| |
|
4-AMINOPYRIDINE (4-AP)
Clinical Neuropharmacology, Vol. 16, pp. 195-204
4-Aminopyridine (4-AP) is a drug shown to improve visual function and motor
skills and relieve fatigue in patients with Multiple Sclerosis (MS). 4-AP is most effective
in patients with the chronic progressive form of MS, in patients who are temperature
sensitive, and in patients who have had ms for longer than three years. Common side effects
include dizziness, nervousness and nausea, and the incidence of adverse effects was shown
to be less than 5% in all studies.
4-AP works as a potassium channel blocker. Electrophysiologic studies of demyelinated
axons show that abnormal potassium currents decrease action potential duration and
amplitude and contribute to conduction failure. Potassium channel blockade prolongs
the repolarization phase of the action potential, increasing conductivity along the
demyelinated axon.
MS patients treated with 4-AP exhibited a response rate of 29.5% to 80%. A long-term
study (32 months) indicated that 80-90% of patients who initially responded to 4-AP
exhibited long-term benefits. Although improving symptoms, 4-AP does not inhibit
progression of MS.
Spinal cord injury patients have also seen improvement with 4-AP therapy. These
improvements include sensory, motor and pulmonary function, with a decrease in
spasticity and pain.
|
|
|
|
