The European Medicines Agency (EMA) is warning practitioners that the first-generation antihistamine hydroxyzine (Atarax, Vistaril) is associated with an increase in torsades de pointes (TdP) and QT interval prolongation, which may lead to ventricular fibrillation.

After reviewing the safety of hydroxyzine, EMA’s Pharmacovigilance Risk Assessment Committee (PRAC) recommended the following:

• Hydroxyzine should be prescribed at the lowest effective doses for the shortest possible times.
• Hydroxyzine must not be used by patients who have known risk factors for heart arrhythmias or who are taking drugs that increase the risk for QT prolongation.
• The maximum daily dose should not exceed 100 mg in adults and 2 mg/kg of body weight in children weighing up to 40 kg.
• Hydroxyzine is not recommended for the elderly, but if clinicians believe that its use is unavoidable, the maximum daily dose for this age group should be limited to 50 mg.

The PRAC approved hydroxyzine use for the treatment of anxiety disorders, sleep disorders, pruritus and for use as a pre-operative medication. The FDA has issued similar approvals, and the drug is also used off-label in the U.S. as an antiemetic/antinausea agent for adults.

Limit Hydroxyzine Use to Reduce Cardiac Risks, EU Regulators Say. Medscape. February 13, 2015