The Basics
What is Phenytoin?
Used to control certain type of seizures, and to treat and prevent seizures that may begin during or after surgery to the brain or nervous system.
Brand names for Phenytoin
Dilantin
How Phenytoin is classified
Anticonvulsants
Phenytoin During Pregnancy
Phenytoin pregnancy category
Category N/ANote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Phenytoin while pregnant
N/A
Taking Phenytoin While Breastfeeding
What are recommendations for lactation if you're taking Phenytoin?
Breastfeeding during phenytoin monotherapy does not appear to adversely affect infant growth or development, and breastfed infants had higher IQs and enhanced verbal abilities than nonbreastfed infants at 6 years of age in one study.[1] If phenytoin is required by the mother, it is not necessarily a reason to discontinue breastfeeding. Because of the low levels of phenytoin in breastmilk, amounts ingested by the infant are small and usually cause no difficulties in breastfed infants when used alone except for rare idiosyncratic reactions. Combination therapy with sedating anticonvulsants or psychotropics may result in infant sedation or withdrawal reactions. In one case report, maternal phenytoin dosage requirements decreased as breastfeeding was discontinued.[2]
Maternal / infant drug levels
Breastfeeding during phenytoin monotherapy does not appear to adversely affect infant growth or development, and breastfed infants had higher IQs and enhanced verbal abilities than nonbreastfed infants at 6 years of age in one study.[1] If phenytoin is required by the mother, it is not necessarily a reason to discontinue breastfeeding. Because of the low levels of phenytoin in breastmilk, amounts ingested by the infant are small and usually cause no difficulties in breastfed infants when used alone except for rare idiosyncratic reactions. Combination therapy with sedating anticonvulsants or psychotropics may result in infant sedation or withdrawal reactions. In one case report, maternal phenytoin dosage requirements decreased as breastfeeding was discontinued.[2]
Possible effects of Phenytoin on milk supply
Relevant published information was not found as of the revision date.
Possible alternatives to Phenytoin
None listed
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Meador KJ, Baker GA, Browning N et al. Breastfeeding in children of women taking antiepileptic drugs: Cognitive outcomes at age 6 years. JAMA Pediatr. 2014;168:729-36. PMID: 24934501
2. Puckett JB, Butler WM, McFarland JA. Phenytoin and lactation. Arch Neurol. 1982;39:457-8. Letter. PMID: 7103792
3. Mirkin BL. Diphenylhydantoin: placental transport, fetal localization, neonatal metabolism, and possible teratogenic effects. J Pediatr. 1971;78:329-37. PMID: 5539782
4. Horning MG, Nowlin J, Hickert P et al. Identification of drugs and drug metabolites in breast milk by gas chromatography-mass spectrometry. In: Galli C, Jacini G, Pecile A, eds. Dietary lipids and postnatal development. New York: Raven Press, 1973:257-69.
5. Rane A, Garle M, Borga O et al. Plasma disappearance of transplacentally transferred diphenyl-hydantoin in the newborn studied by mass fragmentography. Clin Pharmacol Ther. 1974;15:39-45. PMID: 4808742
6. Horning MG, Stillwell WG, Nowlin J et al. Identification and quantification of drugs and drug metabolites in human breast milk using GC-MS-COM methods. Mod Probl Pediatr. 1975;15:73-9.
7. Kaneko S, Sato T, Suzuki K. The levels of anticonvulsants in breast milk. Br J Clin Pharmacol. 1979;7:624-7. Letter. PMID: 465285
8. Soderman P, Matheson I. Clonazepam in breast milk. Eur J Pediatr. 1988;147:212-3. Letter. PMID: 3366144
9. Meyer FP, Quednow B, Potrafki A et al. [The perinatal pharmacokinetics of anticonvulsant drugs]. Zentralbl Gynakol. 1988;110:1195-205. PMID: 3239295
10. Shimoyama R, Ohkubo T, Sugawara K et al. Monitoring of phenytoin in human breast milk, maternal plasma and cord blood plasma by solid-phase extraction and liquid chromatography. J Pharm Biomed Anal. 1998;17:867-9. PMID: 9682171
11. Sugawara K, Shimoyama R, Ohkubo T. Determinations of psychotropic drugs and antiepileptic drugs by high-performance liquid chromatography and its monitoring in human breast milk. Hirosaki Med J. 1999;51(Suppl):S81-6.
12. Bar-Oz B, Nulman I, Koren G et al. Anticonvulsants and breastfeeding. A critical review. Paediatr Drugs. 2000;2:113-26. PMID: 10937463
13. Steen B, Rane A, Lonnerholm G et al. Phenytoin excretion in human breast milk and plasma levels in nursed infants. Ther Drug Monit. 1982;4:331-4. PMID: 7157456
14. Finch E, Lorber J. Methaemoglobinaemia in the newborn. Probably due to phenytoin excreted in human milk. J Obstet Gynaecol Br Emp. 1954;61:833-4. PMID: 13222209
15. Livingston S. Treatment of epilepsy with diphenylhydantoin sodium (Dilantin sodium). Postgrad Med. 1956;20:584-6.
16. Kok TH, Taitz LS, Bennett MJ et al. Drowsiness due to clemastine transmitted in breast milk. Lancet. 1982;319:914-5. Letter. PMID: 6122135
17. Kaneko S, Suzuki K, Sato T et al. The problems of antiepileptic medication in the neonatal period: is breast-feeding advisable? In: Janz D, Dam M, Richens A et al. Epilepsy, pregnancy and the child. New York: Raven Press, 1982:343-8.
18. Granstrom ML, Bardy AH, Hiilesmaa VK. Prolonged feeding difficulties of infants of primidone mothers during neonatal period: preliminary results from the Helsinki study. In: Janz D et al., eds. Epilepsy, pregnancy and the child. New York: Raven Press, 1982:357-8.
19. Koch S, Gopfert-Geyer I, Hauser I et al. Neonatal behaviour disturbances in infants of epilepetic women treated during pregnancy. Prog Clin Biol Res. 1985;163B:453-61. PMID: 3983173
20. Meador KJ, Baker GA, Browning N et al. Effects of breastfeeding in children of women taking antiepileptic drugs. Neurology. 2010;75:1954-60. PMID: 21106960
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
