Multiple Sclerosis Probably the most common problems people who suffer from Multiple Sclerosis (MS) face on a daily basis are weakness and fatigue.  Also, many patients are faced with visual problems and with cognitive or concentration effects.  Very few of the treatments available have much effect on these situations.  However, clinical research has shown that many patients can benefit from a little-known medication known as 4-Aminopyridine.  This research, which began in 1984, includes the results of a long-term safety and effectiveness study published in The Archives of Neurology Journal in 1994.  What is 4-Aminopyridine? 4-Aminopyridine (4-AP) is known as a "potassium channel blocker". This means that it can block the flow of potassium ions in nerve cells, which results in a more effective nerve impulse traveling down toward the muscles. As you probably know, the poor nerve impulses in patients with MS is the cause of most of the symptoms of the disease.  The improved nerve conduction provided by the 4-AP means that the muscles have a "louder signal" to tell them when to work.  Thus, stronger muscle contractions improve strength and fatigue in many patients.  However, for reasons not fully understood, the 4-AP does not work in all patients.  One study referred to above indicates that 75% of patients with MS report a significant clinical response, and that 80% to 90% of these people will benefit from long-term adminstration of the medication.  Other studies report a lower response rate, around 30% to 50%.  A related compound, 3-4 diaminopyridine, is used in another neurological disease known as Lambert-Eaton Syndrome.  It is not commonly used in Multiple Sclerosis. Why has my doctor not told me of this option?  4-AP is not a patentable medication, since it was discovered many years before its effects on MS were known.  Many doctors are aware of its existence, but are not aware that it is available.  The medication is available as the raw ingredient, and a compounding pharmacy can put it into capsules based on the dosage determined by weight of the patient and the response to 4-AP.  Some doctors prefer to use an immediate release capsule exclusively, while others will change their patients to a sustained release form after a person's correct dosage is determined.  The sustained release form offers more convenient dosing, and can minimize any possible side effects.  Seizures, which usually occur? Patients report that side effects are usually minor, and include paresthesias (usually tingling sensations around the face) and occasional stomach problems.  The most serious side effect is seizures, which usually a dosage-related problem but can occur at any dosage.  For this reason, the dosage is tailored to each individual and the person's maximum dose should never be exceeded.  How do I get 4-Aminopyridine?  At this time, 4-Aminopyridine is available only from a compounding pharmacy. It does require a doctor's prescription, so please feel free to have your doctor call us to discuss the medication, or show him this information.  We have copies of the full article from the Archive of Neurology Journal and others, and would be happy to send him or her a copy of it.  If you have any questions please feel free to use the "Ask the Pharmacist" option for a response via email.