Is Pyrazinamide safe while breastfeeding?
Here is what NIH LactMed, the U.S. National Library of Medicine's authority on medicines and breastfeeding, reports about Pyrazinamide. This is a summary of that source — not our own verdict.
Effects on the breastfed infant
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 T rkiye 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 milk supply
Relevant published information was not found as of the revision date.
Levels in milk
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. Two breastfeeding women with tuberculosis were receiving pyrazinamide as well as at least 4 other antituberculars donated 1 mL breastmilk samples by manual expression at approximately 6 weeks postpartum. Samples were obtained immediately prior to a dose and 2, 4, and 6 hours after a dose of 1750 mg of pyrazinamide. Peak milk pyrazinamide concentrations of 38.4 and 59.2 mg/L occurred at about 4 hours after a dose. The authors used the peak concentrations to calculate infant daily dosages of 5.76 and 8.88 mg/kg, which ranged from 14 to 30% of the infant dosage and 17 to 28% of the maternal weight-adjusted dosage. These values may be overestimates because peak milk concentrations were used rather than average concentrations.[ 3 ] Another group of authors used data from this study and other pharmacokinetic studies to estimate infant dosages of 7.1 and 10.9 mg/kg daily in these patients which represent 47% and 73% of the infant dosage. However, the authors used a nonstandard milk volume in their calculation. Using the standard 150 mL/kg daily, the estimated infant dosages would be 5.8 and 8.8 mg/kg daily in these patients, which represent 38% and 59% of the infant dosage.[ 4 ] Infant Levels. Relevant published information was not found as of the revision date.
Source: NIH LactMed (National Library of Medicine).
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.