Epilepsy drugs increase older adults' risk for bone fractures, a new study shows.

Canadian researchers analyzed the medical records of 15,792 people 50 and older who'd had non-traumatic fractures between April 1996 and March 2004. Each person was matched with up to three people who'd never had a fracture, for a total of 47,289 people to serve as controls.

The researchers also looked at the participants' use of epilepsy drugs, including carbamazepine (Carbatrol, Epitol, Tegretol), clonazepam (Klonopin), ethosuximide (Zarontin), gabapentin (Gabarone, Neurontin), phenobarbital (Luminal), phenytoin (Dilantin, Phenytek) and valproic acid (Depakene, Depakote).

All but one of the drugs was associated with an increased risk for fractures. The greatest risk was among people taking phenytoin and carbamazepine. Valproic acid was the only drug not linked with an increased chance of fractures.

The results, published in the January issue of Archives of Neurology, were similar for people taking just one epilepsy drug and those taking more than one.

"In conclusion, our study showed that most anti-epileptic drugs except for valproic acid are associated with an increased likelihood of non-traumatic fracture in individuals aged 50 year or older," wrote Dr. Nathalie Jette, of the University of Calgary's Foothill Hospital, and colleagues in a journal news release.

They called for further research into the effects of epilepsy drugs on bone health.

There's encouraging news for women with epilepsy who want to nurse their babies. Children whose mothers took certain anti-seizure medications while breast-feeding don't appear to suffer any negative cognitive effects by age 3, a new study finds.

The multi-center study looked at nearly 200 children whose mothers took one of four common antiepileptic drugs, and found no difference in IQ levels at age 3 among those who were breast-fed versus formula-fed.

"For women who have epilepsy, this is one less thing that they as new mothers have to worry about," said lead author Dr. Kimford Meador, a professor of neurology at Emory University in Atlanta. The study was published in the Nov. 24 online edition and in the Nov. 30 print issue of the journal Neurology.

The findings are part of the Neurodevelopmental Effects of Antiepileptic Drugs study, an ongoing trial looking at the long-term cognitive effects on children whose mothers took one of four common antiepilepsy meds during and after their pregnancies: carbamazepine (Carbatrol, Equetro, Tegretol, Tegretol XR), lamotrigine (Lamictal), phenytoin (Dilantin, Phenytek) or valproate (Depakote, Depakote ER, Depakene).

For the study, Meador and his colleagues examined the results of IQ tests given to 199 three-year-olds whose mothers entered the trial while they were still pregnant. A total of 194 women at 25 epilepsy centers were enrolled in the study from 1999 to 2004, and there were five sets of twins.

Forty-two percent of the babies were breast-fed, for an average of six months, and mothers who breast-fed tended to have higher average IQs than those who didn't (104 versus 95). After controlling for the mother's IQ, the researchers found that the average IQ in the breast-fed group of children was 99, versus 98 in the non-breast-fed group.

The new study on breast-feeding comes after other research suggesting hazards to the developing fetus from exposure to one anti-seizure medication. Last year, the researchers reported that babies who were exposed to the drug valproate in utero had IQs at age 3 that were an average of 9 points lower than babies whose mothers took one of the other three drugs during pregnancy. They also found that the effect was dose-dependant, meaning the higher the dose of valproate, the lower the IQ. Other studies have shown that exposure to valproate during the first trimester can increase the risk of birth defects.

Meador speculated that one reason there was no difference in IQ levels among breast-fed and formula-fed babies exposed to valproate may be because "the level of the drug in the infants' bloodstreams was very much lower than it was during pregnancy."

Dr. Autumn Klein is director of the Program in Women's Neurology at Brigham and Women's Hospital in Boston, and the author of an editorial accompanying the study. She said the study "provides the most information thus far" when it comes to counseling women who take antiepilepsy drugs on the risks of breast-feeding.

Klein believes the findings "will definitely change" people's attitudes toward the use of these drugs during breast-feeding. Right now, she said, many doctors do not recommend breast-feeding for women taking the medications "due to the largely unknown effects of [antiepilepsy drugs] during breast-feeding."

Dr. Jacqueline French, a professor of neurology at New York University School of Medicine who treats many women with epilepsy, said the findings were reassuring in that, "even if a drug produces problems in utero, it doesn't produce additional problems for the baby during breast-feeding," she said.

French said another possibility for the difference seen in valproate exposure in utero versus during breast-feeding may be that "the brain is developing incredibly rapidly in utero, and so that may be a very sensitive time for exposure to valproate."

Meador cautioned that the results were preliminary and that additional studies covering a wider range of antiepilepsy drugs are needed.

"We studied the four most commonly used drugs in our epilepsy centers during the time the women were enrolled," he said. "We're now hoping to get additional funding to go and look at other drugs."

The study was funded by the U.S. National Institutes of Health and the U.K. Epilepsy Research Foundation.