Felbamate relieves several abnormal pain sensations in rats with an experimental peripheral neuropathy.
The antiepileptic drug, felbamate, was tested in a rat model of painful peripheral neuropathy (the chronic constriction injury model). Intraperitoneal doses of 150, 300 and 600 mg/kg were given to animals with established heat-hyperalgesia, mechanohyperalgesia, mechano-allodynia and signs of spontaneous pain (hindpaw guarding). Postinjection tests were conducted 2, 6, 12, 24 and 48 h later. The 150 mg/kg dose had little or no effect on any measure. Significant reductions in all measures of abnormal pain were seen after the 300 and 600 mg/kg doses; relief lasted 2 to 12 h. Side effects were trivial or absent by 2 h postinjection. Felbamate's actions were generally antihyperalgesic and antiallodynic, rather than analgesic, in that the responsiveness of the control (sham-operated) hindpaw was unaffected. We conclude that felbamate suppresses neuropathic pain sensations and that its effectiveness may be due to multiple mechanisms of action. The recently discovered severe side-effect liability of felbamate is likely to preclude its clinical application.
Imamura
Y
Y
Neurobiology and Anesthesiology Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland, USA.
Bennett
G J
GJ
D000700:Analgesics / Q000009:adverse effects / Q000494:pharmacology*; D000818:Animals; D000927:Anticonvulsants / Q000009:adverse effects / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D000078328:Felbamate; D006361:Heating; D006614:Hindlimb / Q000187:drug effects / Q000294:innervation; D006930:Hyperalgesia; D008297:Male; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement / Q000187:drug effects; D010523:Peripheral Nervous System Diseases / Q000150:complications / Q000188:drug therapy*; D048448:Phenylcarbamates; D011409:Propylene Glycols / Q000009:adverse effects / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000700:Analgesics; D000927:Anticonvulsants; D048448:Phenylcarbamates; D011409:Propylene Glycols; D000078328:Felbamate