Cetirizine: an antihistamine associated with dystonia and oculogyric crises.

Madam, cetirizine hydrochloride, an antihistamine, is the active constituent of Zyrtec® that functions as competitive peripheral H1 receptor inhibitor.1 Cetirizine is known to have reduced blood-brain barrier penetration due to its larger mass, lipophobic properties and increased attraction for peripheral H1 receptors. Oculogyric crisis is a neurologic impairment defined by bilateral dystonic, commonly upward, conjugate eye movements. Various drugs including cefixime, olanzapine and metoclopramide have been associated with this adverse complication.