Health Canada is warning that the antibiotic Avelox may be linked to rare but dangerous liver problems.
The drug regulator says Bayer Inc., which makes the drug, is updating the product label to draw attention to this potential side-effect.
Avelox is used to treat a broad spectrum of bacterial infections, including respiratory illnesses.
But concerns raised in recent years in a variety of jurisdictions led Health Canada to investigate whether people taking the drug are at increased risk of liver injury.
Health Canada says anyone who develops certain symptoms while on Avelox should stop taking the drug and contact their health care professional immediately.
The symptoms are: abdominal pain, loss of appetite, yellowing of the skin and eyes, severe itching, dark urine, and pale-coloured stools.
The generic name of the drug is moxifloxacin; it is in the quinolone class of antibiotics.
Bayer updated the labelling for Avelox in Europe in the summer of 2007 and sent a "Dear Doctor" letter to European physicians to draw attention to the change in early 2008.
That move followed a review of the safety data for the drug by the European Medicines Agency's Committee for Medical Products for Human Use.