Onset and early behavioral effects of pharmacologically different antidepressants and placebo in depression

This study was aimed at resolving the time course of clinical action of antidepressants (ADs) and the type of early behavioral changes that precede recovery in treatment-responsive depressed patients. The first goal was to identify, during the first 2 weeks of treatment, the onset of clinical actions of the selective serotonin reuptake inhibitor (SSRI), paroxetine, and the selective noradrenergic reuptake inhibitor, desipramine (DMI). The second aim was to test the hypothesis that the two pharmacologic subtypes would induce different early behavioral changes in treatment-responsive patients. The design was a randomized, parallel group, placebo-controlled, double-blind study for 6 weeks of treatment following a 1-week washout period. The study utilized measures of the major behavioral components of the depressive disorder as well as overall severity. The results indicated that the onset of clinical actions of DMI ranged from 3 to 13 days, averaged 13 days for paroxetine, and was 16-42 days for placebo. Furthermore, as hypothesized, the different types of ADs initially impacted different behavioral aspects of the disorder. After 1 week of treatment, DMI produced greater reductions in motor retardation and depressed mood than did paroxetine and placebo, and this difference persisted at the second week of treatment. Early improvement in depressed mood-motor retardation differentiated patients who responded to DMI after 6 weeks of treatment from those that did not. Paroxetine initially reduced anxiety more in responders than in nonresponders, and by the second week, significantly improved depressed mood and distressed expression in responders to a greater extent. Depressed patients who responded to placebo showed no consistent early pattern of behavior improvement. Early drug-specific behavioral changes were highly predictive of ultimate clinical response to the different ADs, results that could eventually be applied directly to clinical practice.

Combining norepinephrine and serotonin reuptake inhibition mechanisms for treatment of depression: a double-blind, randomized study

BACKGROUND

Although several antidepressants are now available, all have limited efficacy and a delayed onset of action. The current study was undertaken as a proof of the concept that combining norepinephrine and serotonin reuptake inhibition would be more effective and act more rapidly than either drug alone.

METHODS

Inpatients with nonpsychotic unipolar major depression and a Hamilton Depression Rating Scale (HAMD) score of at least 18 after 1 week of hospitalization without antidepressant medication were randomized to 6 weeks of treatment with fluoxetine (FLX) 20 mg/day, desipramine (DMI) adjusted to an adequate plasma level, or the combination of FLX 20 mg/day and DMI, given under double-blind conditions. Twenty-four-hour DMI levels were used to rapidly adjust DMI dose to achieve a therapeutic level and to anticipate the enzyme-inhibiting effects of FLX. Treatment-resistant patients were stratified. Patients were rated with the HAMD and the Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

Thirty-nine patients began treatment. One patient withdrew consent. The DMI-FLX combination was significantly more likely to result in remission on the MADRS than either FLX or DMI alone [53.8% vs. 7.1% and 0%, respectively; chi(2)(2) = 13.49, p =.001]. The advantage for combined treatment was not explained by history of treatment resistance or by drug plasma concentrations. Rapid response, at 1 or 2 weeks, was neither statistically nor meaningfully greater with combined treatment.

CONCLUSIONS

This study supports the hypothesis that the combination of a noradrenergic and serotonergic agent is more likely to result in remission than either selective agent alone during a 6-week treatment period.

Ethnic differences in substance abuse treatment retention, compliance, and outcome from two clinical trials

OBJECTIVE

This study examined the results of two previous studies that evaluated African Americans and whites who were undergoing treatment for cocaine dependence to determine whether the groups differed in pretreatment characteristics, treatment retention, compliance, and cocaine use outcome.

METHODS

Data were taken from two trials (N=111 in each), in which patients were randomly assigned to groups that used different behavioral treatments (cognitive-behavioral treatment and 12-step facilitation) and pharmacotherapies (desipramine and disulfiram).

RESULTS

Few differences between African Americans and whites were found in terms of demographic characteristics, reasons for seeking treatment, or expectations of treatment. In both studies African Americans and whites did not differ significantly with respect to cocaine use outcomes, but African-American participants completed significantly fewer days of treatment than white participants. In study 2, which was not placebo controlled, African Americans who received disulfiram remained in treatment significantly longer than African Americans who did not receive disulfiram. However, in study 1, in which patients took either desipramine or a placebo, no interactions of ethnicity by medication were found. Among patients who expected improvement to take a month or longer in study 1, African Americans remained in treatment for fewer days than whites.

CONCLUSIONS

The behavioral therapies evaluated did not significantly differ in effectiveness for African Americans and whites, suggesting that they are broadly applicable across these ethnic groups. Findings also suggest possible strategies for improving retention of African Americans in treatment. Such strategies might include offering treatment with a medication component and better addressing participants' treatment expectations.

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.

Advances in the management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a commonly encountered condition seen in multiple medical specialties. Recent research has brought dramatic advances in our understanding of the epidemiology, burden of illness, diagnosis, and management of IBS. It is now widely accepted that the prevalence of IBS is between 10% and 20% of the US population and that the direct and indirect costs associated with IBS are significant. The processes required for diagnosis of IBS remain controversial. Scant evidence exists to support exhaustive diagnostic evaluations, and IBS is no longer considered a diagnosis of exclusion. The use of standardized symptom-based criteria remains to be perfected, and the diagnosis is often arrived at only after multiple laboratory, endoscopic, and radiologic examinations. The effects of treatment for IBS mirror the heterogeneous nature of the condition. No single medication has proven to be universally effective, and multiple therapeutic approaches exist. Greater understanding of gastrointestinal neurophysiology has led to promising advances in medical and nonmedical approaches to IBS.

Clinical and sociodemographic predictors of response to augmentation, or dose increase among depressed outpatients resistant to fluoxetine 20 mg/day

OBJECTIVE

Patients with major depressive disorder often show only partial or no response to antidepressants, necessitating next-step interventions such as dose increase or augmentation. Factors moderating response to these next-step interventions are not well-studied.

METHOD

In this randomized, double-blind investigation of next-step treatments in 101 outpatients who failed to respond to fluoxetine 20 mg for 8 weeks, the impact of depressive course and sociodemographic factors on likelihood of treatment response following dose increase or lithium or desipramine augmentation was examined.

RESULTS

After controlling for depression severity at baseline, current marriage and earlier onset of depression were associated with greater likelihood of response in a logistic regression. Intervention strategy was not predictive of response.

CONCLUSION

Marital status and earlier onset of depression may be clinically useful in predicting outcome following any next-step intervention for treatment resistance, rather than with particular strategies.

Prediction of Treatment Outcome by Baseline Urine Cocaine Results and Self‐Reported Cocaine Use for Cocaine and Opioid Dependence

This study examined the usefulness of baseline cocaine urine toxicology results and self-reported days of cocaine use in predicting treatment response in cocaine- and opioid-dependent subjects. Ninety-nine male and 52 female subjects, maintained on buprenorphine, participated in a 24-week, randomized, double-blind, four-cell trial that evaluated desipramine (150 mg/d) or placebo plus contingency management or a noncontingent voucher control. Out of 151, 102 (67%) subjects had cocaine-positive and 49 (32%) cocaine-negative urines at the beginning of treatment. For the previous 30 days before study participation, 91 (60%) subjects reported using cocaine 15 or less days (low baseline cocaine use) and 60 (40%) subjects reported more than 15 days (high baseline cocaine use). By using the treatment effectiveness score (TES) as the outcome measure, a negative urine for cocaine at baseline predicted a better outcome during a 24-week trial for cocaine and opioid use. There also was a significant interaction between baseline cocaine urine results and desipramine response with the urine cocaine-negative group showing greater desipramine response than placebo for opioid and cocaine use. Self-reported cocaine use at baseline did not show significant predictive power for TES scores during the clinical trial. These results suggest that baseline cocaine urine results should be considered as stratifying variables in clinical trials for cocaine dependence.

Effects of methylphenidate, desipramine, and l-dopa on attention and inhibition in children with Attention Deficit Hyperactivity Disorder

The objective of this study was to investigate the effects of methylphenidate (MPH) on attention and inhibition in children with Attention Deficit Hyperactivity Disorder (ADHD) and to establish what the relative contributions of the noradrenergic and dopaminergic systems to this effect were. In addition to MPH, two other drugs were administered in order to affect both transmitter systems more selectively, L-dopa (dopamine (DA) agonist) and desipramine (DMI) (noradrenaline (NA) re-uptake inhibitor). Sixteen children with ADHD performed a stop-task, a laboratory task that measures the ability to inhibit an ongoing action, in a double-blind randomized within-subjects design. Each child received an acute clinical dose of MPH, DMI, L-dopa, and placebo; measures of performance and plasma were determined. The results indicated that inhibition performance was improved under DMI but not under MPH or L-dopa. The response-time to the stop-signal was marginally shortened after intake of DMI. MPH decreased omission and choice-errors and caused faster reaction times to the trials without the stop-tone. No effects of L-dopa whatsoever were noted. Prolactin levels were increased and 5-HIAA levels were lowered under DMI relative to placebo. It is suggested that the effects of MPH on attention are due to a combination of noradrenergic and dopaminergic mechanisms. The improved inhibition under DMI could be serotonergically mediated.

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.

Regional brain metabolic correlates of alpha-methylparatyrosine-induced depressive symptoms: implications for the neural circuitry of depression

CONTEXT

We previously used positron emission tomography (PET) measurement of brain metabolism with 18fluorodeoxyglucose to show that patients receiving selective serotonin reuptake inhibitors (SSRIs) who have a tryptophan depletion-induced return of depressive symptoms have an acute decrease in metabolism in orbitofrontal cortex, dorsolateral prefrontal cortex, and thalamus. Many patients with depression in remission while taking norepinephrine reuptake inhibitors (NRIs) (but not SSRIs) experience a return of depressive symptoms with depletion of norepinephrine and dopamine using alpha-methylparatyrosine (AMPT).

OBJECTIVE

To assess brain metabolic correlates of AMPT administration in patients with depression in remission while receiving NRIs.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, controlled, double-blind trial in which 18 patients recruited in 1997-2000 from the general community who had depression in remission while taking NRIs had PET imaging in a psychiatric research unit following AMPT and placebo administration.

INTERVENTIONS

After initial medication with desipramine and follow-up until response, patients underwent active AMPT (five 1-g doses administered orally over 28 hours) and placebo (diphenhydramine hydrochloride, five 50- mg doses administered similarly) catecholamine depletion challenges in randomized order of assignment, after which PET imaging was performed on day 3 of each condition. Both study conditions were performed 1 week apart.

MAIN OUTCOME MEASURES

Regional brain metabolism rates in patients with and without AMPT-induced return of depressive symptoms.

RESULTS

AMPT-induced return of depressive symptoms was experienced by 11 of the 18 patients and led to decreased brain metabolism in a number of cortical areas, with the greatest magnitude of effects in orbitofrontal (P =.002) and dorsolateral prefrontal (P =.03) cortex and thalamus (P =.006). Increased resting metabolism in prefrontal and limbic areas predicted vulnerability to return of depressive symptoms.

CONCLUSIONS

Different neurochemical systems that mediate depression may have effects on a common brain circuitry. Baseline metabolism in successfully treated depressed patients may predict vulnerability to future episodes of depression.

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.

Regulation of GAP-43 expression by chronic desipramine treatment in rat cultured hippocampal cells

BACKGROUND

The importance of molecular and cellular changes in hippocampus in major depression and in the mechanism of action of antidepressants has become increasingly clear. Identification of novel targets for antidepressants in hippocampus is important to understanding their therapeutic effects.

METHODS

We used cDNA microarray to measure the expression patterns of multiple genes in primary cultured rat hippocampal cells. In situ hybridization and Northern and immunoblotting analysis were used to determine brain regional distribution and mRNA and protein levels of target genes.

RESULTS

After comparing hybridized signals between control and desipramine treated groups, we found that chronic treatment with desipramine increased the expression of six genes and decreased the expression of two genes. One of the upregulated genes is growth associated protein GAP-43. In situ hybridization revealed that desipramine increased GAP-43 gene expression in dentate gyrus but not other brain regions. Northern and immunoblotting analysis revealed that desipramine increased GAP-43 mRNA and protein levels. GAP-43 expression is also increased by another antidepressant, tranylcypromine, but not by lithium or haloperidol.

CONCLUSIONS

Because GAP-43 regulates growth of axons and modulates the formation of new connections, our findings suggest that desipramine may have an effect on neuronal plasticity in the central nervous system.

Comparison of desipramine or carbamazepine to placebo for crack cocaine-dependent patients

The authors compared the effects of desipramine or carbamazepine to placebo in an intensive outpatient program for cocaine abuse. Subjects recruited from an urban drug treatment program were randomly assigned to a double-blind, placebo-controlled, eight-week trial of desipramine, carbamazepine, or placebo. Patient ratings, urine drug screens, and blood samples were obtained weekly. Using survival analysis, the three groups did not differ in time to drop out of treatment. While subjects improved over time on all self-ratings related to cocaine use, mood, and craving, only two items related to mood were significantly different over time as a function of treatment group. Subjects in the two treated groups reported significantly more improvement on self-ratings of depression and irritability. No treatment differences were noted for sustained abstinence or for proportion of positive urine drug screens. Desipramine subjects who attained a minimum blood level were retained in treatment significantly longer than placebo or other non-compliant treatment groups. This finding supports previous reports of a possible role for desipramine in cocaine abuse treatment.

Impact of criteria-based diagnosis of burning mouth syndrome on treatment outcome

AIMS

Burning mouth syndrome (BMS) primarily affects postmenopausal women and is often difficult to treat successfully. Treatment outcomes have been problematic because of failure to distinguish between patients with BMS and patients presenting with oral burning (OB) resulting from other clinical abnormalities. The purpose of this study was to determine characteristics that might uniquely identify BMS patients from patients with OB and to determine whether proper classification influences treatment outcome.

METHODS

The clinical sample consisted of 69 patients (83% female) with an average age of 62 years, pain duration of 2.45 years, and visual analog scale pain rating of 49 mm (rated from 0 to 100 mm). All patients underwent a clinical exam and completed the Multidimensional Pain Inventory and Symptom Checklist 90-Revised.

RESULTS

There were no differences between the BMS and OB groups with respect to age, pain duration, pain intensity, life interference, and levels of psychologic distress. Patients with OB demonstrated more clinical abnormalities than BMS patients. Hyposalivation and greater use of prescription medications, most notably hormone replacement therapy, were more common in the OB group compared with the BMS group. When treatment was provided that corrected an identifiable abnormality, significantly more OB than BMS patients reported greater than 50% relief from baseline pain rating.

CONCLUSION

These data indicate that while BMS and OB groups may initially present with similar clinical and psychosocial features, they are distinguishable with careful diagnosis that often enables successful management of symptoms for each group.

Side effects of desipramine and age

INTRODUCTION

The treatment response of children and adolescents to tricyclic antidepressants differs from that of adults. Few data exist on the impact of age on side effects. This study compares desipramine-associated side effects in children, adolescents, and adults.

METHODS

Data from three trials of desipramine were combined to produce a sample of 148 subjects, aged 7 to 66 years. Pulse and blood pressure were measured at baseline and while participants were receiving desipramine. Side effects were rated by a clinician. For data analysis, subjects were divided into two groups, younger patients (18 and younger) and older patients (19 and older). Group means of side effect ratings and vital signs were compared. Results were also analyzed covarying for plasma levels of desipramine.

RESULTS

There were significant differences between younger and older patients in pulse and blood pressure at baseline, on desipramine, and in changes in vital signs between baseline and medicated states. Younger patients had significantly lower mean ratings for constipation and dry mouth.

DISCUSSION

Treatment with desipramine results in differing degrees of subjective side effects and changes in vital signs across the life cycle. Physicians should not assume that side effects experienced by children and adolescents are identical to those experienced by adults.

Baseline prolactin and L-tryptophan availability predict response to antidepressant treatment in major depression

RATIONALE

Depression may be associated with a hypofunction of central serotonin (5HT) systems. The prolactin response to fenfluramine (PRF) is an indicator of 5HT activity. It has been suggested that the PRF may predict response to different forms of treatment. Baseline cortisol, prolactin, and L-tryptophan ( L-TRP) availability may affect PRF and may also influence response to treatment.

METHOD

In this study, 46 males and 58 females with a DSM-III-R diagnosis of major depression underwent a detailed clinical evaluation and prior to treatment had baseline measures of prolactin, cortisol, L-TRP, and other large neutral amino acids (LNAAs) taken and underwent a fenfluramine challenge. The subjects with major depression entered a 6-week double-blind treatment trial comparing clomipramine and desipramine.

RESULTS

There was no effect on the 6-week outcome of treatment (clomipramine versus desipramine), PRF or baseline cortisol and no interactions between these factors. However, there was a significant effect of baseline prolactin (BLP) and a significant interaction between TRP/LNAA ratio and BLP. Post-hoc analysis revealed that at low TRP/LNAA values, outcome improved as prolactin levels increased while at high TRP/LNAA values the opposite was the case.

CONCLUSION

The PRF did not predict 6-week outcome. BLP and TRP/LNAA ratio measurement is easy and may be useful clinically. We hypothesise that failure to upregulate post-synaptic 5HT receptors in response to low 5HT availability predicts a poor response to antidepressant treatment.

The relationship between homework compliance and treatment outcomes among older adult outpatients with mild-to-moderate depression

OBJECTIVE

The authors extend previous research on homework in psychotherapy by examining the relationship between homework compliance and therapeutic outcome among depressed older adult outpatients (N = 63), addressing previous limitations by using session-by-session therapist ratings of homework compliance and including both interviewer ratings and patient self-reports of outcomes.

METHODS

Patients were participants in a randomized clinical trial evaluating the efficacy of desipramine versus cognitive/behavioral therapy-alone (C/B-Alone) versus a combination of the two (Combined). Given the current study's focus on homework compliance, only patients assigned to conditions with assigned homework in the clinical trial (i.e., C/B-Alone and Combined conditions) were included.

RESULTS

Results of hierarchical regression analyses indicated that homework compliance contributed significantly to posttreatment outcome as measured by both interviewer-administered and patient self-report measures of depression. A separate series of ANOVAs also found significant differences in pre-posttreatment change between patients scoring above and below the median of reported homework compliance. Findings were similar for patients in the C/B-Alone and Combined conditions.

CONCLUSION

The study's results call for additional research on issues related to homework compliance with older adult patients.

In the rat forced swimming test, chronic but not subacute administration of dual 5-HT/NA antidepressant treatments may produce greater effects than selective drugs

The rat forced swimming test (FST) distinguishes selective serotonin (5-HT) and selective noradrenaline (NA) reuptake-inhibitors, which respectively increase swimming and climbing behaviours. However, NA-system-mediated inhibition of 5-HT-induced swimming prevents dual 5-HT/NA reuptake-inhibition to produce concurrently climbing with swimming. Since adaptative neurochemical processes occur in the treatment of depression, we examined the influence of long-term antidepressant treatment on these interactions.

METHODS

(1) Selective [fluoxetine: 10 mg/kg; desipramine: 10 mg/kg] and non-selective [milnacipran: 40 mg/kg; mirtazapine: 20 mg/kg] antidepressants were administered subacutely (3inj) and chronically (17inj) over 16 days. (2) A subacute fluoxetine-desipramine combination (10-10 mg/kg) was administered in rats that were pre-treated with chronic-desipramine (10 mg/kg per day, 14 days). (3) NA-system-mediated interactions were further examined by combining the alpha(2)-receptor agonist clonidine (5, 10, 20, 200 microg/kg) with 10 mg/kg fluoxetine.

RESULTS

(1) Long-term treatment with either fluoxetine or desipramine does not modify the behavioural response produced by their subacute administration. (2) In contrast, whereas subacute-milnacipran increases climbing solely, chronic-milnacipran produces greater anti-immobility effects and increases both climbing and swimming behaviours. Similarly, the fluoxetine-desipramine combination produces climbing solely, but increases both climbing and swimming behaviours in animals pre-treated with chronic-desipramine. Chronic but not subacute-mirtazapine increases swimming behaviour. (3) clonidine dose-dependently antagonizes fluoxetine-induced anti-immobility effects and swimming behaviour.

CONCLUSIONS

Chronic enhancement of NA-transmission alters NA-system-mediated inhibition of 5-HT-induced behaviour in the FST, which may involve alpha(2)-receptors.

Inhibition of norepinephrine uptake in patients with major depression treated with paroxetine

OBJECTIVE

The study examined whether paroxetine inhibits the human norepinephrine transporter in addition to the human serotonin (5-HT) transporter in patients with major depressive disorder.

METHOD

In an open-label, parallel-group, forced-titration study, 52 outpatients with DSM-IV major depressive disorder and a baseline Montgomery Asberg Depression Rating Scale score > or =20 were randomly assigned to treatment with paroxetine (to 60 mg/day) or desipramine (to 30 mg/day) in a 3-to-1 ratio, respectively. Norepinephrine and 5-HT transporter function were assayed by using human transporter transfected cells in the presence of serum collected at baseline and the end of each treatment week. Data from 36 patients were analyzed.

RESULTS

Paroxetine decreased norepinephrine uptake to 73% of control (27% inhibition) at an average serum concentration of 100 ng/ml and 57% of control (43% inhibition) at 200 ng/ml. Uptake of 5-HT was decreased to less than 15% (greater than 85% inhibition) of control at these paroxetine concentrations. Desipramine decreased norepinephrine uptake to near maximal 15% of control (85% inhibition) at 100 ng/ml. Uptake of 5-HT was decreased to 82% of control (18% inhibition) at 100 ng/ml and 49% of control (51% inhibition) at 500 ng/ml.

CONCLUSIONS

Paroxetine, currently classified as a selective 5-HT reuptake inhibitor, can act as a 5-HT/norepinephrine uptake inhibitor in vivo. The clinical significance of this action on norepinephrine uptake is currently unknown, but this action may contribute to the broad therapeutic efficacy of paroxetine in the treatment of depression, panic disorder, social anxiety disorder, posttraumatic stress disorder, and generalized anxiety disorder.

Allopregnanolone levels and symptom improvement in severe premenstrual syndrome

Allopregnanolone is a neuroactive metabolite of progesterone and a barbiturate-like modulator of central gamma-aminobutyric acid receptors that modify a range of behaviors, including the stress response. The aim of this study was to determine the association of allopregnanolone levels with improvement of mood and behavioral symptoms following antidepressant treatment for severe premenstrual syndrome. A second exploratory aim was to determine whether allopregnanolone levels differed between antidepressant and placebo treatments. Serum samples from 46 women who were treated with sertraline, desipramine, or placebo in double-blind conditions were assayed. Improvement was assessed as the percent change from the pretreatment baseline in premenstrual symptoms, which were rated daily by the subjects. Twenty-seven samples were from improved subjects and 19 samples were from unimproved subjects following 2 to 3 months of double-blind treatment. Posttreatment allopregnanolone levels were significantly lower in the improved compared with the unimproved subjects. Improvement was also significantly associated with lower allopregnanolone levels for premenstrual depression and appetite changes. Improvement remained significantly associated with lower allopregnanolone levels after adjustment for treatment, cycle day of blood draw, age, and the interaction of treatment and cycle day. These preliminary results offer the first placebo-controlled evidence of association between allopregnanolone levels and premenstrual syndrome treatment response and suggest the importance of further study of the associations of allopregnanolone with premenstrual syndromes and the role of allopregnanolone in response to antidepressant medications.