Health Canada has placed restrictions on Allergan's uterine fibroid treatment Esmya, after discovering a possible link between its use and the risk of a rare but serious liver injury.
The regulator has announced that the drug, sold under brand name Fibristal in the country, should not be used by women with liver problems, or by those who have had liver problems in the past.
It also stated that more than one treatment course of the drug should be restricted to only those of childbearing age, who are unable to undergo surgery to remove the fibroids.
The drug has also been rejected by the US Food and Drug Administration (FDA), requesting more information and citing safety issues outside the United States.
Europe has also recommended restrictions on use of the drug for some patients to help minimise risks, despite Hungarian drugmaker Richter - the supplier in Europe - claiming Esmya to be a safe and effective form of treatment.
Esmya is a medicine used to treat moderate to severe symptoms of uterine fibroids in adult women who have not yet reached the menopause. Uterine fibroids are non-cancerous (benign) tumours of the womb (uterus).
The treatment is commonly given as a single course in women before they have surgery for their fibroids, and as intermittent treatment for women in whom surgery is not suitable.