Randomized Study of L-Baclofen in Patients With Refractory Trigeminal Neuralgia

PROTOCOL OUTLINE: This is a randomized, double blind, placebo controlled, parallel study.

Patients are randomized to receive either L-baclofen or placebo orally at increasing daily
doses for 1 week. Patients then continue to receive the maximum dosage acceptable for a 1
week maintenance period.

Patients, thereafter, may enroll in a long term open label study with L-baclofen.

Patients are followed at 1, 3, 6, 9, and 12 months.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics-- Idiopathic trigeminal neuralgia - Paroxysmal attacks of facial
or frontal pain lasting a few seconds to less than 2 minutes - Pain has at least 4 of the
following characteristics: Distribution along one or more divisions of the trigeminal
nerve Sudden, intense, sharp, superficial, stabbing, or burning quality Pain intensity
severe Precipitation from trigger areas, or by certain daily activities such as eating,
talking, washing the face, or cleaning the teeth Between paroxysms entirely asymptomatic -
No neurological deficit - Attacks are stereotyped in the individual patient - Exclusion of
other causes of facial pain by history, physical examination and special investigations
when necessary Must be uncontrolled or refractory as defined by occurrence of at least 2
paroxysms of pain per day despite conventional treatment with maximally tolerated doses of
carbamazepine --Prior/Concurrent Therapy-- No concurrent medication for trigeminal
neuralgia other than carbamazepine, phenytoin, and neurontin Concurrent medication for
other conditions allowed Concurrent medication must be on stable dose(s) --Patient
Characteristics-- Hepatic: No significant hepatic disease Renal: No significant renal
disease Neurological: No evidence of progressing neurological disorder (e.g., intracranial
neoplasm, multiple sclerosis) Other: No history of drug abuse Not pregnant Effective
contraception required of all fertile patients