Chronic effects of phenytoin on brain-stem auditory evoked potentials in man.
The effects of phenytoin (PHT) on brain-stem auditory evoked potentials (BAEPs) were studied in 65 epileptic patients who received long-term PHT monotherapy at therapeutic and supra-therapeutic levels with no clinical evidence of brain-stem toxicity. Abnormal BAEPs were found in 7.5% and 33.3% of patients with therapeutic and supra-therapeutic PHT levels respectively. Serum PHT levels had a trend towards a positive relationship with the I-V interpeak latency (IPL), and a significant negative relationship with the amplitudes of waves I and V. At supra-therapeutic levels, both I-V and I-III IPLs were significantly prolonged while at therapeutic levels only I-III IPLs were prolonged. The absolute latency of wave I was prolonged in both the therapeutic and the supra-therapeutic groups. These results suggest that PHT acts both peripherally on either the auditory nerve or the cochlea, and centrally on brain-stem conduction.
Chan
Y W
YW
University Department of Medicine, Queen Mary Hospital, Hong Kong.
Woo
E
E
Yu
Y L
YL
D000293:Adolescent; D000328:Adult; D001933:Brain Stem / Q000187:drug effects*; D004828:Epilepsies, Partial / Q000188:drug therapy / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D006801:Humans; D008297:Male; D010672:Phenytoin / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use*; D012044:Regression Analysis
D010672:Phenytoin