Effect of Thioridazine on Phenytoin Serum Concentration: A Retrospective Study
1987 ◽
Vol 21
(3)
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pp. 267-272
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Keyword(s):
The Mean
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Serum Phenytoin concentrations before and after the addition of thioridazine were retrospectively compared in 27 adults to determine if an interaction occurred between these two drugs. A change in the serum phenytoin concentration of ± 4 μg/ml was considered clinically significant; by this definition four patients (14.8 percent) had an increase, two (7.4 percent) had a decrease, and most (77.8 percent) demonstrated no change. The mean difference was 0.8 μg/ml ± 3.7 μg/ml and was not found to be statistically significant (p < 0.1). Clinically important alterations in phenytoin serum concentration as caused by thioridazine appear to be infrequent.