Diaminopyridine Treatment of Neurological Disorders

The drug 3, 4 diaminopyridine (DAP) is a potassium channel blocker, closely related to 4-aminopyridine. Like 4-AP, DAP blocks the voltage-sensitive potassium channel. However, unlike 4-AP, DAP does not cross the blood brain barrier unless the barrier is broken. DAP therefore should be well suited for treating peripheral demyelination and have less central nervous system mediated side-effects. Many clinical studies of DAP suggest that DAP effectively relieves the symptoms of LambertEaton myasthenia syndrome (LEMS). However, DAP has limited or questionable efficacy for other conditions such as botulinum toxin poisoning, Guillian-Barre, polyneuropathy, myasthenia gravis, and multiple sclerosis, or botulinum toxicity. There is little published data regarding the efficacy of DAP on brain or spinal cord injury. The side-effects of DAP appears to be similar to 4-AP except that it causes more peripheral symptoms. Several cases of seizures have been reported, as well as one incident of cardiac arrest. Otherwise, the drug appears to be well-tolerated in all the clinical trials to date. This article reviews some of the medical literature relating to the use of DAP to treat various neurological disorders.