Last update: May 1, 2016


Very Low Risk for breastfeeding

Safe. Compatible.
Not risky for breastfeeding or infant.

Type IB antiarrhythmic agent and anticonvulsant drug.

It is excreted into breast milk in clinically non-significant amount and no problems have appeared on clinical follow up, and, long-term psychomotor development in infants whose mothers received this treatment, except in some isolated cases of patients who were on anticonvulsant polytherapy.
Plasma levels in these infants were undetectable or very low.

It may appear a withdrawal syndrome with hyperexcitability after abruptly stopping breastfeeding.

It has been authorized for use in infants and newborns.

American Academy of Pediatrics states that it is usually compatible with breastfeeding medication.
WHO List of Essential Medicines 2002: compatible with breastfeeding.


We do not have alternatives for Phenytoin since it is relatively safe.

Suggestions made at e-lactancia are done by APILAM´s pediatricians and pharmacists, and are based on updated scientific publications.
It is not intended to replace the relationship you have with your doctor but to compound it.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Phenytoin is also known as

Phenytoin in other languages or writings:


Phenytoin belongs to this group or family:


Main tradenames from several countries containing Phenytoin in its composition:


Variable Value Unit
Oral Bioavail. 70 - 100 %
Molecular weight 252 daltons
Protein Binding 89 %
VD 0,5 - 0,8 l/Kg
Tmax 4 - 12 hours
T1/2 6 - 24 hours
M/P ratio 0,2 - 0,5 -
Theoretical Dose 0,07 - 0,4 mg/Kg/d
Relative Dose 1,4 - 8 %
Relat.Ped.Dose 1 - 7 %


  1. Crettenand M, Rossetti AO, Buclin T, Winterfeld U. [Use of antiepileptic drugs during breastfeeding : What do we tell the mother?] Nervenarzt. 2018 Abstract
  2. Meador KJ, Baker GA, Browning N, Cohen MJ, Bromley RL, Clayton-Smith J, Kalayjian LA, Kanner A, Liporace JD, Pennell PB, Privitera M, Loring DW; Neurodevelopmental Effects of Antiepileptic Drugs (NEAD) Study Group. Breastfeeding in children of women taking antiepileptic drugs: cognitive outcomes at age 6 years. JAMA Pediatr. 2014 Abstract Full text (link to original source) Full text (in our servers)
  3. Davanzo R, Dal Bo S, Bua J, Copertino M, Zanelli E, Matarazzo L. Antiepileptic drugs and breastfeeding. Ital J Pediatr. 2013 Abstract Full text (link to original source) Full text (in our servers)
  4. Rowe H, Baker T, Hale TW. Maternal medication, drug use, and breastfeeding. Pediatr Clin North Am. 2013 Feb;60(1):275-94. Abstract
  5. Mercadé Cerdá JM, Sancho Rieger J, Mauri Llerda JA, López González FJ,Salas Puig X. Guías diagnósticas y terapéuticas de la Sociedad Española de Neurología 2012. 1. Guía oficial de práctica clínica en epilepsia. Guías SEN 2012 Full text (in our servers)
  6. Mintzer S. To test our guess that breast is best: anticonvulsants and breastfeeding. Epilepsy Curr. 2011 Abstract Full text (link to original source) Full text (in our servers)
  7. Meador KJ, Baker GA, Browning N, Clayton-Smith J, Combs-Cantrell DT, Cohen M, Kalayjian LA, Kanner A, Liporace JD, Pennell PB, Privitera M, Loring DW; NEAD Study Group. Effects of breastfeeding in children of women taking antiepileptic drugs. Neurology. 2010 Abstract Full text (link to original source) Full text (in our servers)
  8. O'Connor SE, Zupanc ML. Women and epilepsy. J Pediatr Pharmacol Ther. 2009 Abstract Full text (link to original source) Full text (in our servers)
  9. Harden CL, Pennell PB, Koppel BS, Hovinga CA, Gidal B, Meador KJ, Hopp J, Ting TY, Hauser WA, Thurman D, Kaplan PW, Robinson JN, French JA, Wiebe S, Wilner AN, Vazquez B, Holmes L, Krumholz A, Finnell R, Shafer PO, Le Guen C; American Academy of Neurology; et al. Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): vitamin K, folic acid, blood levels, and breastfeeding: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of... Neurology. 2009 Abstract Full text (link to original source) Full text (in our servers)
  10. Pennell PB. 2005 AES annual course: evidence used to treat women with epilepsy. Epilepsia. 2006 Abstract Full text (link to original source) Full text (in our servers)
  11. Pack AM. Therapy insight: clinical management of pregnant women with epilepsy. Nat Clin Pract Neurol. 2006 Abstract
  12. Tomson T. Gender aspects of pharmacokinetics of new and old AEDs: pregnancy and breast-feeding. Ther Drug Monit. 2005 Abstract
  13. O'Brien MD, Gilmour-White SK. Management of epilepsy in women. Postgrad Med J. 2005 Abstract Full text (link to original source) Full text (in our servers)
  14. Rubin ET, Lee A, Ito S. When breastfeeding mothers need CNS-acting drugs. Can J Clin Pharmacol. 2004 Fall;11(2):e257-66. Epub 2004 Dec 8. Abstract
  15. Pennell PB. Antiepileptic drug pharmacokinetics during pregnancy and lactation. Neurology. 2003 Abstract
  16. WHO / UNICEF. BREASTFEEDING AND MATERNAL MEDICATION Recommendations for Drugs in the Eleventh WHO Model List of Essential Drugs. Department of Child and Adolescent Health and Development (WHO/UNICEF) 2002 Full text (link to original source) Full text (in our servers)
  17. AAP - American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 Sep;108(3):776-89. Abstract Full text (link to original source) Full text (in our servers)
  18. Bar-Oz B, Nulman I, Koren G, Ito S. Anticonvulsants and breast feeding: a critical review. Paediatr Drugs. 2000 Mar-Apr;2(2):113-26. Review. Abstract
  19. Hägg S, Spigset O. Anticonvulsant use during lactation. Drug Saf. 2000 Jun;22(6):425-40. Review. Abstract
  20. Shimoyama R, Ohkubo T, Sugawara K, Ogasawara T, Ozaki T, Kagiya A, Saito Y. 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 Abstract
  21. Meyer FP, Quednow B, Potrafki A, Walther H. [Pharmacokinetics of anticonvulsants in the perinatal period]. Zentralbl Gynakol. 1988 Abstract
  22. Koch S, Göpfert-Geyer I, Häuser I, Hartmann A, Jakob S, Jäger-Roman E, Nau H, Rating D, Helge H. Neonatal behaviour disturbances in infants of epileptic women treated during pregnancy. Prog Clin Biol Res. 1985 Abstract
  23. Steen B, Rane A, Lönnerholm G, Falk O, Elwin CE, Sjöqvist F. Phenytoin excretion in human breast milk and plasma levels in nursed infants. Ther Drug Monit. 1982 Abstract
  24. Puckett JB, Butler WM, McFarland JA. Phenytoin and lactation. Arch Neurol. 1982 Abstract
  25. Nau H, Kuhnz W, Egger HJ, Rating D, Helge H. Anticonvulsants during pregnancy and lactation. Transplacental, maternal and neonatal pharmacokinetics. Clin Pharmacokinet. 1982 Abstract
  26. Kaneko S, Sato T, Suzuki K. The levels of anticonvulsants in breast milk. Br J Clin Pharmacol. 1979 Abstract Full text (link to original source) Full text (in our servers)
  27. Rane A, Garle M, Borgå O, Sjöqvist F. Plasma disappearance of transplacentally transferred diphenylhydantoin in the newborn studied by mass fragmentography. Clin Pharmacol Ther. 1974 Abstract
  28. Mirkin BL. Diphenylhydantoin: placental transport, fetal localization, neonatal metabolism, and possible teratogenic effects. J Pediatr. 1971 Abstract
  29. FINCH E, LORBER J. Methaemoglobinaemia in the newborn probably due to phenytoin excreted in human milk. J Obstet Gynaecol Br Emp. 1954 Abstract

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