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Isoniazid / pyrazinamide / rifampin Pregnancy and Breastfeeding Warnings

Isoniazid / pyrazinamide / rifampin is also known as: Rifater

Isoniazid / pyrazinamide / rifampin Pregnancy Warnings

Animal studies have not been conducted with this drug or pyrazinamide, but they have been conducted with rifampin and isoniazid. Congenital malformations (spina bifida and cleft palate) have been observed with rifampin at doses 0.2 to 2 times the maximum recommended human dose (MRHD); imperfect osteogenesis and embryotoxicity were also reported at doses about 3 times the MRHD. Isoniazid may exert an embryocidal effect, although no isoniazid-related congenital anomalies have been found in animals. 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.

Safety has not been established during pregnancy; this drug should be used during pregnancy only if the benefit outweighs the risk to the fetus. US FDA pregnancy category: C Comments: -When administered during the last few weeks of pregnancy, rifampin can cause post-natal hemorrhages in the mother and infant for which Vitamin K treatment may be indicated. -Occasional disturbances of the menstrual cycle have been reported in women receiving long-term anti-tuberculosis therapy containing rifampin. -Female patients of reproductive potential should be advised to consider using non-hormonal methods of birth control as this drug may affect the reliability of oral and other systemic hormonal contraceptives.

See references

Isoniazid / pyrazinamide / rifampin Breastfeeding Warnings

Isoniazid passes into breastmilk in concentrations comparable to those in the plasma. Pyrazinamide and rifampin produce low levels in breastmilk and would not usually be expected to cause any adverse effects in breastfed infants. The amount of isoniazid, pyrazinamide, and rifampin in breastmilk is insufficient to treat tuberculosis in the breastfed infant.

Breastfeeding is not recommended during treatment unless the potential benefit to the patient outweighs the potential risk to the infant. Excreted into human milk: Yes Excreted into animal milk: Data not available Comments: -Breastfed infants whose mothers are taking isoniazid should be monitored for early signs of convulsions and neuropathy (associated with pyridoxine deficiency) and rare cases of jaundice, hepatitis, and arthralgia. -The US CDC, Infectious Diseases Society of America, and the American Thoracic Society recommend that breastfeeding should not be discouraged in women taking isoniazid, pyrazinamide, and rifampin. However, these professional organizations recommend nursing mothers take 25 mg of oral pyridoxine (Vitamin B6) daily while receiving isoniazid.

See references

References for pregnancy information

  1. "Product Information. Rifater (isoniazid/pyrazinamide/rifampin)." SmithKline Beecham, Philadelphia, PA.

References for breastfeeding information

  1. "Product Information. Rifater (isoniazid/pyrazinamide/rifampin)." SmithKline Beecham, Philadelphia, PA.
  2. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL:" ([cited 2013 -]):

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