hydroxyzine and prolonged QTc

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 hydroxyzine and inc QTC europe 2015​ in dropbox, or http://www.ema.europa.eu/docs/en_GB/document_library/Press_release/2015/02/WC500182462.pdf ). 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.

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