Treatment-resistant depression and Axis II comorbidity

BACKGROUND

Researchers of unipolar depression have speculated that personality disturbance is a contributing factor in the development of treatment resistance. The purpose of this study was to compare the prevalence of Axis II disorders between a sample of rigorously defined, treatment-resistant depressed outpatients and a sample of depressed outpatients not having experienced treatment resistance.

METHODS

53 patients with treatment-resistant depression (TRD) and 105 patients with non-treatment-resistant depression (non-TRD) were recruited through respective outpatient clinical trials at the Massachusetts General Hospital's Depression Clinical and Research Program. Diagnosis of Major Depressive Disorder was made using the Structured Clinical Interview for the DSM-III-R, personality disorders were assessed using the Structured Clinical Interview for DSM-III-R Personality Disorders, and antidepressant treatment resistance was defined using the McLean Hospital Antidepressant Treatment Record. Participants from both studies were matched for baseline HAM-D-17 total score and gender. Multiple chi-square analysis was used to compare frequencies of Axis II disorders between TRD and non-TRD patients as well as to compare categorical baseline demographic variables. Unpaired t tests were used to compare baseline demographic and clinical variables measured in a continuous manner.

RESULTS

Non-TRD patients had a higher rate of obsessive-compulsive personality disorder than TRD patients, but this difference was not statistically significant after adjusting for multiple comparisons. No other differences were found to be statistically significant. Range of Axis II comorbidity was 0.0-30.2% for TRD patients and 2.9-37.1% for non-TRD patients.

CONCLUSIONS

In this sample, treatment resistance in a current major depressive episode was not associated with an increased rate of Axis II disorders. Strengths of this study include the use of structured interview instruments to assess Axis I and II conditions, and having the two study groups matched for gender and baseline severity of depression. Limitations of this study include a modest sample size and reliance on DSM personality constructs.

Interaction of stress and noradrenergic drugs in the control of picrotoxin-induced seizures

To evaluate the possible role of noradrenergic system in the anticonvulsant effect of swim stress, the mice were prior to exposure to swim stress and the i.v. infusion of picrotoxin, pre-treated with desipramine (a noradrenaline reuptake inhibitor), N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4, a neurotoxin which destructs noradrenergic axons) or alpha-methyl-p-tyrosine (alpha-MPT, an inhibitor of catecholamine synthesis) and the latency to the onset of two convulsant signs and death was registered. While in control unstressed animals desipramine (20 mg/kg i.p.) and alpha-MPT (200 mg/kg i.p.) failed to affect, DSP-4 (50 mg/kg i.p., given 3 weeks prior to experiment) tended to decrease the dose of picrotoxin needed to produce tonic hindlimb extension (THE) and death. Swim stress prolonged the latency, i.e. increased (64-116% above control) the dose of picrotoxin needed to produce convulsant signs and death. In swim stressed mice desipramine enhanced the doses of picrotoxin needed to produce running-bouncing clonus (RB clonus), THE and death. alpha-MPT and DSP-4 pre-treatment failed to prevent the anticonvulsant effect of stress. Moreover, the effect of stress was greater in DSP-4 pre-treated mice. Although further studies are needed, the results suggest that the integrity of noradrenergic system is not substantial for the anticonvulsant effect of stress.

The SSRIs drug Fluoxetine, but not the noradrenergic tricyclic drug Desipramine, improves memory performance during acute major depression

Accumulating evidence suggests that noradrenergic and serotonergic drugs are equally effective in ameliorating the depressive symptoms of major depression. Major depression is associated also with memory impairments, but the comparative effects of the antidepressant drugs on memory are not clear. We previously found that serotonergic neurotransmission is of particular importance for some aspects of episodic memory. We set out to test whether treatment with the selective serotonergic drug Fluoxetine (Prozac) would be advantageous in this respect over treatment with the selective noradrenergic tricyclic antidepressant drug Desipramine (Deprexan). Seventeen patients with major depressive episode, randomly assigned for treatment with either Fluoxetine (n = 8) or Desipramine (n = 9), were assessed for their clinical situation and for memory performance at the beginning of treatment, after 3 weeks, and after 6 weeks of pharmacological treatment. We found that although clinically both drugs were equally effective, the improvement of memory performance in the Fluoxetine-treated patients was significantly greater compared with that of the Desipramine-treated patients. The results support the role of serotonin in memory. More studies in larger samples of patients are required, but it may be that in cases where memory impairment is a major symptom, it would be beneficial to consider serotonergic antidepressant drugs for treatment. Furthermore, in cases where, for various reasons, the treatment of choice is noradrenergic, it may be worthwhile to consider a supplementary serotonergic drug to improve memory deficits.

Gabapentin: new indication. In postherpetic neuralgia when amitriptyline fails

(1) Postherpetic pain is infrequent, but the incidence increases with age. (2) The reference treatment for postherpetic pain is oral amitriptyline or desipramine. (3) Gabapentin, an antiepileptic agent, is the first drug to be granted specific approval in France for the treatment of postherpetic pain. (4) In two placebo-controlled trials, gabapentin at a dose of between 1 800 and 3 600 mg/day halved the intensity of pain in about one in three patients. In comparison, pain improved in about 50% of patients taking amitriptyline in clinical trials. (5) Both gabapentin and amitriptyline provoke sedation, but dizziness and peripheral oedema are more frequent on gabapentin, while atropinic effects predominate with amitriptyline. (6) Daily treatment is 10 times more costly in France. (7) In practice, the standard treatment of postherpetic pain remains oral amitriptyline or desipramine. Gabapentin is an alternative, given its different safety profile.

Double-blind study of high-dose fluoxetine versus lithium or desipramine augmentation of fluoxetine in partial responders and nonresponders to fluoxetine

In a previous study, of 41 depressed patients who had not responded to fluoxetine 20 mg/day, 53% were treated with high-dose fluoxetine (40-60 mg/ day) and responded (i.e., their 17-item Hamilton Rating Scale for Depression [HAM-D-17] score was <7) versus 29% and 25% of patients treated with fluoxetine plus lithium (300-600 mg/day) or fluoxetine plus desipramine (25-50 mg/day), respectively. We wanted to assess whether these findings could be replicated in a larger sample of depressed outpatients. We identified 101 outpatients with major depressive disorder (52 men and 49 women; mean age, 41.6 + 10.6 years) who were either partial responders (n = 49) or nonresponders (n = 52) to 8 weeks of treatment with fluoxetine 20 mg/ day. These patients were randomized to 4 weeks of double-blind treatment with high-dose fluoxetine (40-60 mg/day), fluoxetine plus lithium (300-600 mg/day), or fluoxetine plus desipramine (25-50 mg/day). In the overall group of patients (N = 101), there was no significant difference in response rates across the three treatment groups (high-dose fluoxetine, 42.4%; fluoxetine plus desipramine, 29.4%; fluoxetine plus lithium, 23.5%). Dropout rates were also comparable, ranging from 9.1% (high-dose fluoxetine) to 14.7% (fluoxetine plus desipramine and fluoxetine plus lithium). There were also no significant differences in response rates across the three treatment groups among partial responders (high-dose fluoxetine, 50.0%; fluoxetine plus desipramine, 33.3%; fluoxetine plus lithium, 33.3%) and nonresponders (high-dose fluoxetine, 35.3%; fluoxetine plus desipramine, 26.3%; fluoxetine plus lithium, 12.5%). At the end of the study, the mean lithium level was 0.37 + 0.15 mEq/L (n = 27; range, 0.1-0.8 mEq/L) among lithium-treated patients, and the mean desipramine level was 104.7 + 58.8 ng/mL (n = 22; range, 25-257 ng/mL). There were no significant relationships between lithium or desipramine blood levels and degree of improvement (as measured by the change in HAM-D-17 score). We found no significant differences in efficacy among these three treatment strategies among patients who had failed to respond adequately to 8 weeks of treatment with fluoxetine 20 mg/day, although the high-fluoxetine group was associated with nonsignificantly higher response rates in both partial responders and nonresponders.

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

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

A double-blind comparison of desipramine and placebo in children and adolescents with chronic tic disorder and comorbid attention-deficit/hyperactivity disorder

BACKGROUND

Currently, there is no consensus on the best therapeutic approach to chronic tic disorders and comorbid attention-deficit/hyperactivity disorder (ADHD). To address this issue, we evaluated the tolerability and efficacy of the noradrenergic tricyclic antidepressant desipramine hydrochloride in the treatment of children and adolescents with chronic tic disorders and comorbid ADHD.

METHODS

Forty-one children and adolescents with chronic tic disorders, including Tourette disorder and comorbid ADHD, were studied in a 6-week, double-blind, placebo-controlled, parallel trial. Desipramine was titrated weekly up to 3.5 mg/kg per day. We rated ADHD and tic symptoms weekly and monitored adverse effects, laboratory findings, and cardiovascular parameters.

RESULTS

Treatment with desipramine (mean total daily dose, 3.4 mg/kg per day) was well tolerated without meaningful adverse effects. Desipramine significantly reduced core symptoms of ADHD (ADHD Rating Scale; 42% decrease from baseline relative to placebo, P<.001), with equal response in inattentive symptoms and hyperactive/impulsive symptoms (P<.001 for both). The ADHD response rate was robust (71% vs 0%; desipramine vs placebo, P<.001). Likewise, desipramine significantly reduced tic symptoms (Yale Global Tic Severity Scale; 30% decrease from baseline relative to placebo, P<.001), with equal response in motor and phonic tic symptoms (P<.01 for both). The tic response rate was substantial (58% vs 5%; desipramine vs placebo, P<.001). There were small but statistically significant differences between desipramine and placebo in heart rate and blood pressure.

CONCLUSIONS

Treatment with desipramine was well tolerated and was associated with robust clinically significant reductions in tic and ADHD symptoms in children and adolescents with chronic tic disorders and ADHD diagnoses.

Antidepressant reversal of interferon-alpha-induced anhedonia

Interferon-alpha(IFN-alpha) is used clinically in the treatment of several pathologies such as hepatitis C and various cancers. The positive therapeutic potential is however often limited by negative secondary effects which include major depression, one of the cardinal symptoms of which is anhedonia which has been operationalized as a decreased sensitivity to rewards (inability to experience pleasure). Previous studies have demonstrated the existence of anhedonia in rats following an acute injection of IFN-alpha at doses corresponding to those used in clinical applications. If this previously demonstrated anhedonia is indeed part of a depression syndrome in rats, this behavioural symptom should be reversible by the administration of antidepressants. The objective of the present experiment was to determine whether two commonly used antidepressants (desipramine and fluoxetine) were effective in ameliorating IFN-alpha-induced anhedonia in rats. The experiment consisted of two phases. In the first, the effects of daily systemic injections of 104 units/kg of IFN-alpha (or vehicle) were evaluated with the three-bottle (1%, 8%, and 32%) sucrose-consumption test. In the second phase of the experiment, in addition to continued injections of IFN-, different groups received daily injections of desipramine (7.5 mg/kg ip), fluoxetine (7.5 mg/kg ip), or vehicle. The IFN-alpha injections during Phase 1 resulted in clear anhedonia, as expressed by increased consumption of the 32% solution and decreased consumption of 1% over the 33 days of this phase. After 15 days of antidepressant treatments, 32% sucrose consumption returned to baseline values. We have therefore confirmed that IFN-alpha-induced anhedonia is susceptible to reversal following chronic antidepressant treatment and thus it may appear timely to consider the prophylactic use of such in particular patients prescribed IFN in the clinic.

Influence of ACTH on the effects of imipramine, desipramine and lithium on duration of immobility of rats in the forced swim test

We examined the effects of adrenocorticotropic hormone (ACTH) on the immobilization of rats in the forced swim test with the administration of imipramine, desipramine, or lithium. A single administration of either imipramine (10-30 mg/kg, i.p.) or desipramine (30 mg/kg, i.p.) significantly decreased the duration of immobility in normal rats in a dose-dependent manner. Lithium (10-100 mg/kg, p.o.), however, had no affect on the performance of rats in the forced swim test. ACTH (100 microg/day), administered subcutaneously to rats for 1, 3, 7, and 14 days, had no apparent effect on the duration of immobility in this test. The immobility-decreasing effect induced by a single administration of either imipramine (10-30 mg/kg, i.p.) or desipramine (30 mg/kg, i.p.) was blocked by chronic administration of ACTH for 3-14 days. The reduction of immobility, induced by chronic administration of imipramine (10 mg/kg, i.p.) for 15 days, was blocked by treatment with ACTH for 14 days. When lithium (100 mg/kg, p.o.) was administered for 15 days concurrently with imipramine (10 mg/kg, i.p.), we observed a significant decrease in immobility in rats treated with ACTH for 14 days. We suggest that chronic treatment of rats with ACTH may prove to be an effective model of tricyclic antidepressants-treatment-resistant depression.

Brain 5-HT receptor system in the stressed infant rat: implications for vulnerability to substance abuse

Clinical and epidemiological studies have found an association between aversive experiences early in life and an increased risk for depression, anxiety and substance abuse. In order to elucidate the mechanisms by which adverse life events are translated into behavioral and psychological abnormalities, we used a rat model to study the impact of chronic injection and 24 h maternal deprivation on the developing rat brain. Specifically, we investigated the regulation of molecules related to the 5-HT (5-HT) system and studied the effect of desipramine administration on animals that were maternally deprived (DEP) on day 13 of life compared with non-deprived animals. We found that maternal deprivation caused an enhanced corticosterone response to an acute stress. Maternally deprived animals also showed a decrease in corticosteroid receptors and an increase in 5-HT 1A and 1B receptors restricted to the CA1 region of the hippocampus. Desipramine prevented the maternal deprivation induced up-regulation of the 5-HT 1B receptor and the enhanced adrenocortical response observed in these animals. Interestingly, non-deprived animals receiving chronic injections showed a decrease in hippocampal 5-HT1B receptor mRNA. At 80 days of age, a group of animals that were treated as infants were given the option of drinking from two identical water bottles, one bottle contained tap water, while the second contained ethanol at increasing concentrations. Animals that received chronic injections during the newborn period consumed more alcohol than those that were not injected. On the other hand, maternal deprivation did not have an impact on alcohol consumption. Alcohol preference has implications to the organism since studies of drug self-administration in laboratory animals have shown that ethanol ingestion is positively related to the use of other drugs, principally opioids and psychostimulants. Our findings suggest that the quality and/or chronicity of early life stressors can influence the neurobiological substrates that may trigger and/or predispose individuals to substance abuse in adulthood.

Hyperactive phosphoinositide signaling pathway in platelets of depressed patients: effect of desipramine treatment

There is some evidence to suggest that certain neurotransmitter receptors, such as adrenergic and serotonergic receptors and receptor-linked signaling systems, may be altered in depression. Serotonin(2A) and alpha(2)-adrenergic receptors are linked to the phosphoinositide (PI) signaling system in platelets and brain. To examine if the PI signaling system is altered in depression, we studied thrombin- and sodium fluoride-stimulated inositol phosphate(1) (IP(1)) formation before and during desipramine (DMI) treatment in platelets of depressed patients and normal control subjects. We determined thrombin- and sodium fluoride-stimulated IP(1) formation in platelets obtained from hospitalized depressed patients during a drug-free baseline period and after 6 weeks of DMI treatment, and drug-free non-hospitalized normal control subjects. Depressed subjects were diagnosed according to DSM-IV criteria, and severity of illness was assessed with the Hamilton Depression Rating Scale. We observed that thrombin-stimulated IP(1) formation in platelets of depressed patients was significantly higher compared with that of normal control subjects. There were no significant differences in sodium fluoride-stimulated IP(1) formation between depressed patients and normal control subjects. We also did not find any significant effect of treatment with DMI on either thrombin- or sodium fluoride-stimulated IP(1) formation in platelets of depressed patients, which continued to be significantly higher after 6 weeks of treatment with DMI, compared with normal control values. Our studies found a hyperactive PI signaling system in platelets of depressed patients. This hyperactive system may be related either to an increased number of thrombin receptors or to a generalized overstimulation of this pathway; however, since we did not observe any differences in sodium fluoride-stimulated IP(1) formation, it appears that, although the sites distal to the receptors may be altered, this abnormality is probably not related to the abnormalities in G proteins.

Psychiatric issues in the management of patients with HIV infection

Approximately 1 million persons are now infected with human immunodeficiency virus (HIV) in the United States. Evidence exists that psychiatric disorders are common in patients with HIV and that these patients may not receive optimal care because their psychiatric disorders are a barrier to medical care, communication with clinicians, and adherence to medical recommendations. We describe herein a complex case seen at The Johns Hopkins Hospital with several psychiatric conditions that are common in our HIV clinic population. We describe the collaborative treatment of the patient by a multidisciplinary team including both medical and mental health practitioners. We briefly describe a coherent diagnostic and treatment approach to patients in HIV clinics and the supporting rationale from the literature. We discuss the need for comprehensive evaluation, a multidisciplinary treatment team, and therapeutic optimism.

Cerebral blood flow in obsessive-compulsive patients with major depression: effect of treatment with sertraline or desipramine on treatment responders and non-responders

We examined the effects of sertraline and of desipramine on patients with OCD and comorbid major depressive episodes at study entry. Sixteen patients, 9 receiving sertraline and 7 desipramine, received HMPAO SPECT scans while free of medication and after 12 weeks of treatment. Patients on sertraline showed significantly reduced regional cerebral blood flow (rCBF) in the right prefrontal and temporal regions. Patients on desipramine showed more diffuse rCBF reductions in frontal and temporal regions, more so in the left side. In a second analysis, patients who had a symptom reduction on the Yale-Brown Obsessive Compulsive Scale (YBOCS), irrespective of the type of medication, were retrospectively classified as 'responders' to treatment. Eleven patients were 'responders' and 5 'non-responders'. Before being medicated, responders differed from non-responders through higher rCBF in prefrontal regions, mostly on the left, and higher rCBF in the cingulate and basal ganglia bilaterally. After 12 weeks of treatment, responders showed a diffuse reduction of rCBF in prefrontal regions while non-responders showed only a few scattered low-frequency responses. Thus, higher prefrontal and subcortical activity was associated with better response to drug treatment. In addition, clinical change, but not the administration of medication as such, was associated with a decrease of prefrontal rCBF.

Enhancement of noradrenergic neural transmission: an effective therapy of myasthenia gravis: a report on 52 consecutive patients

Neurochemical, neuroautonomic and neuropharmacological assessments carried out on all our myasthenia gravis (MG) patients showed that they presented a neural sympathetic deficit plus excessive adrenal-sympathetic activity. These abnormalities were registered during the basal (supine-resting) state, as well as after several stress tests (orthostasis, exercise, oral glucose and buspirone). In addition, MG patients showed increased levels of free-serotonin (f5HT) in the plasma, supposedly associated with the increased platelet aggregability which we found in all MG patients. As the above trio of neurochemical disorders (low noradrenergic-activity + high adrenergic-activity + increased f-5HT plasma levels) is known to favor Th-1 immunosuppression + Th-2 predominance, we outlined a neuropharmacological strategy for reverting the above neurochemical disorder. This treatment provoked sudden (acute), and late sustained improvements. Acute effects have been attributed to the increase of alpha-1 activity at the spinal motoneuron level. Late improvements always paralleled a significant normalization of immunological disorders. Complete normalization was registered only in non-thymectomized MG patients.

Comparison of desipramine and cognitive/behavioral therapy in the treatment of elderly outpatients with mild-to-moderate depression

The authors evaluated the efficacy of desipramine-alone, vs. cognitive/behavioral therapy-alone (CBT) vs. a combination of the two, for the treatment of depression in older adult outpatients. Patients (N=102) meeting criteria for major depressive disorder were randomly assigned to one of these three treatments for 16 to 20 therapy sessions. All treatments resulted in substantial improvement. In general, the CBT-Alone and Combined groups had similar levels of improvement. In most analyses, the Combined group showed greater improvement than the Desipramine-Alone group, whereas the CBT-Alone group showed only marginally better improvement. The combined therapies were most effective in patients who were more severely depressed, particularly when desipramine was at or above recommended stable dosage levels. The results indicate that psychotherapy can be an effective treatment for older adult outpatients with moderate levels of depression.

Development of a depersonalization severity scale

Our aim was to develop a clinician-rated scale assessing depersonalization severity for use in clinical trials of Depersonalization Disorder and trauma-related disorders in general. The 6-item Depersonalization Severity Scale (DSS) was administered to 63 participants with DSM-IV Depersonalization Disorder as diagnosed by the SCID-D, and its psychometric properties were examined. The sensitivity of the DSS and of the Dissociative Experiences Scale (DES) to treatment change was assessed in blinded, controlled settings. Individual items were widely distributed across the severity range. Interrater reliability was excellent and internal consistency was moderate. The DSS had high convergent and discriminant validity and was sensitive to treatment change. The DES was also sensitive to treatment change. We recommend piloting the DSS in future treatment trials of trauma-spectrum disorders.

Cardiovascular effects of tricyclic antidepressants in childhood asthma: a case series and review

Children with asthma frequently have significant anxiety and depression that interfere with treatment outcome. Although the use of antidepressants may be helpful, in the one published study of antidepressant use in pediatric asthma, significant side effects necessitated discontinuance; these side effects were increased motor activity, impulsive behavior, insomnia, postural hypotension, premature auricular contractions, diastolic hypertension, and generalized seizure. The objective of this retrospective chart review was to examine whether antidepressants could be tolerated and administered safely to children on asthma medications. Forty pediatric inpatients (mean age 13.3 years, range 7-19) with varying levels of asthma severity (5 mild, 11 moderate, 24 severe) and an average duration of asthma treatment of 10.0 years were administered antidepressants while also taking an average of 5 medications for asthma (range 2-7). Ten of the patients had an additional comorbid medical diagnosis. There were 17 children diagnosed with a primary affective disorder; 7 with a primary anxiety disorder; and 16 with both an affective and anxiety disorder. Thirty-six children ultimately were continued on an antidepressant: 13 on desipramine, 9 on nortriptyline, 6 on imipramine, 4 on fluoxetine, 3 on bupropion, and 1 on sertraline. Significant cardiovascular side effects (tachycardia, hypertension, and postural hypotension) occurred in 4 subjects on tricyclic antidepressants (TCAs) and 1 subject on a non-TCA (fluoxetine); 3 of these subjects were able to continue treatment with an antidepressant. Two subjects were taken off antidepressants because of hypomanic symptoms (increased motor activity, mood lability, impulsive behavior, and insomnia). No medications were discontinued because of electrocardiogram changes, arrhythmias, or seizures. Doses of TCAs were comparable to those in previous studies, but the asthma medications differed. Discussion of current anti-asthmatic medications and potential for interactions with antidepressants is included.

Group housing of mice increases immobility and antidepressant sensitivity in the forced swim and tail suspension tests

The forced swim test and tail suspension test are often used in laboratory practice to identify compounds that possess antidepressant-like activity. This experiment was conducted to determine whether housing conditions per se influence the response of mice in these antidepressant screening procedures. Male NIH Swiss mice were housed individually or in groups (five per cage) for 8 weeks prior to testing. After 8 weeks, the animals were exposed to the forced swim and tail-suspension tests. Group housed mice displayed high levels of immobility in the forced swim and tail suspension tests. Desipramine injection 60 min prior testing, in doses 7.5 and 15 mg/kg, produced significant reductions in the immobility time in forced swimming and tail suspension tests. Individually housed mice, when exposed to these tests, displayed lower levels of immobility with a magnitude comparable to the effect of desipramine in group housed mice. Desipramine given to individually housed mice did not reduce the duration of immobility either in the forced swim test or in the tail suspension test. These results indicate that both tests are sensitive to housing conditions. This observation suggests that long lasting group housing may be critical to the behavioral response in these preclinical screening procedures in mice.

The drug-placebo response curve: a new method for assessing drug effects in clinical trials

Unlike many other areas of medicine, psychiatric clinical trials have no gold standard laboratory tests with which to measure drug effects. Although reliable and valid psychometric measures are available, the standard analysis of such measures obscures the clinical relevance of drug effects. In this study, the authors sought to address this problem by developing a graphical display called the drug-placebo response curve. The features of the drug-placebo response curve are described by applying it to a previously published, controlled clinical trial of desipramine in the treatment of adults with attention-deficit/hyperactivity disorder. Unlike the standard analysis, the drug-placebo response curve showed that desipramine was effective over the full range of response and that it prevented worsening, in addition to increasing the likelihood of improvement. The drug-placebo response curve provides clinically relevant information about the effect of drugs on continuous outcomes in controlled clinical trials.

Therapeutic effects of imipramine are counteracted by its metabolite, desipramine, in patients with generalized anxiety disorder

Imipramine has been shown to reduce anxiety in patients with generalized anxiety disorder (GAD). However, some properties of imipramine may diminish or counteract its anxiolytic effects. The authors previously found that the greater the reduction in cardiac vagal control after 6 weeks of imipramine treatment, the smaller the improvement in anxiety-related symptoms. The purpose of this study was to determine whether the authors' previous findings were replicable and to gather information on the plasma levels of imipramine, desipramine (the major metabolite of imipramine), and anticholinergic levels. Fourteen patients with GAD were administered imipramine for 6 weeks. Their scores from self-administered and investigator-administered rating scales were obtained before and after the treatment, and the changes in these scores were contrasted with the changes in cardiac vagal tone, along with the absolute plasma levels of imipramine, desipramine, and anticholinergic activity at the end of week 6. The authors observed a greater improvement in symptoms of anxiety in those who showed the smallest decreases in cardiac vagal tone and in those who showed the smallest increases in desipramine and anticholinergic plasma levels. Moreover, strong relationships were observed between desipramine and anticholinergic levels. These results demonstrate that imipramine not only has therapeutic effects, but it may also have properties that result in physiologic states that counteract its therapeutic effects. Future research should investigate the direct anticholinergic effects of desipramine and determine whether there is a parallel between the anticholinergic effects and the clinical outcome of other pharmacologic treatments, including antidepressants with predominantly norepinephrine or serotonin reuptake inhibitory properties.

Effect of tolcapone on the haemodynamic effects and tolerability of desipramine

BACKGROUND AND PURPOSE

To determine the changes in haemodynamics, tolerability and pharmacokinetics that may occur when a combination of tolcapone and levodopa/carbidopa are given with desipramine.

METHODS

In a crossover study, 22 healthy subjects received desipramine during two 13-day treatment periods (25 mg t.i.d. for 3 days and 50 mg t.i.d. for 10 days), with a washout period of 10-15 days. Subjects received levodopa/carbidopa (100 mg/25 mg t.i.d. for 5 days, days 9-13) and concomitant, double-blind, randomized treatment with either tolcapone (200 mg t.i.d.) or placebo.

RESULTS

No significant pharmacodynamic and pharmacokinetic interactions occurred between tolcapone and desipramine. Adverse events were predictable based on the known effects of the individual drugs.

CONCLUSIONS

Tolcapone can be combined with levodopa/carbidopa and desipramine in patients with Parkinson's disease.