The Basics
What is Phenobarbital?
Used to control seizures, relieve anxiety, and prevent withdrawal symptoms.
Brand names for Phenobarbital
Phenobarbital
How Phenobarbital is classified
Anticonvulsants, Barbiturates, Hypnotics and Sedatives, GABA Modulators
Phenobarbital During Pregnancy
Phenobarbital 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 Phenobarbital while pregnant
Phenobarbital can cause fetal damage when administered to a pregnant woman. Retrospective case-controlled studies have suggested a connection between the maternal consumption of phenobarbital and higher than expected incidence of fetal abnormalities. Following oral administration, Phenobarbital readily crosses the placental barrier and is distributed throughout fetal tissues with highest concentrations found in the placenta, fetal liver, and brain. Withdrawal symptoms occur in infants born to mothers who receive phenobarbital throughout the last trimester of pregnancy. (See ADVERSE REACTIONS: Drug Abuse and Dependence.) If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
Taking Phenobarbital While Breastfeeding
What are recommendations for lactation if you're taking Phenobarbital?
Inter- and intrapatient variability in excretion of phenobarbital into breastmilk is extensive. Phenobarbital in breastmilk apparently can decrease withdrawal symptoms in infants who were exposed in utero, but it can also cause drowsiness in some infants, especially when used with other sedating drugs. Monitor the infant for drowsiness, adequate weight gain, and developmental milestones, especially in younger, exclusively breastfed infants and when using combinations of psychotropic drugs. Sometimes breastfeeding might have to be limited or discontinued because of excessive drowsiness and poor weight gain. If there is concern, measurement of the infant’s serum phenobarbital concentration might help rule out toxicity.
Maternal / infant drug levels
Inter- and intrapatient variability in excretion of phenobarbital into breastmilk is extensive. Phenobarbital in breastmilk apparently can decrease withdrawal symptoms in infants who were exposed in utero, but it can also cause drowsiness in some infants, especially when used with other sedating drugs. Monitor the infant for drowsiness, adequate weight gain, and developmental milestones, especially in younger, exclusively breastfed infants and when using combinations of psychotropic drugs. Sometimes breastfeeding might have to be limited or discontinued because of excessive drowsiness and poor weight gain. If there is concern, measurement of the infant’s serum phenobarbital concentration might help rule out toxicity.
Possible effects of Phenobarbital on milk supply
No direct effect is known, but mothers taking antiepileptic drugs stop breastfeeding earlier and supplement more than mothers not taking antiepileptic drugs. Most of these reports occurred in older studies in which sedating agents such as phenobarbital and primidone were used. Infant sucking difficulties and sedation were reasons given for the reduced nursing.[12][14]
Possible alternatives to Phenobarbital
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. Westerink D, Glerum JH. [Separation and microdetermination of phenobarbital and phenytoin in human milk]. Pharm Weekbl. 1965;100:577-83. PMID: 14343657
2. 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.
3. Kaneko S, Sato T, Suzuki K. The levels of anticonvulsants in breast milk. Br J Clin Pharmacol. 1979;7:624-7. Letter. PMID: 465285
4. Gomita Y, Furuno K, Araki Y et al. Phenobarbital in sera of epileptic mothers and their infants. Am J Ther. 1995;2:968-71. PMID: 11854816
5. Shimoyama R, Ohkubo T, Sugawara K. Characteristics of interaction between barbiturate derivatives and various sorbents on liquid chromatography and determination of phenobarbital in Japanese human breast milk. J Liq Chromatogr Relat Technol. 2000;23:587-99.
6. 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.
7. Pote M, Kulkarni R, Agarwal M. Phenobarbital toxic levels in a nursing neonate. Indian Pediatr. 2004;41:963-4. Letter. PMID: 15475647
8. Tyson RM, Shrader EA, Perlman HH. Drugs transmitted through breast milk, II: Barbituates. J Pediatr. 1938;13:86-90.
9. 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
10. Juul S. [Barbiturate poisoning via breast milk?]. Ugeskr Laeger. 1969;131:2257-8. PMID: 5372729
11. Gopfert-Geyer I, Koch S, Rating D et al. Delivery, gestation, data at birth, and neonatal period in children of epileptic mothers. In: Janz D, Bossi L, Dam M et al., eds. Epilepsy, pregnancy and the child. New York: Raven Press, 1982:179-87.
12. 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.
13. Knott C, Reynolds F, Clayden G. Infantile spasms on weaning from breast milk containing anticonvulsants. Lancet. 1987;330:272-3. Letter. PMID: 2886736
14. Hartmann AM, Koch S, Jager-Roman E, Helge H. [Breast feeding, weight gain and behaviour in newborns of epileptic women]. Monatsschr Kinderheilkd. 1994;142:505-12.
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.
