Gabapentin may be hazardous in myasthenia gravis.
A patient with painful neuropathy developed ocular, facial, and masticatory weakness and fatigue after 3 months of gabapentin (GBP) treatment (400 mg/day). An elevated level of serum acetylcholine receptor antibodies (AChR-Ab) was detected. The patient recovered following pyridostigmine therapy and withdrawal of GBP and, 2 years later, is practically asymptomatic despite positive AChR-Ab. Because of this clinical observation, we gave 150 mg/kg GBP to rats with experimental autoimmune myasthenia gravis (EAMG). Repetitive nerve stimulation at 3-Hz was performed, and the 5th/1st amplitude ratio was used to calculate the decremental response. In all EAMG rats, GBP induced a transient, abnormal decrement (7-20%) 90 to 240 min after administration. No decrement was induced by GBP in normal rats. Thus, GBP aggravates the decrement in EAMG. The mechanism involved in the hitherto unreported possible unmasking of myasthenia gravis (MG) by GBP is unknown. Gabapentin should be used with caution in this disease.
Department of Neurology, Hadassah University Hospital, Jerusalem Israel.
N
N
Boneva
T
T
Brenner
Z
Z
Argov
D000085:Acetates / Q000009:adverse effects*; D000200:Action Potentials / Q000187:drug effects; D000368:Aged; D000588:Amines; D000818:Animals; D000927:Anticonvulsants / Q000009:adverse effects*; D001323:Autoantibodies / Q000097:blood; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage; D000075202:Contraindications; D003509:Cyclohexanecarboxylic Acids; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D000077206:Gabapentin; D006801:Humans; D009157:Myasthenia Gravis / Q000139:chemically induced* / Q000188:drug therapy / Q000276:immunology; D011729:Pyridostigmine Bromide / Q000008:administration & dosage; D051381:Rats; D011917:Rats, Inbred Lew; D011950:Receptors, Cholinergic / Q000276:immunology; D005680:gamma-Aminobutyric Acid
D000085:Acetates; D000588:Amines; D000927:Anticonvulsants; D001323:Autoantibodies; D002800:Cholinesterase Inhibitors; D003509:Cyclohexanecarboxylic Acids; D011950:Receptors, Cholinergic; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D011729:Pyridostigmine Bromide