Comparative evaluation of olanzapine efficacy in the maintenance treatment of bipolar disorder

Olanzapine is superior to lamotrigine in the prevention of bipolar depression: a naturalistic observational study

BACKGROUND

Bipolar disorder is a highly recurrent disease and has great impact on the function of patients. Depressive symptoms consist of more than 50% of life time during the illness and may lead to self harm or suicidal behaviors. Little is known about the antidepressant effects of olanzapine, an atypical antipsychotic, as monotherapy despite its indication for preventing manic episodes. In contrast, lamotrigine, a mood stabilizer, has been proven to be effective in preventing depression in patients with bipolar disorder. However, no studies have compared the efficacy between lamotrigine and olanzapine in the maintenance treatment of bipolar disorder. This enriched naturalistic study was implemented to assess the effectiveness of olanzapine and lamotrigine as monotherapy in the prevention of recurrence of bipolar disorder.

METHODS

Patients with bipolar disorder in a euthymic state (Young's Mania Rating Scale (YMRS) score <12, and 21-item Hamilton Depression Rating Scale (HAM-D) score <7) for at least two months, having already received either olanzapine or lamotrigine as the maintenance treatment were recruited. The patients maintained with olanzapine (n = 22) were applied to olanzapine group whereas those maintained with lamotrigine (n = 29) were applied to lamotrigine group. They were followed up for 12 months. Differences in the efficacy between olanzapine and lamotrigine in recurrence prevention were analyzed. The Kaplan-Meier method was used to generate time-to-recurrence curves, and differences between the two groups were compared using the log-rank test.

RESULTS

Olanzapine had a significantly lower recurrence rate of depressive episodes than lamotrigine (20.0% vs. 57.7%, χ2 = 6.62, p = .010). However, olanzapine and lamotrigine had similar mania (15.0% vs. 0%, χ2 = 4.17, p = .075, Fisher's exact test) and any mood episode (35.0% vs. 57.7%, χ2 = 2.33, p = .127) recurrence rates. Olanzapine was significantly superior to lamotrigine in the time to recurrence of depressive episodes (χ2 = 4.55, df = 1, p = .033), but there was no difference in the time to recurrence of any mood episode (χ2 = 1.68, df = 1, p = .195).

CONCLUSIONS

This prospective naturalistic study suggests that olanzapine is more effective than lamotrigine in the prevention of depressive episodes in patients with bipolar disorder. Future large-scale randomized studies are warranted to validate our results.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT01864551.

Valproic acid, valproate and divalproex in the maintenance treatment of bipolar disorder

BACKGROUND

Bipolar disorder is a recurrent illness that is amongst the top 30 causes of disability worldwide and is associated with significant healthcare costs. In the past, emphasis was placed solely on the treatment of acute episodes of bipolar disorder; recently, the importance of episode prevention and of minimisation of iatrogenicity has been recognised. For many years, lithium was the only mood stabiliser in common use, and it remains an agent of first choice in the preventative treatment of bipolar disorder. However, an estimated 20% to 40% of patients may not respond adequately to lithium. Valproate is an anticonvulsant drug that has been shown to be effective in acute mania and is frequently used in maintenance treatment of bipolar disorder. When the acceptability of long-term treatment is considered, together with efficacy, the adverse event profile of a medication is also important. This is an update of a Cochrane review first published in 2001 and last updated in 2009.

OBJECTIVES

1. To determine the efficacy of valproate continuation and maintenance treatment:a) in preventing or attenuating manic, depressive and mixed episodes of bipolar disorder;b) in preventing or attenuating episodes of bipolar disorder in patients with rapid cycling disorder; and; c) in improving patients' general health and social functioning, as measured by global clinical impression, employment and marital stability.2. To review the acceptability to patients of long-term valproate treatment, as measured by numbers of dropouts and reasons for dropping out, by compliance and by reference to patients' expressed views regarding treatment.3. To investigate the adverse effects of valproate treatment (including general prevalence of side effects) and overall mortality rates.

SEARCH METHODS

Search of the Cochrane Register of Controlled Trials and the Cochrane Depression, Anxiety and Neurosis Group Register (CCDANCTR) (to January 2013), which includes relevant randomised controlled trials from the following bibliographic databases: The Cochrane Library (all years), EMBASE, (1974 to date), MEDLINE (1950 to date) and PsycINFO (1967 to date). No language restrictions were applied. Reference lists of relevant papers and previous systematic reviews were handsearched. Pharmaceutical companies marketing valproate and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating participants with bipolar disorder to long-term treatment with valproate or any other mood stabiliser, or antipsychotic drugs, or placebo. Maintenance treatment was defined as treatment instituted specifically or mainly to prevent further episodes of illness.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data. A double-entry procedure was employed by two review authors. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy, acceptability and tolerability. For dichotomous data, risk ratios were calculated with 95% confidence intervals (CIs). For statistically significant results, we calculated the number needed to treat for an additional beneficial outcome (NNTB) and the number needed to treat for an additional harmful outcome (NNTH). For continuous data, mean differences (MDs) or standardised mean differences (SMDs) were calculated along with 95% CIs. MDs were used when the same scale was used to measure an outcome; SMDs were employed when different scales were used to measure the same outcome. The primary analysis used a fixed-effect model. Binary outcomes were calculated on a strict intention-to-treat (ITT) basis; dropouts were included in this analysis. When data were missing and the method of "last observation carried forward" (LOCF) had been used to do an ITT analysis, then the LOCF data were used.

MAIN RESULTS

Six randomised controlled trials (overall 876 participants) lasting 6 to 24 months were included. Two studies (overall 312 participants) compared valproate with placebo, four studies (overall 618 participants) valproate with lithium, one study (overall 23 participants) valproate with olanzapine and one study (overall 220 participants) valproate with the combination of valproate plus lithium. In terms of study quality, most studies reported the methods used to generate random sequence; however, only one study reported enough details on allocation concealment. Four of six included studies described their design as "double blind", but only two trials reported full details about blinding. Valproate was more effective than placebo in preventing study withdrawal due to any mood episode (RR 0.68, 95% CI 0.49 to 0.93; NNTB 8), but no difference in efficacy was found between valproate and lithium (RR 1.02, 95% CI 0.87 to 1.20). Valproate was associated with fewer participants dropping out of treatment for any cause when compared with placebo or lithium (RR 0.82, 95% CI 0.71 to 0.95 and RR 0.87, 95% CI 0.77 to 0.98, respectively). However, combination therapy with lithium plus valproate was more likely to prevent relapse than was monotherapy with valproate (RR 0.78, 95% CI 0.63 to 0.96). Significant differences in adverse event frequencies were found, and lithium was associated with more frequent diarrhoea, polyuria, increased thirst and enuresis, whereas valproate was associated with increased sedation and infection.

AUTHORS' CONCLUSIONS

Limited evidence supports the efficacy of valproate in the long-term treatment of bipolar disorder. Clinicians and patients should consider acceptability and tolerability profile when choosing between lithium and valproate-their combination or other agents-as long-term treatment for bipolar disorder.

Olanzapine in the long-term treatment of bipolar disorder: a systematic review and meta-analysis

Olanzapine was licensed in the USA by the Food and Drug Administration in 2003 for the prevention of relapse in patients with bipolar disorder when the acute manic episode had responded to treatment with olanzapine. However, olanzapine is commonly used in clinical practice for preventing relapse in patients with bipolar disorder even when acute response has not been demonstrated. The aim of this systematic review and meta-analysis is to determine the effectiveness and acceptability of olanzapine in preventing recurrent mood episodes in bipolar disorder. MEDLINE, EMBASE, the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled up to July 2008 were accessed. Only randomised controlled trials comparing olanzapine with placebo or other active drugs for long-term treatment were included. Two reviewers independently extracted data. Authors were contacted to provide additional data. Of the five trials included in this review, four were conducted by Eli Lilly, the manufacturer of olanzapine. Olanzapine was more effective than placebo at preventing manic relapse, but there was no difference between olanzapine (alone or in combination with lithium or valproate) and placebo (alone or in combination with lithium or valproate) in terms of relapse into any mood episode, as defined as primary outcome by authors in each of the primary studies. We conclude that olanzapine may prevent further manic episodes only in patients who have responded to olanzapine in an acute manic or mixed episode and who have not previously had a satisfactory response to lithium or valproate.

Pharmacological interventions for the prevention of relapse in bipolar disorder: a systematic review of controlled trials

We conducted a systematic review and meta-analysis of randomised and quasi-randomised controlled trials evaluating all clinically relevant pharmacological interventions for the prevention of relapse in people with bipolar disorder. Thirty-four trials were included in the review. Direct comparisons with placebo and with lithium were available for most drugs. In addition, there were direct comparisons of valproate vs. olanzapine, imipramine vs. lithium plus imipramine, olanzapine plus mood stabilisers vs. mood stabilisers and perphenazine plus mood stabilisers vs. mood stabilisers. Methodological quality varied across studies and the strength of evidence was not equal for all treatments or for all comparisons. There is evidence from placebo-controlled trials for the efficacy of lithium, valproate and lamotrigine as maintenance therapy for the prevention of relapse in bipolar disorder. Three drugs have a significant effect in the prevention of manic relapses (lithium, olanzapine and aripiprazole) and three in the prevention of depressive symptoms (valproate, lamotrigine and imipramine). Imipramine is little used in practice, because of concern about adverse effects. The significant effects of olanzapine and aripiprazole were demonstrated in selected responsive bipolar I patients only. Despite widespread use in clinical practice, there is little evidence to support the efficacy of combination therapy.

Olanzapine in long-term treatment for bipolar disorder

BACKGROUND

Many patients with bipolar disorder require long-term treatment to prevent recurrence. Antipsychotic drugs are often used to treat acute manic episodes. It is important to clarify whether olanzapine could have a role in long-term prevention of manic and depressive relapses.

OBJECTIVES

To assess the effects of olanzapine, as monotherapy or adjunctive treatment, in preventing manic, depressive and mixed episodes in patients with bipolar affective disorder.

SEARCH STRATEGY

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (September 2006), the Cochrane Central Register of Controlled Trials (September 2006), MEDLINE (1966-December 2007), EMBASE (1980-2006), CINAHL (1982-2006), PsycINFO (1872-2006) and reference lists. We also contacted experts, trialists and pharmaceutical companies in the field.

SELECTION CRITERIA

Randomised controlled trials comparing olanzapine with placebo or other active treatment in long-term treatment of bipolar disorder.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Five trials (1165 participants) were included in the review. There was no statistically significant difference between olanzapine and placebo (either alone or in combination with lithium or valproate) in terms of number of participants who experienced relapse into mood episode (random effects RR 0.68, 95% CI 0.43 to 1.07, p = 0.09; 2 studies, n=460), however restricting the analysis to the trial that compared olanzapine monotherapy versus placebo, there was a statistically significant difference in favour of olanzapine (RR 0.58, 95% CI 0.49 to 0.69, p<0.00001). No statistically significant difference was found between olanzapine and other mood stabilisers (lithium or valproate) in preventing symptomatic relapse for any mood episode, however, olanzapine was more effective than lithium in preventing symptomatic manic relapse (RR 0.59, 95% CI 0.39 to 0.89, p = 0.01; 1 study, n=361). Olanzapine either alone or as adjunctive treatment to mood stabilisers was associated with significantly greater weight gain than placebo. By contrast, olanzapine was associated with a lower rate of manic worsening, but with a higher rate of weight increase and depression than lithium.

AUTHORS' CONCLUSIONS

Though based on a limited amount of information, there is evidence that olanzapine may prevent further mood episodes in patients who have responded to olanzapine during an index manic or mixed episode and who have not previously had a satisfactory response to lithium or valproate. However, notwithstanding these positive results, the current evidence is stronger for lithium as first line maintenance treatment of bipolar disorder.

Quetiapine and classical mood stabilizers in the long-term treatment of Bipolar Disorder: a 4-year follow-up naturalistic study

BACKGROUND

The aim of this naturalistic study was to compare the effectiveness of quetiapine and classical mood stabilizers, as mono- or combination therapy, in the long-term treatment of Bipolar Disorder (BD).

METHODS

232 DSM-IV BD I (n=91) or BD II (n=141) patients, treated and followed up for four years, were studied. Mood stabilizers were chosen by the treating psychiatrists on the basis of their clinical judgement. The sample was subdivided into 6 treatment groups: quetiapine (n=41), lithium (n=39), sodium valproate (n=73), lamotrigine (n=31), quetiapine plus lithium (n=25), and quetiapine plus sodium valproate (n=23). Throughout the 4-year follow-up period patients were assessed monthly, or whenever a recurrence occurred, by the administration of HAMD-21 and of the YMRS. Primary outcome measures were the duration of euthymia and the cumulative proportion of subjects who maintained euthymia. Kaplan-Meier survival analyses were done to tabulate and compare the differences in survival distributions across the different treatment groups (Log-Rank Mantel-Cox test).

RESULTS

The combined treatments with quetiapine plus lithium or sodium valproate were more effective overall in maintaining euthymia, (percentages of patients who maintained euthymia: 29.3% for quetiapine, 46.2% for lithium, 32.9% for sodium valproate, 41.9% lamotrigine, 80% for quetiapine plus lithium, and 78.3% for quetiapine plus sodium valproate). In addition, quetiapine monotherapy was as effective as lithium monotherapy or combination treatment with lithium or sodium valproate in preventing the recurrence of major depressive episodes.

LIMITATION

The main limitations of the study are the lack of randomized, controlled conditions and the low doses of quetiapine used.

CONCLUSION

If the results from this study will be replicated, there will be important implications for the use of quetiapine in the long-term treatment of BD.

Why do physicians switch from one antipsychotic agent to another? The "physician drug stereotype"

There is a lack of research on why physicians select a certain drug in an individual case and not another available alternative, although this drug selection process is important for quality assurance and cost control. Four hundred ninety-five psychiatrists documented in a standardized form patient and illness characteristics of 1711 schizophrenic outpatients who were switched for individual clinical reasons from an ongoing neuroleptic treatment to olanzapine, and of another 1654 schizophrenic outpatients whose present neuroleptic medication was continued. Physicians also filled in the "Reason for Treatment Selection Questionnaire." Patients who were switched to olanzapine were more ill and showed more preexisting extrapyramidal symptoms and less patient compliance. Reasons of psychiatrists to switch to olanzapine were the expectation of better efficacy and tolerability of the present treatment and patient preferences to continue with the present medication. The price of olanzapine is seen as a reason not to select olanzapine but has no effect on the treatment decision. The "physician drug stereotype" of olanzapine corresponds with clinical data on the efficacy and tolerability of olanzapine. The data show that medical decisions about drug selection are multidimensional, integrating knowledge about the clinical properties of the drug, personal experiences and information about the individual case. The Reason for Treatment Selection Questionnaire is an instrument that allows to objectively assess important aspects of medical decision making, to generate psychological drug profile, and to understand why physicians prefer one drug over alternatives.

The use of atypical antipsychotics beyond psychoses: efficacy of quetiapine in bipolar disorder

BACKGROUND AND RATIONALE

Atypical antpsychotics have been sucessfully used in the treatment of bipolar disorder (BD), either as adjunctive or as monotherapy. Quetiapine is an atypical antipsychotic extensively used in the treatment of psychotic disorders. It has serotonergic and dopaminergic activity and it appears to be selective for the mesolimbic and mesocortical dopamine system. The aim of this paper was to review the recent literature on the use of quetiapine in the treatment of BD.

METHODS

The literature databases currently available online were searched for papers on quetiapine and BD. Papers and reports published between January 1995 and June 2005 were selected and reviewed critically.

RESULTS

Augmentative low dose quetiapine was found to be effective in BD partially responsive to conventional mood-stabilizers. Manic and mixed episodes have been the best studied, and quetiapine was found to be effective either as monotherapy or as adjunctive therapy in both randomized clinical trials and open-label studies. Data on the use of quetiapine in bipolar depression showed a significant efficacy and high remission rates. Maintenance data suggested a role of quetiapine as a good alternative to classical mood stabilizers in reducing recurrence rates of BD. A few studies on the efficacy in rapid cycling BD have also been published.

CONCLUSIONS

Quetiapine is an effective agent for the short- and long-term treatment of BD. The mechanism of action of quetiapine as a mood stabilizer is still unknown. Some preliminary data suggest the involvement of glutamate pathways but further studies are needed to clarify this issue.