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Zanamivir Pregnancy and Breastfeeding Warnings

Zanamivir is also known as: Relenza

Medically reviewed on Sep 25, 2018

Zanamivir Pregnancy Warnings

Zanamivir has been assigned to pregnancy category C by the FDA. High-dose animal studies have failed to reveal evidence of embryotoxicity, teratogenicity, or maternal toxicity. Another high-dose study (1000 times the human exposure) found minor skeletal changes and variants; however, the incidence was not significantly different than the background incidence for the strain. Although zanamivir has been shown to cross the placenta in animal studies, drug concentrations in fetal blood have been significantly lower than those in maternal blood. There are no controlled data in human pregnancy. Zanamivir should only be given during pregnancy when benefit outweighs risk.

See references

Zanamivir Breastfeeding Warnings

There are no data on the excretion of zanamivir into human milk. Zanamivir is excreted into the milk of rats.

See references

References for pregnancy information

  1. "Antiviral drugs prophylaxis and treatment of influenza." Med Lett Drugs Ther 48 (2006): 87-8
  2. "Product Information. Relenza (zanamivir)" Glaxo Wellcome, Research Triangle Pk, NC.

References for breastfeeding information

  1. "Product Information. Relenza (zanamivir)" Glaxo Wellcome, Research Triangle Pk, NC.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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