DRESS syndrome: Addressing the drug hypersensitivity syndrome on combination of Sodium Valproate and Olanzapine

Carbamazepine-induced DRESS Syndrome: A Rare Delayed Hypersensitivity Reaction

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is a rare but severe cutaneous drug hypersensitivity reaction. Delays in making a diagnosis of DRESS syndrome and lack of timely treatment may result in morbidity and mortality. However, the presentation can be misinterpreted as other pathologies because of a broad spectrum of clinical presentations, delayed reactions, and prolonged course. Despite the discontinuation of the medication that is the culprit, relapses of drug reactions frequently occur weeks to months later. Several drugs that are associated with DRESS syndrome are prescribed as psychotropic medications. This report describes the case of a patient with DRESS syndrome who was evaluated with the RegiSCAR scoring system as a "definite case," which was possibly induced by carbamazepine prescribed to treat bipolar I disorder. The young female patient was successfully treated with steroid medication after carbamazepine was discontinued. She was prescribed aripiprazole for mood stabilization without a subsequent recurrence of DRESS syndrome. We recommend that, in cases such as described here, clinicians take DRESS syndrome into consideration and provide proper timely management, particularly for patients receiving psychotropic drugs. A brief review of the literature concerning DRESS syndrome associated with psychotropic drugs and its pathogenesis are outlined and discussed.

Association of antipsychotic use with raised eosinophil count

The current study aimed to assess the possibility of an association between first and second generation antipsychotic medication and raised eosinophil count. A total of 22 in-patients at the psychiatric unit of the University General Hospital ‘Attikon’, a tertiary hospital, were included in the present study. Patients had received antipsychotic monotherapy and did not have any co-morbidities or require additional treatments. Patients were monitored weekly and their eosinophil count was assessed. One-way ANOVA and summary measures analysis were applied to study the effect of time and medication type on the absolute eosinophil concentration (or relative percentage) for each patient. The differences in mean eosinophil concentrations or relative percentage by patient and time were also assessed. An increase in the absolute concentration and the relative percentage of eosinophils over time was observed in patients receiving Olanzapine, Haloperidol and Aripiprazole. However, there was no difference between individual medications. In conclusion, antipsychotics may be associated with increased eosinophil count over time; however, larger studies involving more patients and a longer follow-up are required to reach a definitive conclusion.

The Effect of Valproic Acid on Olanzapine Serum Concentration: A Study Including 2791 Patients Treated With Olanzapine Tablets or Long-Acting Injections

BACKGROUND

The combination of olanzapine and valproic acid (VPA) is regularly prescribed in the treatment of bipolar or schizoaffective disorders. The VPA has been shown to reduce olanzapine concentration, but the mechanism behind this interaction remains unknown. We aimed to investigate the effect of VPA on olanzapine concentration during oral versus long-acting injectable (LAI) formulation in a real-life setting.

METHODS

From a therapeutic drug monitoring service, prescribed doses and serum concentrations from 2791 olanzapine-treated patients (9433 measurements) were included.

RESULTS

The number of patients on olanzapine-LAI treatment was 328, whereas 2463 were using oral olanzapine. The frequency of patients comedicated with VPA was 9.4% for olanzapine tablets and 5.8% for olanzapine-LAI. The VPA had no effect on olanzapine dose-adjusted concentrations in LAI users (1.6 vs 1.7 [ng/mL]/[mg/d]; P = 0.38), whereas in the oral group the dose-adjusted olanzapine concentration was lower in VPA users (2.2 vs 2.7 [ng/mL]/[mg/d]; P < 0.001). For smokers in the oral olanzapine group using VPA, 8.7% of the measurements were in the subtherapeutic range (<10 ng/mL) compared with 6.0% in nonusers (P = 0.003).

IMPLICATIONS

These findings show that the VPA-olanzapine interaction involves a presystemic mechanism and is therefore restricted to oral olanzapine treatment. For oral treatment of olanzapine, comedication with VPA implies a risk of insufficient effect, which may be of clinical relevance in smokers in particular. Thus, it is important to be aware of the interaction potential with VPA during oral olanzapine use, whereas for LAI-treated patients fewer precautions are required from a pharmacokinetic point of view.

A Rare Presentation of Clozapine-Induced DRESS Syndrome

Drug reaction with eosinophilia and systemic symptoms (DRESS syndrome) is an uncommon side effect of certain medications. It causes a skin reaction, with eosinophilia and other organ involvement. This case describes a presentation of a 32-year-old female with a past medical history significant for schizophrenia and bipolar disorder who presented for a rash. She had been started on clozapine 10 days prior to admission. After extensive workup she was found to have DRESS syndrome secondary to clozapine use. This is the second reported case in the literature of clozapine-induced DRESS syndrome. This case is unique because it is the first case to present with the common manifestations of DRESS syndrome including eosinophilia, rash, lymphadenopathy, and organ involvement after clozapine use.