Heart rhythm drug Multaq may cause liver injury, according to its manufacturer, Sanofi-Aventis Canada Inc.

The Canadian Press reports that the maker of the drug, which is used to treat an abnormal heart rhythm, issued a warning Tuesday about the potential for liver injury in patients taking the medication.

Sanofi-Aventis Canada Inc., working in collaboration with Health Canada, said there have been reports of liver dysfunction in some patients treated with Multaq, which is taken to control the heart-rhythm condition atrial fibrillation.

Dronedarone hydrochloride, which is marketed under the trade name Multaq, was licensed in 2009 and is used to prevent recurrence of atrial fibrillation and treat arrhythmias.

Patients taking Multaq should immediately report to their doctors any symptoms suggestive of liver injury, including loss of appetite, nausea, vomiting, unusual fatigue, right upper stomach area pain or discomfort, yellowing of the skin or whites of the eyes (jaundice), unusual darkening of the urine, or itching.

Patients should consider obtaining periodic liver function tests, the company advised.

Cases of serious liver injury or other serious or unexpected side-effects in patients taking Multaq should be reported to Health Canada via its website healthcanada.gc.ca/medeffect, or by calling 1-866-234-2345.