Two Medicines Added to TdP Conditional Risk List

Hydroxyzine and metoclopramide were added to the list of drugs that cause Torsades de Pointes (TdP) under certain clinical conditions.

Hydroxyzine (marketed as Atarax®, Vistaril® and many other brand names) is an antihistamine that is used to treat allergies, anxiety and other conditions.  It has been added to the list of drugs with Conditional Risk of TdP because it is associated with TdP in patients with conditions such as low serum potassium or magnesium, extremely slow heart rate or concomitant use of drugs known to cause TdP and/or prolong the QT interval.

Metoclopramide (marketed as Reglan® and many other brand names) is an anti-emetic that is used to treat nausea, vomiting and other conditions.  It has been added to the list of drugs with Conditional Risk of TdP because it is associated with TdP in patients with conditions such as concomitant use of drugs known to cause TdP and/or prolong the QT interval.

Hydroxyzine and metoclopramide have also been added to the list of Drugs to be Avoided by Patients with Congenital Long QT Syndrome (CLQTS) if at all possible.