Rifampin - Risperidone and Divalproex Drug-drug Interaction: A Case Report

Rifampin is a potent hepatic cytochrome enzyme inducer, promoting the metabolism of many drugs. Here, we describe a case wherein rifampin-induced drug interactions affected the clinical improvement of a patient on psychiatric drugs for bipolar disorder. He was administered divalproex, risperidone, quetiapine, and clonazepam, along with anti-tuberculosis drugs HERZ, containing 600 mg rifampin. Despite taking 900 mg/day divalproex, his serum valproate levels were below 2 μg/ml, and his manic symptom persisted. Therefore, the antipsychotic risperidone (5 mg) was replaced with olanzapine (20 mg). Following this, his manic symptoms improved rapidly. Rifampin is a potent CYP3A and CYP2D6 inducer and is known to significantly reduce serum risperidone levels. Thus, even a high dose of risperidone did not induce a significant clinical effect, which was observed immediately after replacing with olanzapine. Therefore, drug interactions may have had a significant effect on clinical outcomes. Clinicians should be cognizant of drug interactions when treating psychiatric patients on rifampin therapy. The case has been sufficiently revised to protect the patient's personal information.

Divalproex and its effect on suicide risk in bipolar disorder: A systematic review and meta-analysis of multinational observational studies

BACKGROUND

Divalproex has become the most prevalent mood stabilizer for bipolar disorder. However, little is known its effects in the prevention of suicide in patients with bipolar disorder, and recent FDA announcement indicated an increased risk of suicidality when using anti-epileptic agents such as divalproex. The aim of this study is to investigate the effect of divalproex on suicide risk in patients with bipolar disorder.

METHODS

A search strategy was used for the PubMed, Embase, ProQuest, ScienceDirect, Cochrane Library, ClinicalKey, Web of Science, and ClinicalTrials.gov until June 13th, 2018. Peer-reviewed observationally clinical studies in humans, investigating the association of divalproex and suicidality in patients with bipolar disorder were included. A random-effects meta-analysis was implemented to calculate the relative risk (RR) and 95% confidence intervals (CIs) for suicidality among patients receiving divalproex and those without.

RESULTS

Total 6 studies were included in the final meta-analysis. There was no significant difference in the incidence rates (reported as [RR]; 95% CI) of suicide attempts (0.921; 0.383-2.215) or completed suicides (0.607; 0.180-2.043) between participants receiving divalproex vs. no medication. There was no significant difference in the incidence rates of suicide attempts (0.815; 0.453-1.466) or completed suicides (1.009; 0.410-2.484) between participants receiving divalproex and carbamazepine.

LIMITATIONS

The significantly heterogeneous sample sources and study design amount the included trials.

CONCLUSIONS

Treatment with divalproex did not reduce or increase the incidence of suicide-related events in patients with bipolar disorder.

GERI-BD: A Randomized Double-Blind Controlled Trial of Lithium and Divalproex in the Treatment of Mania in Older Patients With Bipolar Disorder

OBJECTIVE

Clinicians treating older patients with bipolar disorder with mood stabilizers need evidence from age-specific randomized controlled trials. The authors describe findings from a first such study of late-life mania.

METHOD

The authors compared the tolerability and efficacy of lithium carbonate and divalproex in 224 inpatients and outpatients age 60 or older with bipolar I disorder who presented with a manic, hypomanic, or mixed episode. Participants were randomly assigned, under double-blind conditions, to treatment with lithium (target serum concentration, 0.80-0.99 mEq/L) or divalproex (target serum valproate concentration, 80-99 μg/mL) for 9 weeks. Participants with an inadequate response after 3 weeks received open adjunctive risperidone. The authors hypothesized that divalproex would be better tolerated and more efficacious than lithium. Tolerability was assessed based on a measure of sedation and on the proportions of participants achieving target concentrations. Efficacy was assessed with the Young Mania Rating Scale (YMRS).

RESULTS

Attrition rates were similar for lithium and divalproex (14% and 18% at week 3 and 51% and 44% at week 9, respectively). The groups did not differ significantly in sedation. Participants in the lithium group tended to experience more tremor. Similar proportions of participants in the lithium and divalproex groups achieved target concentrations (57% and 56%, respectively). A longitudinal mixed model of improvement (change from baseline in YMRS score) favored lithium (change in score, 3.90; 97.5% CI=1.71, 6.09). Nine-week response rates did not differ significantly between the lithium and divalproex groups (79% and 73%, respectively). The need for adjunctive risperidone was low and similar between groups (17% and 14%, respectively).

CONCLUSIONS

Both lithium and divalproex were adequately tolerated and efficacious; lithium was associated with a greater reduction in mania scores over 9 weeks.

Inflammatory markers and chronic exposure to fluoxetine, divalproex, and placebo in intermittent explosive disorder

Intermittent Explosive Disorder (IED) is a disorder of impulsive aggression affecting 4-7% of the U.S. population during some period of life. In addition to other biological correlates, elevations of plasma inflammatory markers have been reported in IED, compared with control, subjects. In this study we sought to explore if treatment exposure to anti-aggressive agents, compared with placebo, would be associated with a reduction in circulating levels of inflammatory markers. Thirty IED subjects, from a 12-week, double-blind, randomized, placebo-controlled trial of fluoxetine and divalproex, in which both pre- and post-treatment levels of C-Reactive Protein (CRP), interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10 and tumor necrosis factor (TNF)-α were obtained. Efficacy measures included the Overt Aggression Scale-Modified (OAS-M) score for Aggression and for Irritability, rate of Clinical Global Impression of Improvement (CGI-I), and rate of IED Remitters at study completion. As compared to placebo, neither fluoxetine nor divalproex reduced any of the measures of aggression. In addition, levels of CRP and pro- and anti-inflammatory cytokines showed no changes from pre- to post-treatment for any treatment condition. Correlations between pre- and post- treatment plasma CRP/cytokines were substantial (mean r=0.71, r(2)=0.50, p<0.001). Overall, circulating markers of inflammation markers were unaffected by treatment with fluoxetine or divalproex, consistent with the absence of change in measures of impulsive aggression.

Effect of initial ziprasidone dose on treatment outcome of korean patients with acute manic or mixed episodes

OBJECTIVE

We investigated the efficacy and tolerability of ziprasidone combined with divalproex to determine the relationship between the initial dose of ziprasidone and the treatment effect among Korean patients with acute bipolar manic or mixed disorders.

METHODS

This study was a 6-week, open-label, prospective investigation of Korean patients with an acute manic or mixed episode of bipolar disorder. Sixty-five patients were recruited. The patients were categorized based on the initial dose of ziprasidone as follows: low (20-79 mg/day) and standard (80 mg/day). Ziprasidone was given in combination with divalproex in flexible doses, according to the clinical response and tolerability.

RESULTS

The response and remission rates were significantly higher in the standard-dose group than the low-dose group. The combination of ziprasidone and divalproex was well-tolerated and adverse events were mostly mild with no statistically significant increase in body weight.

CONCLUSION

The results of this study showed that a standard starting dose of ziprasidone in combination with divalproex for bipolar disorder is more effective than a low starting dose.

Divalproex for the treatment of posttraumatic stress disorder: a retrospective chart review

Objective. Open label trials of divalproex in the treatment of posttraumatic stress disorder (PTSD) show positive results. The objective of this study was to examine the therapeutic effects of divalproex in a larger naturalistic sample of patients with PTSD. Methods. A retrospective analysis was performed on 325 veteran charts identified through a computerized search of PTSD diagnosis matched with pharmacy records (any form of divalproex). The medication names, doses, labs, and dates (except for the divalproex index visit) were blackened. An investigator blinded to the order of visits and blackened information rated the progress notes preceding and following psychopharmacological intervention with divalproex with the Clinical Global Impression Scale for Improvement (CGI-I). Results. Fifty patients met eligibility criteria. Three were treated with divalproex monotherapy and 47 were treated adjunctively. The improved endpoint CGI-I differed significantly from "no change" (P<0.000001). Twenty-five (50%) were rated as very much or much improved on the CGI-I. Patients treated in primary care had a greater improvement compared to those in the mental health setting (P<0.005). Divalproex dosage and serum valproic acid levels (n=37) were well correlated (r = 0.57, P<0.0005). Conclusion. Divalproex treatment improves the global clinical function of veterans with PTSD. Further controlled study is warranted.