NEUROPROTECTION BY DEXTROMETHORPHAN IN ACUTE EXPERIMENTAL SUBDURAL-HEMATOMA IN THE RAT

Experimental acute subdural hematoma in the rat has been shown to prod uce a zone of apparent infarction under the clot, and excitatory amino acid toxicity appears to play a role in the damage observed, We repor t the effect of dextromethorphan, a commonly used antitussive and a no ncompetitive NMDA-type glutamate receptor antagonist, an the volume of histologic damage seen at 72 h after acute subdural hematoma in the r at, Sixty-five Long-Evans rats underwent placement of acute subdural h ematoma using the ''cranial window'' model, Fourteen animals received oral dextromethorphan, 10 mg/kg/dose, twice daily for 3 days, and an a dditional 20 animals also received a single 20 mg/kg intraperitoneal d ose 15 min after clot placement in addition to the oral regimen, Contr ol animals received equal volumes of sterile water. Brain lesions in a il animals were characterized by well-circumscribed infarctions underl ying the subdural hematoma, Lesion volume in control animals was 88.3 +/- 9.3 mm(3) (mean +/- standard error of the mean), while animals rec eiving dextromethorphan had significantly smaller lesions, which was i ndependent of dosing schedule (59.9 +/- 9.2 mm(3))(p = 0.0403), Animal weight was also found to be a significant covariate (p = 0.038), Beca use of its safety in humans and efficacy as a neuroprotectant in a var iety of models, dextromethorphan may be a promising agent for clinical use, particularly in children.