You need to be logged in to see the full monograph.


Date of issue: July 2022, Version: 3

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.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from to ensure you are using the most up-to-date version.