Summary
The central effects of single oral doses of phenobarbitone and phenytoin have been determined in six normal volunteers by measuring the critical flicker fusion threshold (CFF) under double-blind, placebo controlled conditions at intervals of up to 7 h after ingestion of the drug. Blood samples were taken at the same time for estimation of the serum concentration of the drugs by gas chromatography. Phenobarbitone in a dose of 180 mg produced a significant fall in CFF, and the time-course of this change mirrored the time-course of the serum concentration of the drug, which reached a peak of 21.8 µM (5.2 µg/ml) at 1.5 h. Phenytoin in doses of 200 mg, 300 mg and 400 mg produced no significant change in CFF even though an adequate serum concentration of the drug had been achieved (28.8 µM, 7.2 µg/ml, with the 400 mg dose). It was concluded that the two drugs differ in their action on the neural mechanisms tested by this procedure.
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Houghton, G.W., Latham, A.N. & Richens, A. Difference in the central actions of phenytoin and phenobarbitone in man, measured by critical flicker fusion threshold. Eur J Clin Pharmacol 6, 57–60 (1973). https://doi.org/10.1007/BF00561802
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DOI: https://doi.org/10.1007/BF00561802