The first drug approved by the Food and Drug Administration to reduce the risk of stroke from blood clots in both women and men will be available soon, according to a company that holds its U.S. rights.
Syntex Corp. announced yesterday in New York that the drug, sold as Ticlid, will go on the market by Dec. 16.
Stroke is the nation's third leading cause of death after heart disease and cancer, killing about 150,000 people a year.
Ticlid was described as "a significant advance" by Dr. Thomas R. Price, a neurologist who directs the Stroke Center at the University of Maryland Medical Center.
"No medication before Ticlid was proven or approved to reduce the risk of stroke in women," he said.
Price was one of many researchers who participated in a study conducted at 56 medical centers in the United States in the 1980s that compared Ticlid with aspirin. It showed Ticlid, or ticlopidine hydrochloride, was 48 percent more effective than aspirin at reducing the risk of initial stroke during the first year of treatment -- the year of greatest danger.
Aspirin has been the only medication approved by the FDA for reducing stroke risk. But aspirin has limitations, such as the inability of some patients to tolerate it.
Furthermore, previous stroke studies failed to establish aspirin's benefits for women.
Introduced in France in 1978, Ticlid is available in 45 other countries.
Ticlid belongs to a class of drugs known as platelet aggregation inhibitors. A chemical called adenosine diphosphate (ADP) is the go-between common to many stimuli that cause platelets (disk-shaped blood cells) to bind into a mass that forms an obstructing blood clot that can break away and lead to stroke. Ticlid interferes with the formation of this blood clot and other mechanisms that activate ADP.
In the study comparing Ticlid with aspirin, the risk reduction for fatal or non-fatal stroke was 36 percent for women who had experienced a stroke warning sign, such as transient weakness on one side of the body, slurring of speech, or fleeting loss of vision in one eye.
Price said Ticlid should be prescribed only if the patient has experienced a stroke warning sign and is allergic to aspirin or aspirin is not indicated. The recommended Ticlid dosage is two pills, which cost $3.
The most serious side effect of Ticlid is neutropenia, a condition in which a component of white blood cells is reduced. The condition can lead to death, Price warned.