Isoniazid / rifampin Pregnancy and Breastfeeding Warnings
Brand names: IsonaRif, Rifamate
Isoniazid / rifampin Pregnancy Warnings
Use is recommended during pregnancy only if the potential benefit outweighs the possible risk to the fetus.
US FDA pregnancy category: C
Comments:
-When administered during the last few weeks of pregnancy, rifampin can cause postnatal hemorrhages in the mother and infant for which treatment with vitamin K may be indicated.
-Rifampin may affect the reliability of oral or other systemic hormonal contraceptives; advise patients to use alternative birth control methods during treatment.
-Both isoniazid and rifampin have been reported to cross the placental barrier; rifampin has appeared in cord blood.
Animal studies have revealed evidence of teratogenicity (including cleft palate and spina bifida) with use of rifampin at doses 0.2 to 2 times the maximum recommended human (MRH) dose. Imperfect osteogenesis and embryotoxicity in animals were also reported at oral rifampin doses about 3 times the MRH dose. Isoniazid may exert an embryocidal effect; however, no isoniazid-related congenital anomalies have been found in animal reproduction studies in mammalian species. There are no controlled data in human pregnancy.
US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Isoniazid / rifampin Breastfeeding Warnings
A decision should be made to discontinue breastfeeding or to discontinue this drug, taking into account the importance of this drug to the mother.
Excreted into human milk: Yes
Comments:
-The Centers for Disease Control and Prevention and other professional organizations state breastfeeding should not be discouraged in women taking rifampin and/or isoniazid.
-Limited data indicates that the low levels of isoniazid and rifampin in breastmilk would not be expected to cause any adverse effects in breastfed infants; however, monitor infants for rare instances of jaundice.
-There is a theoretical risk of convulsions and neuropathy (associated with pyridoxine/Vitamin B6 deficiency) in breastfed infants of mothers taking isoniazid; instruct breastfeeding mothers to administer the one-daily dose of this combination drug before the infant's longest sleep period to decrease the dose the infant receives.
-Advise nursing mothers to concomitantly take 25 mg of oral pyridoxine daily and to give their breastfed infants 1 mg/kg of pyridoxine daily during treatment with this combination drug.
-In mothers given single oral doses of isoniazid, average peak drug levels in breastmilk occurred at 2 to 3 hours after the dose: 2.1 mg/L (200 mg dose), 5.4 to 5.5 mg/L (300 mg dose), and 9 to 10.6 mg/L (600 mg dose).
-After a single 150 mg oral dose of rifampin, drug levels in breastmilk 4 hours after the dose ranged from 0 to 1.8 mL. After a single oral dose of 450 mg, breastmilk levels 12 hours after the dose ranged from 3.4 to 4.9 mg/L.
-The breastfed infants of mothers who took isoniazid 300 mg once daily for at least 34 days received about 0.3% to 1.2% of the maternal-adjusted dosage of isoniazid.
-Normal development was observed in 4 breastfed children (ages 3.9 to 5.1 years) of mothers who received isoniazid and/or rifampin throughout pregnancy and postpartum as part of a multi-drug treatment regimen for tuberculosis; only hyperactivity in 1 child and a mild speech delay in another were noted.
See also
References for pregnancy information
- (2001) "Product Information. Rifamate (isoniazid-rifampin)." Aventis Pharmaceuticals
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
References for breastfeeding information
- (2001) "Product Information. Rifamate (isoniazid-rifampin)." Aventis Pharmaceuticals
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
- United States National Library of Medicine (2013) Toxnet. Toxicology Data Network. http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.