Ampyra Seizure Side Effects Often Occur Within Days, Weeks: FDA

Multiple Sclerosis patients may face an increased risk of seizures for their first several weeks taking the drug Ampyra, federal health officials warned this week.

In a Drug Safety Communication issued by the FDA on July 23, updated information was provided for the public and medical community about the potential Ampyra seizure side effects, which often occur within days or weeks after starting the recommended dose and occur even among individuals who have no prior history of seizures.

While Ampyra is contraindicated for patients who have a history of seizures, the FDA found that the seizures occurred even in patients without a history of seizures.

Ampyra (dalfampridine) is a drug by Acorda Therapeutics used to improve the walking speed of MS patients. It was already known that there was an overall increased risk of seizures, but data on when the seizures are most likely to occur is new. There is a higher risk of seizures in patients with impaired kidney function, which allows the drug to build up to higher levels in the blood.

The FDA is now reminding health care providers not to give the drug to patients with a history of seizures or impaired kidney functions. The agency also recommended that doctors warn patients against taking a double dose if they missed a dose and recommended patients be taken off Ampyra if they began suffering seizures.

Patients are being encouraged to tell their health care providers if they have kidney problems and not to crush, chew or dissolve Ampyra tablets, which should only be taken whole.

Doctors are also being advised to periodically order blood tests for patients to check kidney function, especially after the age of 50, when mild kidney impairment becomes common.

The label for Ampyra will be updated with the FDA’s new data and recommendations, the agency announced.

The FDA first approved Ampyra in January 2010. But a report from the fourth quarter of that year by the Institute for Safe Medication Practices (ISMP) (pdf) found 217 adverse event reports sent in to the FDA in that three month period which included reports that Ampyra actually decreased walking speed.