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Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

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Drugs and Lactation Database (LactMed) [Internet].

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Last Revision: September 21, 2020.

Estimated reading time: 2 minutes

CASRN: 98-96-4

image 134971473 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Limited information indicates that maternal pyrazinamide therapy produces low levels in milk and would not usually be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Exclusively breastfed infants should be monitored for rare cases of jaundice, hepatitis and arthralgia if this drug is used during lactation.[1] The amount of pyrazinamide in milk is insufficient to treat tuberculosis in the breastfed infant. The Centers for Disease Control and Prevention and other professional organizations state that breastfeeding should not be discouraged in women taking pyrazinamide.[2-4]

Drug Levels

Maternal Levels. One woman who was lactating, but not breastfeeding (time postpartum not stated) was given a single oral dose of 1 gram of pyrazinamide. A peak milk level of 1.5 mg/L occurred 3 hours after the dose. The half-life of the drug in milk was estimated to be 9 hours.[1] Using these data, a fully breastfed infant would receive a maximum of about 1.4% of the maternal weight-adjusted dosage.

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Pyrazinamide was used as part of multi-drug regimens to treat 2 pregnant women with multidrug-resistant tuberculosis throughout pregnancy and postpartum. Their two infants were breastfed (extent and duration not stated). At age 1.25 and 5.1 years, the children were developing normally.[5]

Two mothers in Turkey were diagnosed with tuberculosis at the 30th and 34th weeks of pregnancy. They immediately started isoniazid 300 mg, rifampin 600 mg, pyridoxine 50 mg daily for 6 months, plus pyrazinamide 25 mg/kg and ethambutol 25 mg/kg daily for 2 months. Both mothers breastfed their infants (extent not stated). Their infants were given isoniazid 5 mg/kg daily for 3 months prophylactically. Tuberculin skin tests were negative after 3 months and neither infant had tuberculosis at 1 year of age. No adverse effects of the drugs were mentioned.[6]

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.


Holdiness MR. Antituberculosis drugs and breast-feeding. Arch Intern Med 1984;144:1888. Letter. PMID: 6548112. [PubMed: 6548112]
Blumberg HM, Burman WJ, Chaisson RE, et al. American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: treatment of tuberculosis. Am J Respir Crit Care Med. 2003;167:603–62. [PubMed: 12588714]
Anon. Treatment of tuberculosis. MMWR Recomm Rep. 2003;52:1–77. [PubMed: 12836625]
Bartlett JG. Guidelines section. Infect Dis Clin Pract. 2002;11:467–71. [CrossRef]
Drobac PC, del Castillo H, Sweetland A, et al. Treatment of multidrug-resistant tuberculosis during pregnancy: long-term follow-up of 6 children with intrauterine exposure to second-line agents. Clin Infect Dis. 2005;40:1689–92. [PubMed: 15889370]
Keskin N, Yilmaz S. Pregnancy and tuberculosis: To assess tuberculosis cases in pregnancy in a developing region retrospectively and two case reports. Arch Gynecol Obstet. 2008;278:451–5. [PubMed: 18273625]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Anti-infective Agents

Antitubercular Agents

Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.


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