4-Aminopyridine (also known as 4-AP and Fampridine) is a drug that blocks the potassium channels in neurons. This effectively improves the transmission of nerve impulses down damaged axons. It does not replace damaged myelin but users of 4-aminopyridine report dramatic improvement in a number of symptoms especially paraesthesia. It should be born in mind that this is an experimental drug and the side-effects are uncertain. Dosages should be carefully regulated as potassium is a chemical that is used extensively in other parts of the body including heart functions. It is currently been investigate for MS patients. We make a 10mg capsules with a slow release matrix.