Bad for the Bones

Researchers study effects of individual anti-epileptic drugs on bone health

(RxWiki News) Past studies have established links between anti-epileptic drugs and bone density loss. Now, new research indicates that specific anti-epileptic drugs correspond to an increased risk of bone fractures in people 50 years of age and older.

The findings are published in the January issue of the journal Archives of Neurology.

Epilepsy and osteoporosis are common conditions in elderly people. In the United States, over 300,000 people older than 65 years of age have epilepsy. According to estimates by the National Osteoporosis Foundation, about 12 million people over 50 years of age have osteoporosis. As both diseases are highly prevalent in older adults, it is important to study the effects of individual drugs on bone health.

Nathalie Jetté, M.D., M.Sc., from the University of Calgary, Foothills Hospital, and colleagues conducted such drug-specific research. The researchers examined the medical records of 15,792 patients who suffered non-traumatic fractures between April 1996 and March 2004. Each patient was compared to as many as three controls (people without a history of fracture).

Jetté and colleagues studied the fracture risks associated with the anti-epileptic drugs carbamazepine, clonazepam, ethosuximide, gabapentin, phenobarbital, phenytoin, and valproic acid. Other anti-epileptic drugs that are prescribed less frequently were classified together as "other anti-epileptic drugs."

The researchers found that patients who take phenytoin are at the greatest risk of fractures. The next highest risk is posed by carbamazepine followed by the group called "other anti-epileptic drugs", next was phenobarbital, then gabapentin, and lastly clonazepam. The research team found no increased risk of fracture associated with valproic acid. They also found that those in polytherapy (taking more than one anti-epileptic drug) are at the greatest risk of fracture.

According to the study's authors, future studies of anti-epileptic drugs should examine the individual effects of specific drugs on patients who are new to those drugs.

Review Date: 
January 11, 2011