Clinical measures of rapid onset of action

The benefits of an antidepressant with an early or rapid onset of action include a more rapid resolution of the debilitating symptoms of depression, a potential reduction in the risk of suicide and cost savings associated with a reduction in hospitalization. While these benefits are valuable, this promise has yet to be fulfilled by any antidepressant. Venlafaxine is a unique serotonin-noradrenaline reuptake inhibitor (SNRI) which produces rapid and prolonged desensitization of β-adrenergic receptors in preclinical studies after both acute and chronic administration of venlafaxine. Results from placebo-controlled and active comparator clinical studies provide evidence that venlafaxine may have an early onset of activity which is most apparent at higher dosages. The early onset is most apparent with rapid escalation of the venlafaxine dosage, and the incidence, therefore, of side effects tends to be higher early after initiating therapy with venlafaxine. Thus, venlafaxine may fill the long awaited need for an antidepressant with an early onset of action.

Long-term management of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic debilitating condition that requires long-term treatment. The selective serotonin reuptake inhibitors (SSRIs) appear to be associated with similar levels of efficacy to clomipramine in short-term treatment, but to have significant tolerability advantages. The results of the long-term controlled studies on clomipramine, fluvoxamine, fluoxetine and sertraline are reviewed. They demonstrate a significantly better outcome for anti-obsessional drugs than placebo. The absence of adequate long-term controlled studies on pharmacotherapy strengthen the grounds for recommending pharmacotherapy as the optimal approach for long-term treatment of OCD. The SSRIs would appear to be the treatment of choice in OCD in view of their tolerability and safety advantages compared with clomipramine.

Recovery from depressive illness does fit an exponential model

A very large number of therapeutic trials of antidepressant drugs have been reported in the scientific literature. Until now, the comparison of one drug with another, or with placebo, has been performed typically by comparing the scores on depression rating scales of the two groups of patients at fixed points of time after the beginning of therapy. It was postulated in 1989 that the curves of the recovery scores followed an exponential curve of the formula y = ae-bx + c. This hypothesis was tested in a double-blind controlled trial of the antidepressant minaprine, with the use of the scores on the Hamilton Rating Scale for Depression (HAM-D). We found that the correlation coefficient, Pearson's r, between the log of the HAM-D value and the week number of the study was -0.99. This gives a coefficient of determination of 0.98, which makes it clear that the model adequately fits the data. We conclude that the use of the formula gives a method of testing the statistical significance of the difference between treatments as a valuable alternative to traditional tests. We believe that this would give a much more sensitive discrimination between treatments because all of the data points are used to calculate a single parameter--the slope of the curve.

Efficacy and tolerability of milnacipran: an overview

The relative benefits and risks of milnacipran, a novel antidepressant which selectively inhibits the reuptake of serotonin and noradrenaline, have been evaluated in comparative trials against tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs). A total of 2462 patients with major depressive disorders have been investigated. At the optimal dose (50 mg twice a day), the efficacy of milnacipran was equivalent to that of the TCAs, with response rates of approximately 65% in both cases. Milnacipran was consistently effective against all of the principal elements of depression (anxiety, cognitive function, sleep and psychomotor retardation), and did not produce sedation or the emergence of suicidal thoughts. The Clinical Global Impression (CGI-3) score, a measure of the overall therapeutic impact of a treatment, was significantly higher with milnacipran than with TCAs (1.98 versus 1.84, p < 0.05). TCAs were associated with a higher frequency of adverse events than milnacipran, particularly with respect to anticholinergic-like effects; dysuria was the only adverse event occurring twice as frequently with milnacipran than with TCAs. Compared with TCAs, milnacipran was also associated with a lower incidence of cardiovascular adverse events. No haematological abnormalities occurred during treatment with milnacipran, and the incidence of abnormal liver function tests tended to be lower with milnacipran than with TCAs. In comparisons with SSRIs, milnacipran produced significantly higher response rates. The CGI-3 scores were significantly higher in milnacipran-treated patients (2.64 versus 2.32, p < 0.05). The adverse event profiles of the two treatments were similar, as was the incidence of abnormal liver function tests. These studies suggest that milnacipran offers clinical advantages over TCAs in terms of tolerability, and over SSRIs in terms of efficacy. In particular, the lack of cardiovascular adverse events appears to offer advantages in cases of deliberate overdose. To date, 15 such overdoses have occurred; none was fatal and each had a favourable outcome. The reproducible pharmacokinetic characteristics of milnacipran present further advantages over both groups of agents, due to lack of drug accumulation and a low risk of drug interactions.

Economic analysis of treating depression with nefazodone v. imipramine

BACKGROUND

It is estimated that treating diagnosed depression costs 420 pounds million annually in England and Wales. This economic study analyses treatment of major depression with nefazodone v. imipramine.

METHOD

The study updates a previously published model using data obtained from the continuation phase of a double-blind one-year placebo-controlled comparison of nefazodone with imipramine.

RESULTS

Annual costs for nefazodone are lower than those for imipramine, 218 pounds compared to 254 pounds; the cost per successfully treated patient is also lower for nefazodone than for imipramine, 242 pounds v. 323 pounds. Varying the resources included in the treatment patterns still results in lower costs for nefazodone treatment.

CONCLUSIONS

Based on clinical trial data for patients completing six to eight weeks of depression treatment and followed for at least one year, the model shows that the annual costs of nefazodone are lower than those for the less expensive imipramine.

Moclobemide in the treatment of social phobia

Social phobia is a common disorder which is associated with considerable suffering and impairment. Effective treatments have now been developed and they represent an important advance in the management of the disorder. Moclobemide is a reversible inhibitor of monoamine oxidase A (RIMA) which has an established place in the treatment of depression. The efficacy of moclobemide in social phobia has been demonstrated in short-term treatment for up to 12 weeks in three placebo-controlled studies. It has also proved to be effective in long-term treatment in a placebo-controlled study and in open treatment studies. This paper reviews the efficacy of moclobemide in social phobia.

Need for treatment and measurement of outcome: workshop report 2

--w?3w--w--x@Łt#-3w--w?3w--w?3;;;;;ve been underestimated in the past. It is now accepted that social phobia causes important occupational and social dysfunction and the recognition that effective treatments are available represents considerable advance. Measuring outcome is a necessary part of the assessment of the usefulness of treatment and new rating scales have been developed to measure both improvement in symptoms and changes in disability. Both self-rated and observer-rated scales have been developed, though observer scales tend to be preferred because they are less prone to interindividual variability.

The antidepressant efficacy of citalopram

Depression is a long-term illness requiring psychopharmacological treatment over long periods of time. Treatments need to be effective and safe, but in an illness requiring long-term medication, acceptability to patients must also be addressed. Data from eight placebo-controlled studies addressing short-term efficacy and two placebo-controlled studies of long-term (6 months) treatment have demonstrated the antidepressant efficacy of citalopram. Fourteen studies comparing citalopram with a reference antidepressant have provided supporting evidence of efficacy. In all, 3905 patients have been included in clinical efficacy studies, in which 2579 patients have been treated with citalopram, 486 with placebo and 840 with a reference antidepressant. The recommended dose of 20 mg appears appropriate for most patients, with the option of raising the dose in non-responders, particularly if they have more severe depression.

Efficacy in long-term treatment of depression

Available evidence suggests that antidepressants need to be continued on a long-term basis after the acute response. Premature discontinuation soon after symptomatic response is associated with the return of depression (relapse) in many patients. One efficacy measure of an antidepressant required by many regulatory authorities prior to approval of the agent is the ability of the antidepressant to continue the acute response compared with a placebo control. The reference tricyclic antidepressants (TCAs) amitriptyline and imipramine both have been shown to be effective in this continuation phase, but there is surprisingly little evidence on the efficacy of the other TCAs. The serotonin selective reuptake inhibitors paroxetine, fluoxetine, sertraline, and citalopram, as well as nefazodone, a new antidepressant with a dual mechanism of action that is classified as a serotonin receptor modulator, are effective compared with placebo. Placebo appears to be a good comparator in assessing the long-term efficacy of antidepressants. For example, in an assessment of the long-term efficacy of citalopram, patients who responded while taking placebo and were continued on placebo treatment were compared with patients who responded to drug and were transferred to placebo. The relapse rates in both cases were similar, validating placebo as a useful control. Most studies of long-term efficacy use the discontinuation design in which patients are treated with an active drug until response is obtained and then are either continued on the active drug or switched to placebo in a random and blinded manner. Alternatively, studies with nefazodone have used the double-blind continuation design, which may be preferred because it avoids any confounding effects of the discontinuation of drug in a drug-responsive patient. For example, in acute studies, responders to treatment with nefazodone, imipramine, or placebo were continued on the same treatment under double-blind conditions for 1 year; both antidepressants were effective compared with placebo. This study design may be useful in providing an estimate of long-term efficacy that can be obtained relatively early in a drug development program. The length of treatment in the continuation phase of therapy is also of interest. The separation of drug and placebo efficacy is sharpest in the first 4 months, which is consistent with the recommendation that all treatment for depression should continue for a minimum of 4 to 6 months to prevent relapse after symptomatic response of the acute episode. After the continuation phase (relapse prevention), evolving evidence strongly indicates that antidepressant treatment should be continued in patients at risk for recurrence. Depending on the number of recurrences, lifelong prophylactic therapy may be warranted.

Safety of mirtazapine: a review

The clinical trial development programme of mirtazapine (Org 3770), performed in Europe and the United States, demonstrated an outstanding safety profile of this compound. The evaluation of the safety was based on data from all patients who took at least one dose of study medication during studies comparing mirtazapine with placebo, amitriptyline or other active comparators. A general indication of mirtazapine's safety is the significantly lower percentage of patients (65%) who complained of any adverse clinical experiences compared with the placebo- (76%) or amitriptyline-treated group (87%). Moreover, drop-out rates due to adverse clinical experiences were significantly lower than in the amitriptyline-treatment group. Mirtazapine has virtually no anticholinergic, adrenergic or typical selective serotonin reuptake inhibitor (SSRI) side effects. The only significantly higher incidences versus placebo were seen in the adverse clinical effects of drowsiness (23% versus 14%), excessive sedation (19% versus 5%), dry mouth (25% versus 16%), increased appetite (11% versus 2%) and weight increase (10% versus 1%). These complaints were typically mild and transient in nature, and decreased over time despite increased doses of mirtazapine. In contrast, significantly higher incidences of headache (5% versus 10%) and weight decrease (2% versus 6%), symptoms commonly seen in depressed patients, were recorded in the placebo-treated patients. Also, typical SSRI adverse events, such as nausea, vomiting, diarrhoea and insomnia, and symptoms of sexual dysfunction were registered less frequently in mirtazapine-treated patients than in the placebo-treated patients. Approximately 10% of the mirtazapine-treated patients in the clinical trial programme were older than 65 years. The pattern of adverse clinical experiences seen in this group of patients is fully in line with that seen in the overall patient population. The analysis of vital sign indices, i.e. blood pressure and heart rate, showed that no changes occurred with mirtazapine treatment; this pattern was fully comparable to that seen with placebo. Furthermore, very low incidences of clinically relevant changes in laboratory indices, such as the liver enzymes alanine aminotransferase and aspartate aminotransferase or neutropenia, were recorded in each treatment group. Mirtazapine has a very low seizure-inducing potential: only one case was recorded in a patient with a history of seizures during previous treatment with clomipramine. The low seizure-inducing potential combined with a lack of cardiotoxic properties allows safety in an overdose of mirtazapine, even in elderly patients. The only symptom seen in the patients taking an overdose of mirtazapine alone or in combination with other drugs was excessive but transient somnolence, which resolved spontaneously within a few hours. In conclusion, the new antidepressant mirtazapine offers clinicians a unique combination of strong efficacy and good safety.

First clinical experience with olanzapine (LY 170053): results of an open-label safety and dose-ranging study in patients with schizophrenia

Although neuroleptic drugs have proven value in the management of patients with schizophrenia, the existing drugs are far from ideal. The pharmacological profile of olanzapine (LY 170053, Lilly) in animal models suggests that it may be an effective antipsychotic drug in humans, with the potential for a reduced incidence of desirable extra-pyramidal side effects, compared to existing neuroleptics. The results of this first investigation of olanzapine in schizophrenic patients indicate that it has efficacy as an antipsychotic compound, relieving positive and negative features of schizophrenia. Olanzapine appears to have an acceptable degree of overall tolerability, and may be associated with a low incidence of extrapyramidal tract symptoms. It does not appear to be free of adverse effects on liver function.

Managing depression in the community

Community and practice nurses have a vital role to play in depressive illness. Depression is a very treatable illness; early detection requires a knowledge of symptoms. Patient education and monitoring of drug side-effects are essential aspects of the management of depression.

Rapid onset of action of venlafaxine

It is important to evaluate a new antidepressant in terms of its efficacy in relation to that of reference agents such as the tricyclics and monoamine oxidase inhibitors. Newer antidepressants have not been shown to be more effective than the reference agents, either in the proportion of patients in whom they produce a therapeutic response or in their speed of onset of antidepressant activity. The serotonin-noradrenaline reuptake inhibitor (SNRI) venlafaxine appears to offer some advantages in both of these areas. In a number of short-term placebo- and comparator-controlled trials, venlafaxine was shown to be as effective as, and in some cases more effective than, the reference antidepressants. These findings were also substantiated in meta-analyses of both short-term and long-term comparator-controlled studies. In terms of its onset of activity, venlafaxine was shown to produce statistically significant differences from placebo as early as Day 4 in a study in severely depressed in-patients with melancholia and by Week 1 in a study in out-patients with major depression. A rationale is presented to define the clinical relevance of these findings.

Reduction of suicidal thoughts with paroxetine in comparison with reference antidepressants and placebo

In order to determine whether paroxetine was associated with any increase in suicidal thoughts or acts all controlled studies of paroxetine were examined in a series of metanalyses. Paroxetine showed an advantage in reducing suicidal thoughts in all analyses compared with placebo. On the MADRS there was a significant advantage compared with active controls at weeks 1, 3, 4 and 6 (P < 0.01). There were significantly fewer emergent suicidal thoughts on paroxetine compared with placebo in all analyses, and a significant advantage for paroxetine compared with active controls on the MADRS. A significant advantage for active controls compared with placebo was seen only on the HAMD. In the analysis of the data from controlled studies and open extension studies of paroxetine calculated by patient year of exposure there were 2.8 times fewer suicides in the paroxetine-treated group compared with active control and 5.6 times fewer compared with placebo.

Citalopram in doses of 20-60 mg is effective in depression relapse prevention: a placebo-controlled 6 month study

The aim of the present study was to determine whether, in patients with depression who had responded favourably to the selective serotonin reuptake inhibitor citalopram, there was a therapeutic benefit in continuation treatment. Three hundred and ninety-one depressive patients were included in an open short-term citalopram treatment period. Only patients who responded to treatment at 8 weeks (total score of 12 or less on the MADRS scale) were randomized to the 24 week double-blind phase. Seventy-four patients were treated with placebo and 152 with citalopram at the same constant dose to which the patient had responded in the first phase. Relapse was defined as a total score of 25 or more on the MADRS scale. Twenty-one patients (13.8%) continuing to receive citalopram relapsed compared with 18 patients (24.3%) receiving placebo. The log rank test for survival data used to test the quality of relapse hazards between the placebo group and the citalopram group showed that patients treated with citalopram had a significantly lower relapse rate (p = 0.04). The results of this study are in general agreement with those of other studies on antidepressants, and support the hypothesis that full dose continuation is more effective than placebo in preventing relapse of depression.

Selecting the optimum therapeutic dose of serotonin reuptake inhibitors: studies with citalopram

Establishing the optimum therapeutic dose of a putative antidepressant is important to avoid unnecessarily high doses, which may be associated with increased frequency of severity of unwanted side effects, or too low a dose which may not achieve the best therapeutic effect. Flexible dose regimes that are often used in clinical trial programmes may lead to the use of too high a dose because of the attribution of response in depression to the higher dose used later in the study rather than being identified as a delayed response to a lower dose used earlier. Fixed dose studies provide a more reliable view of the dose response relationship and, where differences between doses are small, metanalysis of large databases may provide a useful tool for the establishing of the minimum therapeutic dose. Metanalysis of the placebo controlled results with citalopram demonstrated that the dose-response curves based on log odds ratios showed a very flat curve across the 20-60 mg range and that 20 mg appeared therefore to be the minimum effective dose. There was evidence that in some subgroups of depressed patients a better response may be seen with a higher dose. For example in patients with severe depression citalopram was effective compared with placebo in doses of both 20 mg and 40 mg. However there was a more pronounced therapeutic effect with the higher dose. Similar results have been reported with other selective serotonin reuptake inhibitors.

Antidepressant efficacy in relation to item analysis and severity of depression: a placebo-controlled trial of fluvoxamine versus imipramine

In this investigation, the antidepressant efficacy of fluvoxamine and imipramine was compared in a randomized, double-blind, placebo-controlled study lasting 4 weeks; 338 depressed patients were recruited at five North American centres. For the efficacy analyses an intent-to-treat sample was defined. The global efficacy of the two drugs was assessed by the Hamilton Depression scale (HAM-D) and Clinical Global Impression (CGI) scores. Antidepressant activity was also assessed using the percentage of responders on the CGI "improvement" scale. In addition the time of onset of antidepressant effect was evaluated by weekly analysis of individual HAM-D items. The intent-to-treat sample was stratified retrospectively according to the severity of the depression (mild, moderate or severe). Regarding global efficacy, compared with placebo, only fluvoxamine significantly improved the HAM-D total scores at Week 4 (p < 0.05). There was a suggestion from individual HAM-D item scores (depressed mood, suicide, psychic anxiety) that fluvoxamine had an earlier effect than imipramine. Overall, compared with placebo, more HAM-D items were improved by fluvoxamine than imipramine. Fluvoxamine but not imipramine was significantly superior to placebo in severely depressed patients as shown by improvements in the HAM-D score (p < 0.01) and the CGI "improvement" score (p < 0.05). Side effect profiles for the active agents were typical for their pharmacological category:imipramine was associated with anticholinergic effects, particularly dry mouth, and fluvoxamine was associated with nausea and vomiting.

Comparison of compliance between serotonin reuptake inhibitors and tricyclic antidepressants: a meta-analysis

A meta-analysis of 67 published randomized controlled clinical trials comparing selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs), which measured discontinuation rates for side effects and lack of efficacy, was performed. All multiple publications and trials using non-TCA comparators were excluded. Ten studies were placebo controlled; these were analysed separately. Overall, the difference in withdrawals due to side effects of SSRIs and TCAs was -4.5% (p = 0.0004) and that due to lack of efficacy was 0.1% (p = 0.86). In the placebo-controlled trials the differences between the two groups were -7.9% and -0.1% (p = 0.06 and 0.96), respectively. These results demonstrate that SSRIs have a significant and clinically important advantage over TCAs with respect to tolerability, whereas efficacy is similar. Treatment failure due to poor compliance can increase health-care costs: therefore, in selecting an antidepressant for the first-line treatment of major depressive disorders, the risks, benefits and costs of each type of treatment need to be critically evaluated.

Long-term treatment of depression

Long-term treatment of depression encompasses two separate phases: relapse and recurrence prevention. Relapse prevention aims to consolidate the response to acute treatment. Some tricyclic antidepressants (TCAs) have been shown to be effective, possibly in lower than standard acute treatment doses. The selective serotonin reuptake inhibitors (SSRIs) have been shown to be effective at the same minimum effective doses used to treat acute depression, or in a lower dose as with citalopram. Recurrence prevention aims to reduce the risk of onset of a new episode of depression in patients with recurrent depression. Imipramine has been thoroughly studied in unipolar depressed patients in full therapeutic doses for up to five years and is clearly effective. Other TCAs have not been adequately tested and may not all be equally effective. The SSRIs fluoxetine, paroxetine and sertraline have also been shown to be effective in reducing the risk of new episodes of depression.

Neuroendocrine responses to intravenous L-tryptophan in obsessive compulsive disorder

We studied the neuroendocrine responses produced by intravenous L-tryptophan (TRP) in 16 untreated patients with obsessive compulsive disorder (OCD) and 16 matched healthy controls. The increase in plasma growth hormone seen following TRP was significantly greater in the OCD patients, while TRP-induced prolactin release did not differ from controls. Taken in conjunction with findings from other neuroendocrine studies the data suggest that some aspects of 5-HT1A neurotransmission may be increased in OCD. This increase may represent a compensatory change which promotes adaptation to stress in non-depressed OCD patients.

The optimal dosing regimen for citalopram--a meta-analysis of nine placebo-controlled studies

Optimal dosing schedules for an antidepressant drug can only be established during clinical studies in depressed patients. The benefits of antidepressant therapy are usually progressive, and thus patients must be maintained on a particular treatment for at least 3-4 weeks to assess the efficacy of different doses. Meta-analysis, a widely accepted statistical technique which allows the combination of the results of multiple studies, was used to assess the efficacy of several doses of citalopram over nine placebo-controlled clinical trials. Statistically significant differences between citalopram and placebo were found at both the 20 and 40 mg dose levels. The minimal effective dose of citalopram was shown to be 20 mg. However, analysis of patient subgroups revealed a tendency for those patients suffering from severe or recurrent depression to achieve better results with a higher dosage (40 mg), while patients experiencing their first period of depression or with less severe depression responded well to the minimally effective dose of 20 mg.

Placebo-controlled efficacy of antidepressants in continuation treatment

All episodes of depression require treatment after symptomatic response of the acute episode in order to consolidate response. If treatment is discontinued early, 30% to 50% of patients will suffer a relapse of the inadequately treated episode. Placebo-controlled studies with a variety of antidepressants, old and new, have provided compelling evidence of the efficacy of anti-depressants on relapse prevention. A recent study of citalopram has also shown the need for long-term treatment with anti-depressants in patients whose acute episode of depression appeared to respond to placebo since their response was not maintained.

Antidepressants in long-term treatment

One of the most important recent developments in the management of depression is the recognition of the need for long-term treatment. Treatment of an episode of depression must continue after apparent response in order to consolidate response and prevent relapse. A continuation treatment period of at least four months after response of the acute episode is required in all patients with depression. Most depression is recurrent, and prophylactic treatment with antidepressants reduces the risk of new episodes. This treatment needs to be continued over very long periods, because the risk of new episodes does not appear to diminish with time. In selecting an antidepressant for long-term treatment efficacy, safety and tolerability in the long term should be taken into account since not all antidepressants have been adequately tested, and some do not appear to be effective. The most thoroughly tested antidepressants are the tricyclic imipramine and the new selective serotonin reuptake inhibitors.