Zanamivir is an inhaled neuraminidase inhibitor used in the treatment of influenza infection (licensed for use within 48 hours of the first symptoms), for post-exposure prophylaxis in at-risk groups when influenza is circulating in the community, and in exceptional circumstances to prevent influenza in a pandemic. Currently, zanamivir is not recommended for seasonal prophylaxis against influenza.
The available data relating to zanamivir exposure in human pregnancy do not indicate increased risk of adverse pregnancy outcome, but are too limited to rule out such a risk. Systemic absorption of zanamivir after inhalation is low and the risk of adverse fetal effects is therefore expected to be lower than any hypothetical risk posed by systemically administered neuraminidase inhibitors. Due to the established risks of maternal influenza infection during pregnancy, zanamivir should not be withheld if compellingly indicated.
Exposure to zanamivir at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors which independently increase the risk of adverse pregnancy outcome may be present in individual cases. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.