Bupropion sustained release (SR) for the treatment of hypoactive sexual desire disorder (HSDD) in nondepressed women.

This article describes the results of the first report of bupropion sustained release (SR) in nondepressed females with hypoactive sexual desire disorder (HSDD). Eligible females entered a 4-week, single-blind, placebo baseline phase. Subjects, all of whom did not respond to placebo, continued in a single-blind active treatment phase where they received bupropion SR for up to 8 additional weeks. We assessed HSDD by using investigator ratings of sexual desire and sexual functioning. Of the 51 evaluable subjects who entered the active treatment phase, 29% responded to treatment with bupropion SR. Bupropion SR was generally well tolerated. Pending the results of further study, bupropion SR may offer a treatment option for women with HSDD.

Response in relation to baseline anxiety levels in major depressive disorder treated with bupropion sustained release or sertraline.

Our objective was to determine if pretreatment anxiety levels were associated with preferential response to bupropion sustained release (n = 122) or sertraline (n = 126) during a 16-week randomized acute phase treatment study. Both agents had comparable antidepressant activity, and comparable anxiolytic effects using the intent-to-treat sample. Baseline anxiety levels were not related to antidepressant efficacy, and they did not differentiate responders to each agent. Time to clinically significant anxiolysis did not differentiate between treatment groups or between responders to each agent. These results contradict the commonly held, but unsubstantiated, belief that in clinically depressed anxious patients, serotonergic antidepressants are especially anxiolytic and that such patients preferentially benefit from the antidepressant or anxiolytic effects of selective serotonin reuptake inhibitors. Thus, the clinical decision to select between these two agents when treating depressed outpatients cannot rest on either levels of pretreatment anxiety or on anticipation of more rapid or more complete anxiolysis.

Does pretreatment anxiety predict response to either bupropion SR or sertraline?

BACKGROUND: A common clinical belief is that more sedating and/or serotonin-selective antidepressants are preferred for depressed patients with symptoms of anxiety compared with more activating and/or catecholamine-selective antidepressants. The purpose of this study was to determine whether higher baseline anxiety is associated with different antidepressant responses to bupropion sustained release (SR) or sertraline. METHODS: A retrospective data analysis was conducted using pooled data from two identical 8-week, randomized, double-blind, placebo-controlled multicenter studies of bupropion SR (n=234), sertraline (n=225), and placebo (n=233) in adult outpatients with recurrent, major depressive disorder. Anxiety symptoms were measured using the 14-item Hamilton Anxiety Rating Scale scores. RESULTS: Baseline anxiety levels were not related to antidepressant response to treatment with either bupropion SR or sertraline, nor did they differentiate between responders to bupropion SR and responders to sertraline. CONCLUSIONS: Baseline anxiety levels do not appear to be a basis for selecting between bupropion SR and sertraline in the treatment of outpatients with major depressive disorder.

A double-blind, placebo-controlled, prophylaxis study of lamotrigine in rapid-cycling bipolar disorder. Lamictal 614 Study Group.

BACKGROUND: Patients with rapid-cycling bipolar disorder are often treatment refractory. This study examined lamotrigine as maintenance monotherapy for rapid-cycling bipolar disorder. METHOD: Lamotrigine was added to patients' current psychotropic regimens and titrated to clinical effect during an open-label treatment phase. Stabilized patients were tapered off other psychotropics and randomly assigned to lamotrigine or placebo monotherapy for 6 months. Time to additional pharmacotherapy for emerging symptoms was the primary outcome measure. Secondary efficacy measures included survival in study (time to any premature discontinuation), percentage of patients stable without relapse for 6 months, and changes in the Global Assessment Scale and Clinical Global Impressions-Severity scale. Safety was assessed from adverse event, physical examination, and laboratory data. RESULTS: 324 patients with rapid-cycling bipolar disorder (DSM-IV criteria) received open-label lamotrigine, and 182 patients were randomly assigned to the double-blind maintenance phase. The difference between the treatment groups in time to additional pharmacotherapy did not achieve statistical significance in the overall efficacy population. However, survival in study was statistically different between the treatment groups (p = .036). Analyses also indicated a 6-week difference in median survival time favoring lamotrigine. Forty-one percent of lamotrigine patients versus 26% of placebo patients (p = .03) were stable without relapse for 6 months of monotherapy. Lamotrigine was well tolerated; there were no treatment-related changes in laboratory parameters, vital signs, or body weight. No serious rashes occurred. CONCLUSION: This was the largest and only prospective placebo-controlled study of rapid-cycling bipolar disorder patients to date; results indicate lamotrigine monotherapy is a useful treatment for some patients with rapid-cycling bipolar disorder.

Bupropion sustained release versus paroxetine for the treatment of depression in the elderly.

BACKGROUND: Depression is a serious and widespread emotional disorder among the elderly. This study compared the efficacy and safety of bupropion sustained release (SR) with the selective serotonin reuptake inhibitor paroxetine in the treatment of major depression in elderly outpatients. METHOD: Elderly (> or = 60 years) outpatients with major depressive disorder (DSM-IV criteria) were evaluated in this 6-week multicenter, randomized, double-blind study comparing bupropion SR, 100-300 mg/day, and paroxetine, 10-40 mg/day. Efficacy was assessed by changes in scores on the Hamilton Rating Scales for Depression (HAM-D) and Anxiety (HAM-A) and the Clinical Global Impressions-Severity of Illness and -Improvement scales. Safety was assessed by monitoring adverse events, vital signs, and body weight. RESULTS: A total of 100 patients ranging in age from 60 to 88 years were randomly assigned to treatment with bupropion SR (N = 48) or paroxetine (N = 52). Measurements of efficacy were similar between the 2 treatment groups, with both groups showing improved scores on all depression rating scales. Headache, insomnia, dry mouth, agitation, dizziness, and nausea occurred in > 10% of patients in both groups; somnolence, diarrhea, constipation, and anorexia occurred in > 10% of patients in the paroxetine group. No statistically significant differences between groups in vital signs or weight were found. CONCLUSION: Both bupropion SR and paroxetine were safe and effective for the treatment of depression in the elderly. Because of its favorable side effect profile, bupropion SR may provide a safe and effective nonserotonergic treatment alternative that is well suited as an antidepressant for the elderly.

Evaluation of sexual functioning in depressed outpatients: a double-blind comparison of sustained-release bupropion and sertraline treatment.

Sexual dysfunction is a frequently reported side effect of many antidepressants, including serotonin reuptake inhibitors. Bupropion, an antidepressant of the aminoketone class, is relatively free of adverse sexual effects. In a randomized, double-blind, multicenter trial, sustained-release bupropion (bupropion SR) and sertraline, a selective serotonin reuptake inhibitor, were found to be similarly efficacious in the treatment of outpatients with moderate to severe depression. This report describes the results of a double-blind comparison of the sexual side effect profiles of bupropion SR and sertraline. Two hundred forty-eight patients who had received a diagnosis of moderate to severe major depression were randomly assigned to receive treatment with bupropion SR (100-300 mg/day) or sertraline (50-200 mg/day) for 16 weeks. Eligible patients were required to be in a stable relationship and to have normal sexual functioning. Sexual functioning was assessed by the investigator at each clinic visit using investigator-rated structured interviews. A significantly greater percentage of sertraline-treated patients (63% and 41% of men and women, respectively) developed sexual dysfunction compared with bupropion SR-treated patients (15% and 7%, respectively). Sexual dysfunction was noted as early as day 7 in sertraline-treated patients at a dose of 50 mg/day and persisted until the end of the 16-week treatment phase. Four patients, all of whom were treated with sertraline, discontinued from the study prematurely because of sexual dysfunction. Given the similar efficacy of the two drugs in treating depression, bupropion SR may be a more appropriate antidepressant choice than sertraline in patients for whom sexual dysfunction is a concern.

Sexual dysfunction associated with the treatment of depression: a placebo-controlled comparison of bupropion sustained release and sertraline treatment.

This study compared the sexual functioning effects as well as the safety and efficacy of bupropion sustained release (bupropion SR) and sertraline. Three hundred sixty-four patients with normal sexual functioning and recurrent major depression were treated with bupropion SR (150-400 mg/day), sertraline (50-200 mg/day), or placebo for 8 weeks in this randomized, double-blind, multicenter study. Patients' depression, sexual functioning, and overall safety were assessed at regular clinic visits. Significantly (P < 0.05) more patients treated with sertraline experienced orgasm dysfunction compared with patients treated with bupropion SR or placebo. Bupropion SR, but not sertraline, was statistically significantly superior to placebo in improving scores on all depression scales by the end of the study. Headache occurred with similar frequency in all groups. Gastrointestinal disturbances occurred more frequently with sertraline; insomnia and agitation occurred more frequently with bupropion SR. Small decreases in mean weight were seen with both active treatments; the placebo group experienced a minor increase in mean weight. Both bupropion SR and sertraline were generally well tolerated, although sertraline was more often associated with sexual dysfunction. Bupropion SR, but not sertraline, was statistically superior to placebo in relieving depression by the end of the study. Bupropion SR may offer advantages over sertraline in treating depressed patients concerned with sexual functioning.

Spectrum of activity of lamotrigine in treatment-refractory bipolar disorder.

OBJECTIVE: New mood stabilizers are needed that possess efficacy for all phases of bipolar disorder. This study was designed to provide preliminary evidence for the safety and efficacy of a new anticonvulsant, lamotrigine, in adult patients with bipolar disorder who had been inadequately responsive to or intolerant of prior pharmacotherapy. METHOD: A 48-week, open-label, prospective trial was conducted in 75 patients with bipolar I or bipolar II disorder. Lamotrigine was used as adjunctive therapy (N = 60) or monotherapy (N = 15) in patients presenting in depressed, hypomanic, manic, or mixed states. RESULTS: Of the 40 depressed patients included in the efficacy analysis, 48% exhibited a marked response and 20% a moderate response as measured by reductions in 17-item Hamilton Depression Rating Scale scores. Of the 31 with a hypomanic, manic, or mixed state, 81% displayed a marked response and 3% a moderate response on the Mania Rating Scale. From baseline to endpoint, the depressed patients exhibited a 42% decrease in Hamilton depression scale scores, and the patients presenting with hypomania, mania, or a mixed state exhibited a 74% decrease in Mania Rating Scale scores. The most common drug-related adverse events were dizziness, tremor, somnolence, headache, nausea, and rash. Rash was the most common adverse event resulting in drug discontinuation (9% of patients); one patient developed a serious rash and required hospitalization. CONCLUSIONS: These open-label data provide preliminary evidence that lamotrigine may be an effective treatment option for patients with refractory bipolar disorder; however, potential benefits must be weighed against potential side effects, including rash.

A placebo-controlled comparison of the antidepressant efficacy and effects on sexual functioning of sustained-release bupropion and sertraline.

Sexual dysfunction, a frequently reported side effect of many antidepressants, may result in patient dissatisfaction and noncompliance with treatment regimens. This paper describes the results of the first placebo-controlled comparison of the efficacy, safety, and effects on sexual functioning of sustained-release bupropion (bupropion SR) and the selective serotonin reuptake inhibitor sertraline. This randomized, double-masked, double-dummy, parallel-group, multicenter trial enrolled 360 patients with moderate-to-severe recurrent major depression. Patients were treated with bupropion SR 150 to 400 mg/d, sertraline 50 to 200 mg/d, or placebo for up to 8 weeks. Patients' depression and sexual functioning were assessed at weekly or biweekly clinic visits; safety was assessed by regular monitoring of adverse events, vital signs, and body weight. Treatment groups were similar at baseline in terms of age, sex, and race, and most patients had a diagnosis of moderate uncomplicated depression. Patients treated with bupropion SR or sertraline showed similar improvements on all efficacy measures; both active treatments were superior to placebo in improving scores on all rating scales for depression at various time points. Significantly more patients treated with sertraline experienced orgasmic dysfunction throughout the study than did patients treated with bupropion SR or placebo (P < 0.001). Headache was the most frequently reported adverse event in all 3 treatment groups and occurred with similar frequency in each group (30% to 40%). Nausea (31%), diarrhea (26%), insomnia (18%), and somnolence (17%) occurred in significantly more patients in the sertraline group than in the bupropion SR group (18%, 7%, 13%, and 3%, respectively) and the placebo group (10%, 11%, 4%, and 6%, respectively). Dry mouth occurred more frequently with bupropion SR (19%) than with sertraline (14%) or placebo (12%), although the differences were not significant. Changes in vital signs were similar in all groups. Similar (small, but not statistically significant) decreases in mean body weight were seen in both the bupropion SR (-1.06 kg) and sertraline (-0.79 kg) groups, whereas the placebo group experienced a minor increase (0.21 kg). Although bupropion SR and sertraline were similarly well tolerated and effective in the treatment of depression, sertraline treatment was more often associated with sexual dysfunction and certain other adverse events compared with bupropion SR and placebo. Therefore, bupropion SR may be an appropriate choice as an antidepressant for the treatment of sexually active patients.

Safety profile of sustained-release bupropion in depression: results of three clinical trials.

This series of studies was undertaken to assess the safety profile of sustained-release (SR) bupropion in the treatment of depressed outpatients. Adults with a diagnosis of major depression were evaluated in 1 of 3 multicenter, randomized, double-masked, parallel-group, placebo-controlled trials conducted in private-practice psychiatric outpatient clinics. Following a 1-week, single-masked, placebo lead-in period, patients received bupropion SR for 8 weeks (study 1: 150 or 300 mg/d; study 2: 100, 200, 300, or 400 mg/d; study 3: 50 to 150 or 100 to 300 mg/d). Safety assessments included monitoring adverse events, patient discontinuation rates, changes in weight, vital signs, and clinical laboratory test results. Across studies, the most frequently reported adverse events were headache, dry mouth, and nausea. The incidence of adverse events was similar (< or =5% difference) between the bupropion SR and placebo groups, with the exception of dry mouth (bupropion SR, 16%; placebo, 7%). Dry mouth, nausea, and insomnia occurred significantly more often in bupropion SR-treated patients than in patients who received placebo (P<0.05). Nearly all (94% to 99%) adverse events reported in these studies were mild or moderate. Less than 10% of patients in either group discontinued treatment prematurely because of adverse events, and no deaths or serious drug-related adverse events were reported. Sexual dysfunction was reported as an adverse event by <1% of patients in either group. Bupropion SR was associated with dose-related weight loss in all 3 studies. No consistent patterns of change were observed in vital signs or in the results of clinical laboratory tests. Data from these 3 clinical trials demonstrate the favorable safety profile of bupropion SR in the treatment of depressed outpatients.

A double-blind placebo-controlled study of lamotrigine monotherapy in outpatients with bipolar I depression. Lamictal 602 Study Group.

BACKGROUND: More treatment options for bipolar depression are needed. Currently available antidepressants may increase the risk of mania and rapid cycling, and mood stabilizers appear to be less effective in treating depression than mania. Preliminary data suggest that lamotrigine, an established antiepileptic drug, may be effective for both the depression and mania associated with bipolar disorder. This is the first controlled multicenter study evaluating lamotrigine monotherapy in the treatment of bipolar I depression. METHODS: Outpatients with bipolar I disorder experiencing a major depressive episode (DSM-IV, N = 195) received lamotrigine (50 or 200 mg/day) or placebo as monotherapy for 7 weeks. Psychiatric evaluations, including the Hamilton Rating Scale for Depression (HAM-D), the Montgomery-Asberg Depression Rating Scale (MADRS), Mania Rating Scale, and the Clinical Global Impressions scale for Severity (CGI-S) and Improvement (CGI-I) were completed at each weekly visit. RESULTS: Lamotrigine 200 mg/day demonstrated significant antidepressant efficacy on the 17-item HAM-D, HAM-D Item 1, MADRS, CGI-S, and CGI-I compared with placebo. Improvements were seen as early as week 3. Lamotrigine 50 mg/day also demonstrated efficacy compared with placebo on several measures. The proportions of patients exhibiting a response on CGI-I were 51%, 41%, and 26% for lamotrigine 200 mg/day, lamotrigine 50 mg/day, and placebo groups, respectively. Adverse events and other safety results were similar across treatment groups, except for a higher rate of headache in the lamotrigine groups. CONCLUSION: Lamotrigine monotherapy is an effective and well-tolerated treatment for bipolar depression.

A prospective safety surveillance study for bupropion sustained-release in the treatment of depression.

BACKGROUND: This prospective 105-site study was conducted to determine the rate of seizures and other serious adverse experiences associated with the therapeutic use of the sustained-release formulation of bupropion (bupropion SR). METHOD: 3100 patients with a DSM-III-R diagnosis of depression without a current or past diagnosis of an eating disorder and with no personal or family history of seizure disorders were treated for up to 8 weeks with bupropion SR in an open-label study. Dosing was initiated at 50 mg b.i.d. and increased to a maximum of 150 mg b.i.d. unless not tolerated. Patients had the option to continue treatment with bupropion SR (50 mg b.i.d. to 150 mg b.i.d.) in a continuation phase lasting up to 1 year. During the acute and continuation phases, patients were evaluated for the occurrence of seizures and other serious adverse experiences. Clinical response to and tolerability of bupropion SR were also evaluated. RESULTS: Three patients each experienced a seizure associated with the therapeutic use of bupropion SR during the acute and continuation phases combined. The observed seizure rate during the 8-week acute phase was 2 seizures in 3094 evaluable patients, or 0.06%. The observed seizure rate for the acute and continuation phases combined was 3 seizures in 3094 patients, or 0.10%. Survival analysis yielded a cumulative seizure rate of 0.08% for the acute phase and 0.15% for both phases combined. Two patients who intentionally overdosed with bupropion SR also experienced seizures; however, these events were not included in calculations of the overall seizure rate. Therapeutic doses of bupropion SR were well tolerated and clinically efficacious. CONCLUSION: The therapeutic use of bupropion SR at total daily doses up to 300 mg/day in depressed patients without predisposition to seizures is associated with a seizure rate that is well within the range observed with other marketed antidepressants.

A multicenter evaluation of the efficacy and safety of 150 and 300 mg/d sustained-release bupropion tablets versus placebo in depressed outpatients.

This multicenter, randomized, double-masked, placebo-controlled, parallel-group study compared the antidepressant efficacy and safety of bupropion sustained-release (SR) tablets (150 mg QD or 150 mg BID) with placebo in outpatients with moderate-to-severe depression. The study consisted of a 1-week placebo phase followed by 8 weeks of active treatment with bupropion SR 150 mg/d (150 mg QD, n = 121) or 300 mg/d (150 mg BID, n = 120) or placebo (n = 121). Efficacy was measured by changes in scores on the 17-item Hamilton Rating Scale for Depression (HAM-D) and the Clinical Global Impressions for Severity of Illness (CGI-S) and Clinical Global Impressions for Improvement of Illness (CGI-I) scales. Safety was monitored by regular assessment of vital signs and adverse events as well as by pretreatment and posttreatment physical and clinical laboratory examinations. By day 56, both bupropion SR treatments were more effective in relieving the symptoms of depression than was placebo. Compared with those receiving placebo, patients in the bupropion SR 150- and 300-mg/d groups had significantly reduced symptoms by treatment day 56, as measured on the 17-item HAM-D, CGI-S, and CGI-I scales (P < 0.05). Bupropion SR was well tolerated, with no serious adverse events reported by bupropion-treated patients; 95% of all reported adverse events were of mild or moderate intensity. No clinically significant changes in vital signs, laboratory test results, or physical findings were observed. A greater mean weight loss was observed at the end of treatment in both the bupropion SR 150-mg (0.5 kg) and bupropion SR 300-mg (1.0 kg) group compared with placebo (0.2 kg). We found that bupropion SR 150 mg administered either once or twice daily was more effective than placebo in treating depression and that once-daily dosing appears to be at least as effective as twice-daily dosing. Should this prove true, depressed patients may be able to benefit from the convenience and improved tolerability associated with once-daily dosing.

Pharmacokinetics of bupropion and its metabolites in cigarette smokers versus nonsmokers.

Bupropion is an antidepressant agent that is also effective as an aid to quit cigarette smoking. A single 150-mg tablet of sustained-release bupropion hydrochloride was administered to two groups of volunteers, cigarette smokers and nonsmokers, who were matched for race, gender, body frame, age, and weight. Pharmacokinetic parameters were calculated for bupropion, and three major metabolites (hydroxybupropion and the aminoalcohol isomers, threohydrobupropion and erythrohydrobupropion, expressed as a composite total). Mean (+/-SD) values of area under the concentration-time curve from time 0 extrapolated to infinity (AUC0-infinity), maximum concentration (Cmax), time to reach Cmax (tmax), and half-life (t1/2) of bupropion in smokers and nonsmokers, respectively, were 1,164 +/- 220 ng.hr/mL and 1,161 +/- 292 ng.hr/mL; 144 +/- 28 ng/mL and 143 +/- 39 ng/mL; 3.00 +/- 0.50 hours and 2.88 +/- 0.49 hours; and 19 +/- 5 hours and 18 +/- 3 hours. No clinically significant differences between smokers and nonsmokers or between male and female volunteers were observed for the pharmacokinetics of bupropion or its metabolites. The absence of pharmacokinetic differences indicates that dosage adjustments are not necessary when bupropion is prescribed to male and female cigarette smokers.

Double-blind comparison of bupropion sustained release and sertraline in depressed outpatients.

BACKGROUND: A sustained-release formulation of bupropion (bupropion SR), developed with an improved pharmacokinetic profile to permit less frequent dosing than the immediate-release form, has not been evaluated in active comparator trials. This randomized, double-blind, parallel-group trial was conducted to compare the efficacy and safety of bupropion SR and sertraline. METHOD: Outpatients with moderate to severe major depressive disorder (DSM-IV) received bupropion SR (100-300 mg/day) or sertraline (50-200 mg/day) for 16 weeks. Psychiatric evaluations, including the Hamilton Rating Scale for Depression (HAM-D), the Hamilton Rating Scale for Anxiety (HAM-A), the Clinical Global Impressions scale for Severity of Illness (CGI-S), and for Improvement (CGI-I) were completed, and adverse events were assessed in the clinic periodically throughout treatment. Patients' orgasm function was also assessed. RESULTS: Mean HAM-D, HAM-A, CGI-I, and CGI-S scores improved over the course of treatment in both the bupropion SR group and the sertraline group; no between-group differences were observed on any of the scales. Orgasm dysfunction was significantly (p < .001) more common in sertraline-treated patients compared with bupropion SR-treated patients. The adverse events of nausea, diarrhea, somnolence, and sweating were also experienced more frequently (p < .05) in sertraline-treated patients. No differences were noted between the two treatments for vital signs and weight. CONCLUSION: This double-blind comparison of bupropion SR and sertraline demonstrates that bupropion and sertraline are similarly effective for the treatment of depression. Both compounds were relatively well tolerated, and orgasm dysfunction, nausea, diarrhea, somnolence, and sweating were reported more frequently in sertraline-treated patients.

Efficacy and safety of divided dose administration of mivacurium for a 90-second tracheal intubation.

STUDY OBJECTIVE: To compare the safety and effectiveness of 0.25 mg divided doses of mivacurium chloride to succinylcholine for a 90-second tracheal intubation. DESIGN: Randomized, double-blind, multicenter study in two groups. SETTING: Operating rooms at four university medical centers. PATIENTS: 200 healthy ASA status I and II adult patients scheduled for elective surgery with general anesthesia and endotracheal intubation. INTERVENTIONS: Patients were premedicated with 1 to 2 mg midazolam and 2 micrograms/kg fentanyl. Anesthesia was induced with 2 mg/kg propofol. Group A received 0.25 mg/kg mivacurium given as a divided dose (0.15 mg/kg followed in 30 seconds with 0.1 mg/kg). Group B (control) received 1.5 mg/kg succinylcholine (SCh) preceded two minutes earlier by 50 micrograms/kg d-tubocurarine (dtc). MEASUREMENTS AND MAIN RESULTS: Tracheal intubation grading, train-of-four response of the adductor pollicis, heart rate (HR), and mean arterial blood pressure (MAP) were measured and evaluated. Chi-square analysis was performed for comparison between Group A and Group B with respect to the frequency distribution of intubation using the scores excellent, good, and poor and not possible (combined). Group B had a significantly higher excellent score of intubation than Group A, 84% versus 56% (p < 0.0001). No significant difference was found between the two groups when the scores excellent and good were combined (Fisher's Exact test, p = 0.28). The changes in MAP and HR were similar for the two groups. CONCLUSIONS: When Sch is not desirable, mivacurium 0.25 mg/kg given as a divided dose provides good to excellent intubation conditions 90 seconds after the initial dose without significant changes in MAP or HR. It can be an appropriate alternative for short surgical procedures. It must be emphasized that this conclusion does not apply to rapid-sequence induction-intubation.

A multicenter trial of bupropion for cocaine dependence in methadone-maintained patients.

We conducted a multi-site, placebo-controlled, randomized double-blind clinical trial comparing bupropion HCL (300 mg/day) to placebo for the treatment of cocaine dependence in methadone-maintained subjects. A total of 149 subjects at three sites participated in a 12-week study. Outcome measures included cocaine use, level of depression, and psychosocial functioning. Results showed no significant differences between placebo and bupropion. Exploratory analyses suggested a medication effect for the subset of subjects depressed at study entry. The need to target subgroups of cocaine abusers in future pharmacotherapy trials and the possible role of treatment readiness are discussed.

Bupropion: a review of its mechanism of antidepressant activity.

BACKGROUND: The mechanism of action of the novel antidepressant bupropion remains unclear after many years of study. A review of the relevant biochemical, in vivo brain microdialysis, electrophysiologic, behavioral, and clinical data clarifies what is known about this unique compound and suggests possible modes of action. METHOD: A panel of 11 experts was convened for a conference to discuss bupropion's mechanism of antidepressant activity. Four of the panelists presented current research findings, followed by a discussion. RESULTS: (1) Biochemical studies suggest down-regulation of postsynaptic beta-adrenoceptors and desensitization of the norepinephrine-stimulated adenylate cyclase in the rat cortex occur only after chronic administration of very high doses of bupropion. (2) In vivo brain microdialysis studies demonstrate that, after chronic administration, there is an enhancement of bupropion-induced increases in extracellular dopamine in the nucleus accumbens. (3) Electrophysiologic data show that with acute dosing, bupropion reduces the firing rates of noradrenergic neurons in the locus ceruleus. The firing rates of dopaminergic neurons are reduced by bupropion in the A9 and A10 areas of the brain, but only at very high doses, and bupropion does not alter the firing rates of serotonergic neurons in the dorsal raphe. (4) Behavioral studies show that the most active metabolite of bupropion, hydroxybupropion (306U73), appears to be responsible for a large part of the compound's effects in animal models of antidepressant activity. (5) Clinical studies indicate that bupropion enhances noradrenergic functional activity as reflected by an increased excretion of the hydroxy metabolite of melatonin, while at the same time producing a presumably compensatory decrease in norepinephrine turnover. In one study, bupropion elevated plasma levels of the dopamine metabolite homovanillic acid in nonresponders, but not in responders. CONCLUSION: The mechanism of action of bupropion appears to have an unusual, not fully understood, noradrenergic link. The bupropion metabolite hydroxybupropion probably plays a critical role in bupropion's antidepressant activity, which appears to be predominantly associated with long-term noradrenergic effects. The mild central nervous system activating effects of bupropion appear to be due to weak dopaminergic mechanisms. There is some evidence that dopamine may contribute to bupropion's antidepressant properties. Antidepressant effects of bupropion are not serotonergically mediated.

Preclinical and early clinical studies with BW 1370U87, a reversible competitive monoamine oxidase-A inhibitor.

BW 1370U87 is unique among potent inhibitors of monoamine oxidase-A (MAO-A) in that it contains no nitrogen. Like other MAO-A inhibitors, BW 1370U87 elevates neurotransmitter amines in the brain over the same dose range at which it exhibits positive activities in animal models of depressive illness. However, BW 1370U87 differs from most other MAO inhibitors in that its mechanism of action follows simple competitive kinetics, so that an unusually high concentration of tyramine in peripheral tissues may displace the inhibitor from MAO-A sites in the intestine and liver. In addition, BW 1370U87 concentrations in brains of rats appear much higher than in plasma, whereas extensive metabolism of the parent compound in the liver produces weaker MAO-A inhibitors with the same type of competitive mechanism. Early phase-I safety trials at acute doses up to 2,000 mg of BW 1370U87 showed no adverse reactions, whereas MHPG in urine was decreased, indicating that in vivo inhibition of MAO-A was achieved in humans. Thus BW 1370U87 represents a new agent with potential therapeutic application in depression and other CNS illnesses.