Intrauterine Drug Research Articles

Withdrawal symptoms consisting of severe tremors, irritability, opisthotonos and increased muscle tonus were observed in two siblings born to a mother requiring mephobarbital for control of seizures. Both infants manifested symptoms within the first minutes of life and continued to be symptomatic for 2-6 months after delivery. At birth the infants were small for gestation and had some of the physical findings (Hill, et al) observed in infants exposed to intrauterine anticonvulsant drugs. Somatic growth during the first 4 years and 18 months of life, respectively, was normal but mental development in the second infant at 18 months of age was slow (D.Q. 83). Placental transfer of mephobarbital was documented in both infants by selective ion detection using a gas chromatograph-mass spectrometer-computer system. Prolonged excretion of mephobarbital and phenobarbital was demonstrated in the second infant. At the time of delivery the maternal urine contained 17.22 μg/ml of phenobarbital and 1.15 μg/ml of mephobarbital. Urine collected from the infant between 10-27 hours of age contained 13.15 μg/ml of phenobarbital and .88 μg/ml of mephobarbital. Subsequent samples examined on 5, 8, 10, 15 and 22 days of age revealed continued excretion of phenobarbital (.13 μg/ml) through the last sampling period.

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