Differential sensitivities to risperidone and olanzapine in a human immunodeficiency virus patient

Abstract

Background: Neuroleptic sensitivity presents a considerable problem for the treatment of psychosis in the acquired immunodeficiency syndrome (AIDS) and human immunodeficiency virus (HIV)-positive patient population. As yet, there are few data on the response of these patients to newer atypical antipsychotic medications.

Methods: We present the detailed medication history of a 33-year-old man with AIDS, who had a prior history of extrapyramidal symptoms (EPS) with both typical antipsychotics and risperidone, and was treated with olanzapine for major depression with psychotic features.

Results: The patient developed akathisia in a dose-dependent manner at dosages between 10 and 15 mg daily of olanzapine, but no EPS. Akathisia responded to dose reduction and use of β-adrenergic blockade.

Conclusions: The AIDS patient may exhibit sensitivity even to newer atypical antipsychotics. The lack of EPS and response to a β-blocker underscore the different mechanisms causing akathisia and EPS.

Introduction

Sensitivity to dopamine-blocking agents among patients with human immunodeficiency virus (HIV) and the acquired immunodeficiency syndrome (AIDS) has been well described in recent literature Ayuso 1994, Hriso et al 1991, Sewell et al 1994a. Basal ganglia involvement as a sequela of HIV infection is one postulated mechanism for such sensitivity Berger et al 1994, Factor et al 1994, Wiley et al 1996. Subcortical involvement is seen in patients with HIV-1-associated cognitive/motor disorder, who typically present with extrapyramidal manifestations including psychomotor slowing and tremor (Dana Consortium on Therapy for HIV Dementia and Related Cognitive Disorders 1996). While antipsychotic sensitivity appears worse when cognitive decline supervenes, it has been noted among patients with new-onset psychosis during an asymptomatic period of HIV infection Sewell et al 1994a, Sewell et al 1994b.

Clozapine was the first atypical antipsychotic available, but possessed numerous side effects and a risk of agranulocytosis that effectively prevented usage with HIV patients (Baldessarini and Frankenberg 1991). Nevertheless, it remained the only alternative to typical antipsychotics for treatment of psychosis until the release of risperidone in 1994, and olanzapine in 1996. Lacking the risk of agranulocytosis, these atypical antipsychotics could be utilized in HIV patients. Both compounds exhibit in vitro and positron-emission tomography (PET) binding profiles characteristic of atypical antipsychotics: low dopamine D₂ receptor occupancy, and high levels of postsynaptic serotonin (5-HT)₂ blockade Farde et al 1995, Nordstrom et al 1993a, Nordstrom et al 1993b, Nyberg et al 1997. Favorable results with both agents have in part been ascribed to their lower propensity for causing extrapyramidal side effects (EPS) Arnt 1995, Chouinard et al 1993, Klieser et al 1995, Tollefson et al 1997, Tollefson and Sanger 1997. Thus, one might predict better tolerability of atypical antipsychotics in HIV patients. In a published series of 21 patients with HIV-related psychosis treated with risperidone, the authors reported drowsiness in 3 patients and drooling in 2 as the only adverse events (Singh et al 1997).