January 2008 Safety labeling updates & new warnings: mycophenolic acid (Myfortic), varenicline (Chantix), and desmopressin

Key Points

The boxed warning for mycophenolic acid (Myfortic, Novartis) delayed-release tablets has been updated to change the pregnancy category from C to D. The update includes information regarding the increased risks of miscarriage and congenital malformation when the agent is used during the first trimester of pregnancy.

FDA has asked healthcare providers to monitor patients taking varenicline (Chantix, Pfizer) for behavioral and mood changes, including suicidal thoughts and aggressive and erratic behavior. Patients should use caution while driving or operating machinery as drowsiness has also been reported in patients treated with varenicline.

FDA has requested that the label for desmopressin (DDAVP Nasal Spray, DDAVP Rhinal Tube, DDAVP, DDVP, Minirin, and Stimate Nasal Spray) be updated to include information regarding the risk of severe hyponatremia and seizures that can result in death with use of the agent. Intranasal formulations of desmopressin should no longer be used to treat primary nocturnal enuresis (PNE) and should not be used to treat patients with hyponatremia or with a history of hyponatremia. Treatment of PNE with desmopressin tablets should be interrupted if a patient has an acute illness that could lead to fluid and/or electrolyte imbalance. Caution should be used with all formulations of desmopressin when treating patients at risk for water intoxication with hyponatremia.