By: Dr. Geoffrey Modest
The Pharmacovigilence Risk Assessment Committee (PRAC) of the European Medicines Agency just issues a warning about hydroxyzine being associated with increased QTc intervals and torsade de pointes (see here). Hydroxyzine is a first-generation antihistamine, commonly used for pruritus, anxiety disorders, sleep disorders and as a premedication before surgery, as well as off-label as an anti-emetic. They felt it was okay to continue using hydoxyzine since the cardiac arrhythmias were most likely to occur in those with risk factors, but they do suggest:
–maximum dose of 100mg/d or 2 mg/kg for kids up to 40 kg. Use lowest effective dose and for shortest time possible
–avoid using in those “at risk of heart rhythm problems” or in those taking other medications that prolong the QTc
–try to avoid using in those taking medications that lower the potassium or slow the heart rate, since these may predispose to arrhythmias.
–try to avoid use in the elderly, but if necessary, only up to 50mg/d
–there was no comment in the warning about the frequency of prolonged QTc, the length of the prolongation, or the frequency of torsades or ventricular tachycardia/fibrillation
So, quite unfortunate. hydroxyzine has been my go-to med for persistent pruritus. However, I will now try to avoid it especially in those on other meds which prolong the QTc, especially azithro/clarithromycin, tricyclics, citalopram, as well as in patients predisposed to arrhythmias. And decreasing the maximum dose in elderly seems appropriate.