In developed countries, Guillain-Barre Syndrome (GBS) is the most common cause of acute
neuromuscular paralysis, afflicting about 5,000 persons annually in the United States. Over
20% of GBS patients have permanent residual motor deficits that affect their activities of
The goal of this study is to assess the potential usefulness and safety of 4-aminopyridine
(4-AP) in those patients who suffer chronic functional deficits from GBS.This medication is
a potassium channel blocker that has the potential to improve nerve conduction, particularly
across partially demyelinated axons. It is felt that by increasing nerve conduction there
will be improved motor performance for walking and activities of daily living, as well as
decreased fatiguability. This medication has demonstrated potential usefulness in central
demyelinating diseases such as multiple sclerosis.Because the peripheral nervous system is
much more accessible to systemic medication delivery it is felt that this medication may
improve the functional status of those patients who are suffering from the residual side
effects of this medication.
Objective.- To determine the safety and efficacy of orally delivered 4-aminopyridine for
motor weakness due to Guillain-Barre Syndrome (GBS) under a FDA approved protocol (IND No:
Setting.- Tertiary care outpatient rehabilitation center directly attached to a university
Subjects.- Subjects who are unable to ambulate more than 200 feet without assistive devices
and have residual nonprogressive motor weakness due to GBS more than one year out from the
Design.- Subjects will be randomized to a double-blind, placebo-controlled, cross-over
design, which had two eight-week treatment arms with a three-week washout. The average
dosage at 4 weeks will be 30 milligrams (mg) per day.
Patients who demonstrate improvement will be continued on the medication for an additional
three months. Assessments will be performed every two weeks during the randomized trial and
every month for those continued for up to three months on the medication.
- Male or Female, 19 to 75 years of age, irrespective of race.
- Subject is able to and has voluntarily given informed consent prior to the
performance of any study specific procedures.
- Subject has neurological impairment secondary to GBS, which has been stable for more
than 12 months.
- Subject has motor strength that averages less than 5.0 but greater than 3.0 on the
ASIA motor scale.
- Subject is able and willing to comply with protocol.
- Subjects will agree to no change in their outpatient therapy, or home exercise
programs during enrollment in the study.