Health Canada is warning doctors and consumers that the drug Sensipar should not be used by people under the age of 18.
The advice follows word of the death of an American teenager who was taking the drug as part of a clinical trial.
Sensipar is used to treat disorders of the parathyroid gland that result in high levels of calcium in the blood.
The drug has been approved for use by adults in Canada and the U.S. and the company that makes it, Amgen, was testing Sensipar to see if it was safe and effective when used by children.
A 14-year-old in the trial developed very low blood calcium levels and died; it's not clear if the drug caused the condition.
Health Canada says it has received no reports of adverse reactions to Sensipar involving patients under the age of 18.
The clinical trials were being conducted in the U.S. and all those involving people 18 or younger have been stopped. There are no clinical trials of Sensipar in children in Canada, the department says.
Health Canada says the drug's packaging already warns that taking Sensipar might result in low blood calcium levels. But it says it is reviewing the safety information and may update the drug's labelling.
Symptoms of hypocalcemia — low blood calcium — include convulsions, irregular heartbeat, involuntary contraction of muscles and numbness in the hands, feet, mouth and lips. Health Canada says health-care professionals should carefully monitor patients for these symptoms.