Cetirizine – how much is too much?

Abstract Background Cetirizine hydrochloride is a commonly used over‐the‐counter antihistamine that may be prescribed in larger doses than are commonly used for allergic rhinitis for the management of chronic urticaria. Aim To describe a case report of a paediatric patient who was treated with long‐term and high‐dose cetirizine. Clinical details The patient developed a dystonic reaction probably as a result of the antihistamine overuse. The child involved in this case was taking the maximum daily dose regularly for several years. Outcomes The parent was advised to cease treatment with (high dose and prolonged use) cetirizine and substitute a lower intermittent dose of an alternative antihistamine. Conclusion Although cetirizine is widely considered a ‘safe’ medication, prescribers and pharmacists should be mindful that it has the potential to cause unacceptable side effects.