Hypotension and Bradycardia in a Healthy Volunteer following a Single 5 mg Dose of Olanzapine

Olanzapine is an atypical antipsychotic medication indicated for the treatment of schizophrenia and other manifestations of psychotic illness. Common side effects include somnolence, constipation, weight gain, and postural hypotension. The authors report a case of hypotension accompanied by bradycardia in a normal, healthy volunteer participating in an olanzapine pharmacokinetic study following a single 5 mg dose. A venous catheter allowed for serial blood sampling of olanzapine concentrations before, during, and after the adverse event. The subject experienced a rapid absorption of the drug and higher than anticipated maximum plasma concentrations. This case suggests that atypical antipsychotics, although generally better tolerated than conventional agents, may still result in untoward reactions that may be partially due to individual differences in drug absorption and metabolism.