Novartis Pharmaceuticals Canada Inc. said its drug Gilenya (fingolimod) causes the heart rate to slow down in the first hours after ingestion, but it returns to normal after about a month of treatment.
Gilenya can also cause an irregular heartbeat, especially after the first dose, Novartis said in a Health Canada advisory Thursday.
Isolated cases of adverse effects on the heart, including temporary but serious irregularity in heart beat and one case of unexplained death, have also been observed within 24 hours of the first pill, possibly associated with Gilenya, the advisory said.
A number of Canadians have reported heart-related side-effects, most of which occurred within six hours of taking the first dose of Gilenya.
No deaths definitively attributed to Gilenya have been reported in Canada. There have been a number of international reports of deaths in patients being treated with the drug, some of which were considered possibly linked to the medication.
In the updated product monograph for the drug, Novartis said patients starting treatment with Gilenya or resuming treatment after a break are now required to have an electrocardiogram (ECG) before starting the drug and six hours after taking the first dose.
Patients must also stay at the clinic or doctor's office for at least six hours after taking the initial pill to have hourly heart-rate and blood-pressure checks.
Gilenya is prescribed to treat the relapsing-remitting form of MS, and is generally recommended for patients who have not responded well to or cannot tolerate one or more of the other therapies.