Relenza Use In Pregnancy & Lactation

Pregnancy: Systemic exposure to zanamivir is low following administration by inhalation; however, there is no information on placental transfer of zanamivir in humans. There is a limited amount of data (less than 300 pregnancy outcomes) from the use of zanamivir in pregnant women. Animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity (see Pharmacology: Toxicology: Preclinical safety data under Actions).
As a precautionary measure, it is preferable to avoid the use of Relenza during pregnancy, unless the clinical condition of the woman is such that the potential benefit to the mother significantly outweighs the possible risk to the foetus.
Breastfeeding: Systemic exposure to zanamivir is low following administration by inhalation; however, there is no information on secretion of zanamivir into human breast milk. A risk to the breastfed child cannot be excluded. A decision must be made whether to discontinue breastfeeding or to discontinue/abstain from Relenza therapy, taking into account the benefit of breastfeeding for the child and the benefit of therapy for the woman.
Fertility: Animal studies indicate no clinically meaningful effects of zanamivir on male or female fertility (see Pharmacology: Toxicology: Preclinical safety data under Actions).