramine for the first half of the trial and placebo for the second, with the order reversed for the second half. Analyses using hierarchical linear models (HLM) indicated that desipramine reduced the use of opiates only when administered at the start (rather than the middle) of the trial, whereas cocaine use was reduced when desipramine was introduced at either time.

Ketoconazole increases cocaine and opioid use in methadone maintained patients

Stress plays an important role in substance abuse problems. For example, in studies with rodents stress induces reinstatement of opioid and cocaine self-administration. In addition, attenuation of the stress response by pharmacological adrenalectomy using ketoconazole, a cortisol synthesis inhibitor, reduces cocaine self-administration in rodents. In contrast, studies in primates and humans have produced conflicting results using cortisol synthesis inhibitors for attenuating cocaine-related behaviors and subjective effects. To explore the treatment implications of these findings, ketoconazole's (600-900 mg daily) ability to reduce heroin and cocaine use was compared with placebo in 39 methadone maintained patients with a history of cocaine abuse or dependence during a 12-week double blind trial. Contrary to the predicted effects, both heroin and cocaine use increased after patients were stabilized on methadone and ketoconazole. Depressive and withdrawal symptoms improved no more with ketoconazole than with placebo treatment, and side effects were greater on ketoconazole than placebo. As reported before with methadone treatment, morning cortisol levels were significantly lower than normal values throughout the clinical trial, but were not lower with ketoconazole than placebo treatment. Thus, in agreement with the negative results from acute dosing studies in primates and humans, chronic ketoconazole treatment does not appear to reduce cocaine or opioid use in humans maintained on methadone.

Butorphanol and nalbuphine in opioid-dependent humans under a naloxone discrimination procedure

Opioid-maintained volunteers were trained to distinguish between a low dose of the opioid antagonist naloxone (0.15 mg/70 kg, i.m.; i.e., Drug A) and placebo (i.e., Drug B) under an instructed novel-response drug-discrimination procedure in which subjects identify the drug condition as "A," "B," or "N" (neither A nor B--'novel'). Once the discrimination was acquired, doses of naloxone (000.15 mg/70 kg, i.m.) and the mixed-action opioid agonist/antagonists butorphanol (0-1.5 mg/70 kg, i.m.) and nalbuphine (0-3.0 mg/70 kg, i.m.) were tested. Naloxone produced dose-related increases in naloxone-appropriate responding with little or no 'novel'-appropriate responding. Butorphanol produced a dose-related increase in naloxone- and 'novel'-appropriate responding, occasioning approximately 70% and 29%, respectively, at the highest dose tested. Nalbuphine produced 40-65% naloxone-appropriate responding at all doses tested and 33% 'novel'-appropriate responding at the highest doses. Self-reported effects produced by each agent differed only slightly. These results suggest that mixed-action opioid agonist/antagonists may be distinguished from the opioid antagonist naloxone based on their discriminative-stimulus effects under a novel-response naloxone discrimination procedure.

Effects of cocaine prior to and during bupropion maintenance in cocaine-abusing volunteers

The effects of cocaine were examined prior to and during bupropion maintenance in nonopioid-dependent cocaine abusers. Prior to bupropion maintenance, subjects underwent an experimental session during which repeated cocaine doses (0, 50, 100 mg/70 kg) were administered intranasally. Then subjects were maintained on bupropion (150 and 300 mg per day) and underwent experimental sessions as before. Cocaine, regardless of bupropion, produced dose-related increases in several stimulant-like self-reports, performance and cardiovascular measures. Bupropion decreased POMS ratings of friendliness and vigor, regardless of cocaine dose. Bupropion enhanced and attenuated cocaine-induced increases in ratings on the LSD and BG subscales of the ARCI, respectively. These results suggest that bupropion does not alter the acute subjective or cardiovascular effects of cocaine in a robust manner.

Sex differences in self-reported and physiological response to oral cocaine and placebo in humans

Self-report and physiological data from 27 male and 8 female cocaine-abusing volunteers exposed to cocaine (80 mg/70 kg p.o.) and placebo were examined for sex differences in their responses. Females reported significantly greater baseline ratings on the Pentobarbital-Chlorpromazine-Alcohol Group (PCAG) (sedation) and Lysergic Acid Diethylamide (LSD) (dysphoria) subscales of the Addiction Research Center Inventory-Short Form (ARCI) relative to males. In addition, females reported significantly greater ratings on the Visual Analogs Scales (VAS) Bad Drug Effects and Anxious/Nervous scales relative to males, regardless of drug. Cocaine produced greater increase in systolic blood pressure in males following cocaine, whereas females showed greater increases following placebo. These results suggest that a placebo control is necessary to determine sex differences in response to an active drug.

Neurobiological adaptations to psychostimulants and opiates as a basis of treatment development

Abuse of illicit substances, in particular psychostimulants and opiates, is a worldwide public health issue. Chronic use of cocaine and amphetamine causes common neurobiological adaptations that may guide new treatment development. These include perturbations in dopamine and serotonin neurotransmission, leading to trials of antidepressants, and serotonin and dopamine augmentation strategies. The detection of cerebral perfusion abnormalities caused by psychostimulants has led to examination of antiplatelet and excitatory amino acid (EAA) antagonist therapies. Further, development of cocaine vaccines allows for testing of peripheral blockade approaches to cocaine addiction. New approaches to behavioral treatments for cocaine dependence are also reviewed. For opiate dependence, understanding of heroin's effects on mu and kappa opiate receptors has led to investigations of the partial mu agonist buprenorphine in opiate maintenance. Evidence for hyper-excitability of locus coeruleus (LC) noradrenergic neurons and EEA inputs to the LC guides trials of new alpha 2-adrenergic agonists and EEA antagonists to alleviate opiate withdrawal. Finally, clinical experience with withdrawal from methadone and LAAM has led to trials of antagonist-accelerated opiate withdrawal. Improved treatment of psychostimulant and opiate addiction is critically needed, and likely to have wide-reaching impact in health care and society.

Thrice-weekly versus daily buprenorphine maintenance

BACKGROUND

Buprenorphine is a promising alternative to methadone or levo-acetyl alpha methadol for opioid agonist maintenance treatment, and thrice-weekly dosing would facilitate its use for this purpose.

METHODS

After a 3-day induction, opioid-dependent patients (n = 92) were randomly assigned to daily clinic attendance and 12-weeks maintenance treatment with sublingual buprenorphine administered double blind either daily (n = 45; 16 mg/70 kg) or thrice weekly (n = 47; 34 mg/70 kg on Fridays and Sundays and 44 mg/70 kg on Tuesdays). Outcome measures include retention, results of 3x/week urine toxicology tests, and weekly self-reported illicit drug use.

RESULTS

There were no significant differences at baseline in important social, demographic, and drug-use features. Retention was 71% in the daily and 77% in the 3x/week conditions. The proportion of opioid-positive urine tests decreased significantly from baseline in both groups and averaged 57% (daily) and 58% in 3x/week. There were no significant differences between groups in self-reported number of bags of heroin used for any day of the week, including Thursdays (48-72 hours following the last buprenorphine dose for subjects in the 3x/week condition), or in medication compliance (92%, 91%) and counseling attendance (82%, 82%).

CONCLUSIONS

At an equivalent weekly dose of 112 mg/70 kg, thrice-weekly and daily sublingual buprenorphine appear comparable in efficacy with regard to retention and reductions in illicit opioid and other drug use. These findings support the potential for utilizing thrice-weekly buprenorphine dosing in novel settings.

Individual differences in humans responding under a cocaine discrimination procedure: discriminators versus nondiscriminators

Twenty-six cocaine-abusing volunteers were trained to discriminate cocaine (80 mg/70 kg, p.o.) from placebo. On the basis of a discrimination acquisition criterion (i.e., >80% drug-appropriate responding for 4 consecutive sessions within 8-10 sessions), 18 participants were classified as discriminators (Ds) and 8 as nondiscriminators (NDs). Relative to Ds, NDs reported a greater amount of cocaine use per time. During the training phase, NDs showed significantly lower ratings than Ds on a stimulant ratings scale, regardless of the training drug condition. During the test-of-acquisition phase, cocaine-induced increases in scores on ratings of drug strength, anxious-nervous and cocaine high, as well as on a euphoria ratings scale, were significantly greater in Ds than NDs, relative to placebo. These results suggest that drug use history, general arousal level, and drug sensitivity may be important variables influencing the acquisition of cocaine versus placebo discrimination in cocaine abusers.

Individual differences in humans responding under a cocaine discrimination procedure: discriminators versus nondiscriminators

Twenty-six cocaine-abusing volunteers were trained to discriminate cocaine (80 mg/70 kg, p.o.) from placebo. On the basis of a discrimination acquisition criterion (i.e., >80% drug-appropriate responding for 4 consecutive sessions within 8-10 sessions), 18 participants were classified as discriminators (Ds) and 8 as nondiscriminators (NDs). Relative to Ds, NDs reported a greater amount of cocaine use per time. During the training phase, NDs showed significantly lower ratings than Ds on a stimulant ratings scale, regardless of the training drug condition. During the test-of-acquisition phase, cocaine-induced increases in scores on ratings of drug strength, anxious-nervous and cocaine high, as well as on a euphoria ratings scale, were significantly greater in Ds than NDs, relative to placebo. These results suggest that drug use history, general arousal level, and drug sensitivity may be important variables influencing the acquisition of cocaine versus placebo discrimination in cocaine abusers.

Buprenorphine vs methadone maintenance treatment for concurrent opioid dependence and cocaine abuse

BACKGROUND

Buprenorphine, a partial mu-agonist and kappa-antagonist, has been proposed as an alternative to methadone for maintenance treatment of opioid dependence, especially for patients with concurrent cocaine dependence or abuse. This study evaluated whether higher maintenance doses of buprenorphine and methadone are superior to lower doses for reducing illicit opioid use and whether buprenorphine is superior to methadone for reducing cocaine use.

METHODS

A total of 116 subjects were randomly assigned to 1 of 4 maintenance treatment groups involving higher or lower daily doses of sublingual buprenorphine (12 or 4 mg) or methadone (65 or 20 mg) in a double-blind, 24-week clinical trial. Outcome measures included retention in treatment and illicit opioid and cocaine use as determined by urine toxicology testing and self-report.

RESULTS

There were significant effects of maintenance treatment on rates of illicit opioid use, but no significant differences in treatment retention or the rates of cocaine use. The rates of opioid-positive toxicology tests were lowest for treatment with 65 mg of methadone (45%), followed by 12 mg of buprenorphine (58%), 20 mg of methadone (72%), and 4 mg of buprenorphine (77%), with significant contrasts found between 65 mg of methadone and both lower-dose treatments and between 12 mg of buprenorphine and both lower-dose treatments.

CONCLUSIONS

The results support the superiority of higher daily buprenorphine and methadone maintenance doses vs lower doses for reducing illicit opioid use, but the results do not support the superiority of buprenorphine compared with methadone for reducing cocaine use.

Desipramine, amantadine, or fluoxetine in buprenorphine-maintained cocaine users

The clinical efficacy of promising cocaine anti-craving medications was examined in combination with buprenorphine. Twenty-one opioid-dependent cocaine abusers were enrolled in a double-blind, 12-week trial in which they received on a daily basis buprenorphine (8 mg, s.l.) plus either desipramine (150 mg, p.o.), amantadine (300 mg, p.o.), or fluoxetine (60 mg, p.o.). Urine samples and self-reported drug use were obtained 1-3 times/week. The order of greatest patient retention across the 12 weeks was desipramine (83.3%) > amantadine (66.7%) > fluoxetine (20.0%). The desipramine and amantadine groups appeared to have greater increases in opioid- and cocaine-free urines than the fluoxetine group. These results suggest that desipramine and amantadine may facilitate greater opioid and cocaine abstinence than fluoxetine.