To the Editor: Aripiprazole is a second-generation antipsychotic approved for the treatment of schizophrenia and increasingly used in bipolar patients. It acts as a partial agonist at dopamine receptors and displays high affinity for serotonin 5-HT_1A and 5-HT_2A receptors on 5-HT neurons, producing partial agonism and antagonism, respectively. Its side effects include insomnia, anxiety, headaches, nausea, vomiting, and somnolence (1). Aripiprazole’s affinity for α₁-adrenergic and muscarinic receptors is low; consequently, cardiovascular adverse effects are rare. Only postural hypotension (without clinical symptoms) has been described in elderly patients (2). However, we report a case of hypertensive crisis triggered by aripiprazole.

A number of case reports have demonstrated that the use of new antipsychotics is associated with arrhythmias, prolonged QTc intervals, and orthostatic hypotension in people lacking cardiovascular disorders (3). In this case, we reported that hypertension abated with discontinuation of aripiprazole and reemerged upon rechallenge. Furthermore, sustained hypertension was blocked by the coadministration of propanolol, a nonselective beta-blocker. This points toward adrenergic hyperactivity as the cause of hypertension. Obviously, individual sensitivity is an important factor, as demonstrated by the lack of cardiovascular effects in a case of aripiprazole overdose (4). Further studies are needed to understand the precise mechanisms involved. This is particularly important because atypical antipsychotics are now commonly prescribed over conventional neuroleptics.