Effect of low-energy shock wave therapy on intravesical epirubicin delivery in a rat model of bladder cancer.

OBJECTIVES: To study the efficacy of low-energy shock wave therapy (LESW) on enhancing intravesical epirubicin (EPI) delivery in a rat model of bladder cancer (BCa). MATERIALS AND METHODS: A total of 100 female Fischer rats were randomly allocated into five groups: control; BCa; LESW; EPI; and EPI plus LESW. After BCa induction by N-butyl-N-(4-hydroxybutyl)nitrosamine, EPI (0.6 mg/0.3 mL of EPI diluted in 0.3 mL saline) or saline (0.6 mL) was administered and retained in the bladders for 1 h with or without LESW treatment (300 pulses at 0.12 mJ/mm2 ). This was repeated weekly for 6 weeks. Survival was then calculated, rats were weighed and their bladders were harvested for bladder/body ratio estimation, histopathological examination, p53 immunostaining, miR-210, hypoxia-inducible factor (HIF)-1α, tumour necrosis factor (TNF)-α and interleukin (IL)-6 relative gene expression and fluorescence spectrophotometric drug quantification. Heart and blood samples were also collected for assessment of the safety profile and toxicity. RESULTS: The EPI plus LESW group had significantly lower mortality rates, loss of body weight and bladder/body ratio. Histopathological results in terms of grossly visible bladder lesions, mucosal thickness, dysplasia formation and tumour invasion were significantly better in the combined treatment group. The EPI plus LESW group also had statistically significant lower expression levels of p53 , miR-210, HIF-1α, TNF-α and IL-6. LESW increased urothelial concentration of EPI by 5.7-fold (P < 0.001). No laboratory variable exceeded the reference ranges in any of the groups. There was an improvement of the indicators of EPI-induced cardiomyopathy in terms of congestion, hyalinization and microvesicular steatosis of cardiomyocytes (P = 0.068, 0.003 and 0.046, respectively) in the EPI plus LESW group. CONCLUSIONS: The combined use of intravesical EPI and LESW results in less BCa invasion and less dysplasia formation, as LESW increases urothelial permeability of EPI and enhances its delivery into tumour tissues, without subsequent toxicity.

National Rehabilitation Center programme performance measures in the United Arab Emirates, 2013.

The aim of this study was to measure the performance of the National Rehabilitation Center (NRC) programme and the services it provides. A 6-point tool was developed based on international standards with appropriate performance measures. The elements of the tool were applied to the electronic data files for 2013. The results showed that there were some operational, quality and data system issues. Some items were easily accessible, e.g. capacity, waiting time, family involvement. Others were difficult to sort and find and some were not available in the electronic system and had to be retrieved from other sources, e.g. programme effectiveness. There was a high no-show rate for appointments (46%) and readmission rate (52%) and most families did not attend family sessions (72%). This was a valuable exercise which identified gaps in operations and records. The findings were shared with the different teams to help improve the quality of data and services and the tool will be used for annual performance evaluations.

Selegiline transdermal system (STS) as an aid for smoking cessation.

INTRODUCTION: This study examined the efficacy and safety of selegiline transdermal system (STS) and brief repeated behavioral intervention (BRBI) for smoking cessation in heavy smokers. We hypothesized that the quit rate of subjects who received STS and BRBI would be significantly greater than that of those who received placebo patch and BRBI. METHODS: This was a double-blind, placebo-controlled parallel-group study in which 246 men and women were randomized to receive either STS (n = 121) or placebo patch (n =125) for 9 weeks. Recruitment targeted heavy smokers, defined as individuals with self-reported use of ≥15 cigarettes/day in the 30 days prior to enrollment, who had smoked cigarettes for the past 5 years, and had an expired CO level ≥9 ppm during screening. RESULTS: Although STS was well tolerated, the overall results indicated that STS with BRBI was not more effective than placebo plus BRBI for smoking cessation (p = .58). CONCLUSIONS: The results are discussed in relation to interventions for heavy smokers. Although 2 trials using oral selegiline both showed trends toward improved abstinence, these results indicate that STS with BRBI was not an effective aid for smoking cessation at the end of treatment (10 weeks), 14, or 26 weeks.

Functional and molecular evaluation of using aliskiren during acute and chronic partial ureteral obstruction in rat solitary kidney.

AIMS: To study the effect of direct renin inhibitor (aliskiren) on the renal function during acute and chronic partial ureteral obstruction (PUO) in rat solitary kidney. MAIN METHODS: Sixty male Sprague-Dawley rats were randomly allocated into three groups (20 rats each); sham, PUO and aliskiren groups. Right nephrectomy was performed in all groups. Rats in PUO and aliskiren groups were subjected to left PUO and received no treatment and aliskiren (10 mg/kg, orally, once per day till sacrification), respectively. Blood samples were then collected for biochemical measurements. Ten rats from each group were sacrificed after two weeks, while the remaining rats were sacrificed after four weeks. Left kidneys were harvested for histopathological examination, BCL-2, interleukin (IL)-6, transforming growth factor (TGF)-ß1, collagen I and fibronectin relative gene expression and assessment of glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA) and nitric oxide (NO) activity. KEY FINDINGS: After two and four weeks of PUO, aliskiren significantly recompensed the rise of serum creatinine (Scr) and blood urea nitrogen (BUN). Aliskiren also revealed significantly better histopathological results regarding cortical and medullary necrosis, regeneration and inflammatory cell infiltration. Aliskiren group showed statistically significant up-regulation of BCL-2 and down-regulation of IL-6, TGF-ß1, collagen I and fibronectin relative gene expression. Aliskiren significantly increased GSH and SOD activity and reduced MDA and NO activity. Moreover, aliskiren administration for four weeks after PUO significantly yielded more renoprotective effect compared to its administration for two weeks. SIGNIFICANCE: Aliskiren ameliorates the deterioration of the renal function during acute and chronic PUO in a solitary kidney.

Interventions for HIV and hepatitis C virus infections in recreational drug users.

Recreational drug use and infections are 2 of the major problems in the world today. Both cause serious health problems, such as immunologic impairment leading to opportunistic infections and medical comorbidity, including medical complications associated with, for example, human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections. Effective and safe interventions (prevention and pharmacologic treatment) are possible for drug-dependent patients with single or dual infections with HIV and HCV if patients in drug treatment programs are closely monitored for adherence and compliance to treatment regimens.

Drug interactions between antiretroviral medications and medications used in the treatment of drug addiction: research needs.

Today substance dependence is one of the major public health problems in the world with millions of people abusing legal and illegal drugs. In addition, almost one-third of the world's population suffers with one or more infections. Both drugs of abuse and infections are associated with serious medical and health consequences, some of which may be exacerbated by the occurrence of pharmacokinetic and/or pharmacodynamic interactions between medications used in the treatment of these conditions when they co-occur. This review briefly discusses issues surrounding clinical management related to drug interactions experienced by substance abusing patients. The emphasis of this paper is on the research needed to further study the extent, nature, and underlying molecular/genetic mechanism(s) of interactions between drugs of abuse, medications used in the treatment of drug addiction, and co-occurring infections.

A cholecystokinin B receptor antagonist and cocaine interaction, phase I study.

AIMS: RPR 102681, a cholecystokinin-B antagonist, increased dopamine (DA) release and reduced cocaine self-administration in animals. This pilot study sought to assess the safety and pharmacokinetics (PK) of co-administration of RPR 102681 and cocaine, and to confirm the DA release mechanism of RPR 102681. METHODS: Sixteen cocaine-dependent participants were randomized to either placebo or RPR102681 at 3 ascending doses; cocaine was co-administered at steady state of RPR 102681. [11 C]raclopride positron emission tomography scans were conducted at baseline and at each RPR102681 dose. RESULTS: RPR 102681 was well tolerated, and safe to co-administer with cocaine. RPR 102681 did not alter the PK of either cocaine or its metabolite benzoylecgonine and showed no intrinsic abuse liability. There was a trend toward reduction of cocaine craving scores. In contrast to animal studies, RPR 102681 significantly increased the binding potential of [11 C]raclopride in the ventral striatum (t test, P < .001) and caudate nucleus (t test, P < .0001) in a small subset of patients, suggesting that it may reduce intrasynaptic striatal DA. CONCLUSION: Overall, this pilot study suggests that RPR 102681 would be unlikely candidate, as an agonist medication for the treatment for cocaine addiction but worth investigating further for possible role in reducing craving.

Bupropion for the treatment of methamphetamine dependence.

Bupropion was tested for efficacy in increasing weeks of abstinence in methamphetamine-dependent patients, compared to placebo. This was a double-blind placebo-controlled study, with 12 weeks of treatment and a 30-day follow-up. Five outpatient substance abuse treatment clinics located west of the Mississippi participated in the study. One hundred and fifty-one treatment-seekers with DSM-IV diagnosis of methamphetamine dependence were consented and enrolled. Seventy-two participants were randomized to placebo and 79 to sustained-release bupropion 150 mg twice daily. Patients were asked to come to the clinic three times per week for assessments, urine drug screens, and 90-min group psychotherapy. The primary outcome was the change in proportion of participants having a methamphetamine-free week. Secondary outcomes included: urine for quantitative methamphetamine, self-report of methamphetamine use, subgroup analyses of balancing factors and comorbid conditions, addiction severity, craving, risk behaviors for HIV, and use of other substances. The generalized estimating equation regression analysis showed that, overall, the difference between bupropion and placebo groups in the probability of a non-use week over the 12-week treatment period was not statistically significant (p=0.09). Mixed model regression was used to allow adjustment for baseline factors in addition to those measured (site, gender, level of baseline use, and level of symptoms of depression). This subgroup analysis showed that bupropion had a significant effect compared to placebo, among male patients who had a lower level of methamphetamine use at baseline (p<0.0001). Comorbid depression and attention-deficit/hyperactivity disorder did not change the outcome. These data suggest that bupropion, in combination with behavioral group therapy, was effective for increasing the number of weeks of abstinence in participants with low-to-moderate methamphetamine dependence, mainly male patients, regardless of their comorbid condition.

The SRPHK1 outcome measure for cocaine-dependence trials combines self-report, urine benzoylecgonine levels, and the concordance between the two to determine a cocaine-use status for each study day.

BACKGROUND: There is currently no FDA-approved medication for cocaine dependence and no standard primary outcome measure for reduction of cocaine use in cocaine-dependence trials. The ability to detect a significant medication effect will depend, in part, on the primary outcome measure utilized. The goal of the present paper is to compare self-report or either of two urine toxicology measures used alone to a relatively new measure -- the SRPHK1 -- which combines self-report, quantitative urine benzoylecgonine levels, and an estimate of the concordance between the two to determine the cocaine-use status of each study day. METHOD: Datasets from two separate randomized, placebo-controlled cocaine-dependence trials were used to compare four cocaine-use outcome measures. RESULTS: The two data sets yielded very similar findings and suggest that the combined measure is associated with significantly fewer missing data than urine toxicology and that estimated cocaine use varied significantly depending on which measure was used, with the lowest use estimate being yielded by self-report, the highest by the two urine toxicology measures evaluated, and an intermediate value obtained using the combined measure. The results also suggest that the concordance between self-report and urine toxicology is around 90% at the beginning of the clinical trial but decreases to around 75% by the end of the trial. CONCLUSION: By combining the objectivity of urine toxicology with the reduced incidence of missing data characteristic of self-report, the SRPHK1 may provide advantages over self-report or urine toxicology measures used alone. In any case, the SRPHK1 provides an interesting complement to these other outcome measures and may warrant further evaluation.

A Phase 3 placebo-controlled, double-blind, multi-site trial of the alpha-2-adrenergic agonist, lofexidine, for opioid withdrawal.

CONTEXT: Lofexidine is an alpha-2-adrenergic receptor agonist that is approved in the United Kingdom for the treatment of opioid withdrawal symptoms. Lofexidine has been reported to have more significant effects on decreasing opioid withdrawal symptoms with less hypotension than clonidine. OBJECTIVE: To demonstrate that lofexidine is well tolerated and effective in the alleviation of observationally defined opioid withdrawal symptoms in opioid dependent individuals undergoing medically supervised opioid detoxification as compared to placebo. DESIGN: An inpatient, Phase 3, placebo-controlled, double-blind, randomized multi-site trial with three phases: (1) opioid agonist stabilization phase (days 1-3), (2) detoxification/medication or placebo phase (days 4-8), and (3) post detoxification/medication phase (days 9-11). SUBJECTS: Sixty-eight opioid dependent subjects were enrolled at three sites with 35 randomized to lofexidine and 33 to placebo. MAIN OUTCOME MEASURE: Modified Himmelsbach Opiate Withdrawal Scale (MHOWS) on study day 5 (second opioid detoxification treatment day). RESULTS: Due to significant findings, the study was terminated early. On the study day 5 MHOWS, subjects treated with lofexidine had significantly lower scores (equating to fewer/less severe withdrawal symptoms) than placebo subjects (least squares means 19.5+/-2.1 versus 30.9+/-2.7; p=0.0019). Lofexidine subjects had significantly better retention in treatment than placebo subjects (38.2% versus 15.2%; Log rank test p=0.01). CONCLUSIONS: Lofexidine is well tolerated and more efficacious than placebo for reducing opioid withdrawal symptoms in inpatients undergoing medically supervised opioid detoxification.

Clinical pharmacokinetics of lofexidine, the alpha 2-adrenergic receptor agonist, in opiate addicts plasma using a highly sensitive liquid chromatography tandem mass spectrometric analysis.

OBJECTIVES: The objective of this investigation was to characterize the pharmacokinetic profile of lofexidine. Lofexidine is an orally bioavailable alpha 2-adrenergic receptor agonist analogue of clonidine that acts centrally to suppress opiate withdrawal symptoms. METHODS: During the detoxification period of a phase 3 placebo-controlled, randomized, double-blind trial, six subjects were entered in this preliminary pharmacokinetic study. RESULTS: Pharmacokinetic analysis of plasma samples collected during study day 7 indicated that C(max) was 3242 +/- 917 ng/L. The mean trough levels between the study days were not significantly different (p > .05), suggesting that the subjects were at steady-state. CONCLUSIONS: Although preliminary due to the limited number of subjects, these findings are the first to document lofexidine clinical pharmacokinetics in opiate addicts using a highly sensitive liquid chromatography tandem mass spectrometric analysis.

Biotechnology and the treatment of addictive disorders: new opportunities.

Addiction is a chronic relapsing illness with onset typically occurring in the early teenage years, followed by cycles of drug use and abstinence. The disease is mitigated by complex interactions between genes and environment. Viewed as such, the treatment of addiction could span the whole lifetime of the patient and, ideally, should be tailored to the illness cycle. The search for effective treatments has intensified recently due to our better understanding of the underlying neurobiologic mechanisms contributing to drug use and relapse. The three main types of treatment are behavioral, pharmacologic and, more recently, immunologic therapies. Vaccines and monoclonal antibodies are being developed mainly for stimulant use disorders and nicotine addiction. In addition, new molecular targets identified by preclinical research have shown promise and are awaiting proof-of-concept studies in humans. The main focus of this review is on the development of immunotherapy for stimulants and nicotine addiction as a model highlighting the current status of the science and potential emerging discoveries and development.

The NIDA Methamphetamine Clinical Trials Group: a strategy to increase clinical trials research capacity.

AIMS: In order to increase the number of investigative teams and sites conducting research on pharmacological treatments for methamphetamine use disorders, the National Institute on Drug Abuse (NIDA) established an infrastructure of clinical sites in areas where methamphetamine addiction is prevalent. This multi-site infrastructure would serve to run multiple Phases II and III protocols effectively and expeditiously. METHODS: NIDA collaborated with investigators from the University of California at Los Angeles (UCLA) to set up the Methamphetamine Clinical Trials Group (MCTG). This paper describes the development process, as well as data from a test trial to assess the capability of research-naive sites to recruit research participants and conduct study procedures according to research protocol. Subsequent trials are also described. RESULTS: A total of 151 candidates signed consent; 65 individuals were enrolled and 35 (53.8%) completed the 12 weeks' behavioral trial. Self-reported substance use report (SUR) showed comparable use of methamphetamine across sites with the individual site means ranging from 59% (site 5) to 80% (site 3). Drug use as measured by urinalysis was greatly reduced at week 13 compared to the baseline measure; the average rate of methamphetamine-free urine samples across all participants in sites at week 13 was 53%. The highest percentage of methamphetamine-free samples was 85% at site 5; the lowest was at site 1 (40%). Addiction severity index (ASI) composite scores at baseline and protocol completion for all participants demonstrated improvement in all categories over time, except for the medical composite score. The largest composite score reduction in baseline-protocol completion was in the drug domain (0.23 versus 0.15). The changes in the ASI scores from baseline to week 13 were consistent across all five sites. CONCLUSIONS: Outcomes of the behavioral trial indicated that the MCTG recruited well; collected study data accurately and reliably; and created a vehicle that can assess promising pharmacotherapies for methamphetamine addiction treatment medications. The MCTG strategy appears to be a feasible approach to increase NIDA's capacity to conduct clinical trials to evaluate potential pharmacotherapies for methamphetamine addiction.

A double-blind, placebo-controlled trial of tiagabine for the treatment of cocaine dependence.

BACKGROUND: The potential efficacy of tiagabine for treating cocaine dependence is suggested by both pre-clinical research and two small clinical trials. METHOD: One hundred and forty one participants who met DSM-IV criteria for cocaine dependence were enrolled into this 12-week, double blind, placebo controlled outpatient trial. Participants received either tiagabine (20 mg/day) or matching placebo. All participants received 1h of manualized individual cognitive behavioral therapy on a weekly basis. Outcome measures included cocaine use as determined by self-report confirmed with urine benzoylecgonine (BE) results, and qualitative and quantitative urine toxicology measures. Safety measures included adverse events, EKGs, vital signs, and laboratory tests. RESULTS: Seventy-nine participants (i.e., 56%) completed the 12-week trial. The safety results suggest that tiagabine was safe and generally well tolerated by the participants. Participants in both groups improved significantly on cocaine craving and global functioning, with no significant differences between the groups. There were no significant changes in cocaine use as measured by self-report confirmed by urine BE or by quantitative urine toxicology results. Qualitative urine toxicology results suggest a possible weak effect for tiagabine in reducing cocaine use. CONCLUSION: These results suggest that tiagabine, at a dose of 20 mg/day, did not have a robust effect in decreasing cocaine use.

A double-blind, placebo-controlled trial of reserpine for the treatment of cocaine dependence.

BACKGROUND: Cocaine's increase of dopamine is strongly associated with its reinforcing properties and, thus, agents that reduce dopamine have received much attention as candidate cocaine-dependence treatments. The potential efficacy of reserpine, a dopamine depletor, for treating cocaine dependence is suggested by both pre-clinical research and a small clinical trial. METHOD: One hundred and nineteen participants who met DSM-IV criteria for cocaine dependence were enrolled into this 12-week, double-blind, placebo-controlled outpatient trial. Participants received either reserpine (0.5 mg/day) or matching placebo. All participants received 1h of manualized individual cognitive behavioral therapy on a weekly basis. Outcome measures included cocaine use as determined by self-report confirmed with urine benzoylecgonine results, cocaine craving, addiction severity index scores, and clinical global impression scores. Safety measures included adverse events, EKGs, vital signs, laboratory tests, and the Hamilton Depression Inventory. RESULTS: Seventy-nine participants (i.e., 66%) completed the 12-week trial. The safety results suggest that reserpine was safe and well tolerated by the participants. The efficacy measures indicated no significant differences between reserpine and placebo. CONCLUSION: These results do not support the efficacy of reserpine as a cocaine-dependence treatment.

Prevalence of abnormal liver-associated enzymes in cocaine experienced adults versus healthy volunteers during phase 1 clinical trials.

The frequency and nature of elevation of liver-associated enzymes (LAE) are important safety endpoints in Phase 1 clinical trials of new anti-cocaine agents, yet very little information is available on the prevalence of abnormal LAE in cocaine experienced adults. The aim of this retrospective study was to investigate the alterations of liver-associated enzymes (LAE) aspartate- (AST) and alanine transaminase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), and bilirubin in healthy "normal" (HN) and cocaine experienced (actively using cocaine preadmission (CE)) adults participating in long term inpatient clinical trials. We examined LAE values collected from 3 inpatient Phase 1 trials of anti-cocaine agents. Analysis of variance (ANOVA) was applied to determine the significance of various factors on LAE alterations. Gender, baseline BMI, treatment did not demonstrate significant group differences in LAE levels. CE study volunteers were found to have significantly higher AST and ALT values than HN volunteers (P<0.05) during their respective inpatient stays. 94.1% of the 17 subjects with abnormal LAE were CE, and 37.5% of these CE received placebo. In conclusion, despite normal baseline values, most subjects demonstrated an increase in the ALT level even on placebo. For CE subjects, differences (Delta ALT and Delta AST) between baseline and the maximum observed values were significantly higher than that observed for HN subjects. The potential to obscure important signals for hepatotoxicity during Phase 1 research may be higher in the CE study population.

Bupropion reduces methamphetamine-induced subjective effects and cue-induced craving.

Bupropion is an antidepressant with stimulant properties, which inhibits the reuptake of dopamine (DA) and norepinepherine, and is purported to enhance DA neurotransmission. Bupropion is considered an appealing candidate medication for the treatment of methamphetamine dependence. The current laboratory study was set forth to assess the impact of bupropion treatment on the subjective effects produced by methamphetamine in the laboratory. We also assessed the effects of bupropion treatment on craving elicited by exposure to videotaped methamphetamine cues. A total of 26 participants were enrolled and 20 completed the entire study (n=10 placebo and n=10 bupropion, parallel groups design). Bupropion treatment was associated with reduced ratings of 'any drug effect' (p<0.02), and 'high' (p<0.02) following methamphetamine administration. There was also a significant bupropion-by-cue exposure interaction on General Craving Scale total score (p<0.002), and on the Behavioral Intention subscale (p<0.001). Overall, the data reveal that bupropion reduced acute methamphetamine-induced subjective effects and reduced cue-induced craving. Importantly, these data provide a rationale for the evaluation of bupropion in the treatment of methamphetamine dependence.

Double-blind, placebo-controlled trial of selegiline transdermal system (STS) for the treatment of cocaine dependence.

BACKGROUND: Cocaine dependence is a major public health problem for which there is no FDA-approved pharmacological treatment. Selegiline is an irreversible selective inhibitor of monoamine oxidase type B (MAO-B) which may affect cocaine addiction through several potential mechanisms. In this study, selegiline transdermal system (STS) was compared to placebo as a treatment for cocaine dependence. This multi-site, double-blind trial of 300 subjects with cocaine dependence assessed the efficacy of selegiline using subject self-reported cocaine use substantiated by urine benzoylecgonine (BE) as the primary outcome measure. Analysis of the data did not show a significant effect for selegiline over placebo. This study does not support a role for selegiline in treating cocaine dependence. The contrast of this result to earlier, promising preclinical and human pilot data could be due to factors associated with sample size, patient characteristics, dose, or poor predictive validity of preclinical models.

A preliminary randomized, double-blind, placebo-controlled study of the safety and efficacy of ondansetron in the treatment of cocaine dependence.

Prior studies have demonstrated inefficacy among dopamine receptor antagonists for treating cocaine dependence. An alternative approach would be to investigate the ability of indirect inhibitors of cortico-mesolimbic dopamine release, such as the 5-HT(3) receptor antagonist ondansetron, to reduce cocaine's reinforcing effects. We hypothesized that ondansetron might be more efficacious than placebo at reducing cocaine intake and promoting abstinence in cocaine-dependent individuals. In a pilot randomized, double-blind, 10-week controlled trial, 63 treatment-seeking, cocaine-dependent men and women received ondansetron (0.25 mg, 1.0 mg, or 4.0 mg twice daily) or placebo. Up to three times per week, participants were assessed on several measures of cocaine use, including urine benzoylecgonine. Cognitive behavioral therapy was administered weekly. Ondansetron was well tolerated, causing no serious adverse events. The ondansetron 4.0 mg group had the lowest dropout rate among all treatment groups and a greater rate of improvement in percentage of participants with a cocaine-free week compared with the placebo group (p = 0.02), whereas the ondansetron 1.0 mg group had a lower rate of improvement in percentage of weekly mean non-use days than did placebo recipients (p = 0.04). These results suggest the possibility of a non-linear dose-response function, with evidence supporting efficacy for the 4.0 mg group.

Methylphenidate and cocaine: a placebo-controlled drug interaction study.

Up to thirty percent of cocaine addicted individuals may meet diagnostic criteria for Attention-Deficit/Hyperactivity Disorder (ADHD). Methylphenidate (MPH) is a highly effective and commonly used treatment for ADHD but, like cocaine, is a cardiovascular and central nervous system stimulant with the potential to cause toxicity at high doses. The present study was undertaken to investigate the likelihood of a toxic reaction in individuals who use cocaine while concurrently taking MPH. Seven non-treatment seeking cocaine-dependent individuals completed this placebo-controlled, crossover study with two factors: Medication (placebo, 60 mg MPH, 90 mg MPH) and Infusion (saline, 20 mg cocaine, 40 mg cocaine). Physiological measures included vital signs, adverse events, and electrocardiogram. Subjective response was measured with visual analog scale (VAS) ratings of craving and drug effect. Cocaine pharmacokinetic parameters were calculated for each participant at each drug combination, using a non-compartmental model. MPH was well tolerated, did not have a clinically significant impact on cocaine's physiological effects, and decreased some of the positive subjective effects of cocaine. MPH did not significantly alter the pharmacokinetics of cocaine. The study results suggest that MPH at the doses studied can likely be used safely in an outpatient setting with active cocaine users.