Medicine & Research

Fampridine SR - One Step Closer to Becoming a Reality

By Ellen Guthrie Whipple, Pharm.D.

Muscle weakness and gait (walking) disturbances plague many patients with multiple sclerosis. Very soon, a new drug – with the generic name of Fampridine SR – will become commercially available to help people with MS who suffer from these two common and challenging symptoms. Various studies that examined the effectiveness of Fampridine SR in patients with MS showed, when compared to placebo, treatment with Fampridine SR led to improvements in both walking speed and in the strength of leg muscles. Once released, the brand name of this product manufactured by Acorda Therapeutics is expected to be Ampriva®.

According to Ben W. Thrower, M.D., director of the MS Institute at Shepherd Center and Senior Medical Advisor to the MSF, “Many people in the MS world, including both patients and clinicians, are really excited about the impending release of Fampridine SR. While far from a cure for MS, Fampridine SR offers hope for individuals who have problems walking due to MS.” Dr. Thrower went on to explain that Fampridine SR is the first product approved by the U.S. Food and Drug Administration to treat MS-related gait disturbances.

How does Fampridine SR work?

Fampridine SR is classified as a selective neuronal potassium channel blocker. Exactly how Fampridine SR improves mobility in MS patients is unknown. It has been proposed that Fampridine SR improves conduction in nerve fibers in which myelin has been damaged and that this improves mobility.

What is Fampridine SR used to treat?

Initially, Fampridine SR will only be approved to treat people with MS who suffer from gait disturbances. However, it is also being studied as a treatment for gait disturbances in people who have suffered a spinal cord injury as well as a treatment of fatigue and heat sensitivity in patients with MS.

Is Fampridine SR the same as 4-Aminopyridine?

Fampridine SR contains the same active ingredient as 4-aminopyridine (or 4AP), a medication that MS patients have been purchasing from compounding pharmacies for many years. Fampridine SR differs from 4-aminopyridine in how it is released in the body. Because Fampridine SR is a sustained-release product (hence the SR in the name) it has an increased duration of effect and does not have to be dosed as often as compounded 4-aminopyridine.

How should Fampridine SR be taken?

It is very important to take Fampridine SR exactly as directed by your doctor. Most people will be prescribed the medication twice per day. The first dose should be taken first thing in the morning and the second dose should be taken in the early afternoon. If you forget to take a dose, take the missed dose as soon as possible unless it is almost time for the next dose. Never take two doses at the same time. Fampridine SR can be taken with or without food. It is very important to swallow the capsule whole. It should never be crushed or chewed. 

Are there any special instructions regarding taking Fampridine SR?

This product should not be taken by women who are pregnant, nursing, or trying to get pregnant; or in people who have epilepsy or who have kidney problems.

What are the common adverse effects associated with Fampridine SR?

• Drowsiness, lightheadedness, and dizziness are very common; therefore, people should be careful driving a car or using dangerous machinery

• Numbness and tingling in the face or hands

• Stomach problems (nausea, vomiting, constipation, or abdominal pain) can occur; when stomach problems occur try taking the medicine with food or milk

• Restlessness

• Anxiety

• Headache

When should I call my doctor?

If Fampridine SR causes severe confusion or agitation, you should notify your doctor. If you have a seizure while taking Fampridine SR, you should stop taking the medicine and also notify your doctor as soon as possible.

Ellen Guthrie received her doctorate of pharmacy degree from the University of Georgia College of Pharmacy in 1994 and has been a medical advisor with the MSF since 2002.  She is an assistant clinical professor at the University of Georgia College of Pharmacy, where she lectures primarily on MS.  She practices pharmacy at Children’s Healthcare of Atlanta, where she is a pediatric pharmacist.  She is a member of the American Pharmaceutical Association, the Atlanta Academy of Institutional Pharmacists, and the Consortium of MS Centers.

 (Last reviewed 2/2010)