TORONTO - The maker of the contraceptive device NuvaRing is informing women about new restrictions for the use of the product.
Merck Canada Inc. says the prescription birth control ring should not be used by women who smoke and are over age 35 or who have at least one potentially serious medical condition, including heart disease, high blood pressure, abnormal blood-fat levels, clotting disorders or diabetes.
In a Health Canada advisory Thursday, Merck also said NuvaRing should not be used by women who have had migraine headaches with vision problems or constant stomach pain caused by pancreatic dysfunction along with high levels of fats in the blood.
The flexible ring, which is inserted into the vagina, releases a continuous low dose of estrogen and progestin to prevent ovulation.
The use of such combination hormone contraceptives, including oral formulations, is associated with increased risks of several serious adverse effects, including blood clots, strokes and heart attacks.
Common side-effects related to NuvaRing include: vaginal irritation; headache; mood changes; nausea and vomiting; weight gain; breast discomfort and acne.
But Merck said women using the contraceptive should also be alert to other potential effects, among them joint pain and swelling, unco-ordinated jerking movements, skin blistering, hearing loss, intestinal problems, and swelling around the eyes, face and lips.
"Talk to your doctor right away if you experience any of these problems," the company advises.
NuvaRing, which was approved for use in the U.S. in 2001 and a year later in Canada, has sparked numerous lawsuits involving thousands of women, who have accused the drug maker of selling the contraceptive while knowing it posed a higher risk of life-threatening blood clots than competing birth-control products.