Phenytoin Pregnancy and Breast Feeding Warnings
Phenytoin is also known as: Di-Phen, Dilantin, Phenytek, Phenytoin Sodium, Prompt
Overview
Phenytoin Suspension may cause harm to the fetus. If you think you may be pregnant, contact your doctor. You will need to discuss the benefits and risks of using Phenytoin Suspension while you are pregnant. Phenytoin Suspension is found in breast milk. Do not breast-feed while taking Phenytoin Suspension.
Phenytoin Pregnancy Warnings
Phenytoin has not been formally assigned to a pregnancy category. An increased risk of congenital malformations has been associated with the use of anticonvulsants agents (including phenytoin) in epileptic women during pregnancy. Anomalies associated with anticonvulsant use in pregnancy include neural tube defects, cleft lips, cleft palates, cardiac defects, and microcephaly. A specific "fetal hydantoin syndrome" involving a number of abnormalities has been described. Neonatal coagulation defects have also been reported in infants whose mothers took phenytoin during pregnancy. Vitamin K administered to the mother before delivery and to the neonate has been reported to reduce this defect. Phenytoin may cause folate deficiency. Some clinicians have recommended early maternal monitoring of folate levels and administration of folic acid when appropriate. There are no controlled data in human pregnancy. Phenytoin should only be given during pregnancy when there are no alternatives and benefit outweighs risk.
Features of the fetal hydantoin syndrome include both craniofacial and distal limb abnormalities. The specific facial features include a broad nasal bridge, wide fontanel, epicanthic folds, short upturned nose, hypertelorism, ocular abnormalities, prominent and low set ears, wide mouth, cleft lip or palate, prominent lips and variations in the size and shape of the head. The specific distal limb abnormalities include hypoplasia of the distal phalanges, finger-like thumbs, small or absent nails, and altered palmar creases. A variety of tumors (including neuroblastoma) have also been reported in the offspring of women taking phenytoin. Recent studies have suggested that in utero exposure to phenytoin may result in significantly lower IQ scores. Some clinicians have recommended that the need for anticonvulsant therapy be reevaluated prior to pregnancy if possible. If a need is clearly present, consideration may be given to the use of alternative anticonvulsants (such as carbamazepine) which may pose a smaller risk. If phenytoin therapy is deemed necessary, close observation for clinical and laboratory evidence of altered phenytoin effect is indicated throughout the course of pregnancy. Pregnancy results in a number of changes in the pharmacokinetic disposition of phenytoin. The plasma clearance is increased (with a peak just before or in the first weeks after delivery). The plasma protein binding is decreased. Some of the changes in the pharmacokinetic disposition of phenytoin may be related to increases in the hepatic metabolism of the drug. Some women who must take phenytoin during pregnancy may require dose increases in order to maintain seizure control. Physicians are encouraged to register patients before fetal outcome is known (e.g., ultrasound, results of amniocentesis, etc) into the Antiepileptic Drug (AED) Pregnancy Registry at 1-888-233-2334 or 1-888-AED-AED4. This is an ongoing study at the Massachusetts General Hospital/Harvard Medical School. This study is designed to monitor the outcomes of pregnant women exposed to antiepileptic drugs in order to determine which therapies are associated with increased risk.
Phenytoin Lactation Warnings
Phenytoin is excreted into human milk in small amounts. Typical doses given to a nursing mother would be expected to result in very small infant doses (less than 5% of a typical dose for most infants). The American Academy of Pediatrics classifies phenytoin as a drug which is "usually compatible with breast-feeding." The Academy notes one case of methemoglobinemia as a cause of possible concern.
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