A Simplified Phenytoin Regimen for Preeclampsia

The objective of this study was to assess the feasibility of giving phenytoin to a group of mild preeclamptic women in a universal dosing scheme comparable to that typical of magnesium sulfate administration. Serum phenytoin levels were measured at regular intervals for 32 hours following a 1 g intravenous loading dose in 14 patients. A second group of 14 women received 500 mg orally to supplement the 1 g initial dose and had serum levels similarly measured. The resultant serum levels are described, and the effect of maternal weight analyzed. The average serum phenytoin level in the first 14 women given the 1 g loading dose fell to 10 μg/mL approximately 12 hours after treatment. Serum levels plateaued above this threshold in the 14 women given 500 mg of additional medication orally 10 hours after treatment initiation and were maintained for an additional 14 hours before decline was observed. The serum levels resulting from the initial 1 g loading dose were analyzed 8 hours after treatment initiation in the entire group of 28 women according to body weight, and a clinically significant effect of weight on serum level was observed only at the extremes of weight. We conclude that a universal dosing scheme comparable to that typically used for magnesium sulfate is feasible for phenytoin administration to preeclamptic women.