Oseltamivir or zanamivir – can they be used in breastfeeding mothers for the treatment or prophylaxis of influenza?

7 August 2020This updated Medicines Q&A evaluates the available evidence for oseltamivir and zanamivir when used in breastfeeding mothers for the treatment or prophylaxis of influenza. In…
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Lactation Safety Information

Inhalation, intravenous

Inhalation, intravenous
No published evidence of safety
Minimal absorption from the infant's GI tract
Monitor infant for vomiting and diarrhoea, especially after maternal intravenous administration
If an infant being breastfed by a mother receiving zanamavir needs direct treatment or chemoprophylaxis, the recommended dose for infants should still be given
12 October 2020

New Medicines

DectovaInfluenza - treatment of hospitalised patients


New formulation

Development and Regulatory status

Phase III Clinical Trials
November 2019
Nov 19Available in the UK; cost per vial is £27.83 [9].
Apr 19Licensed in Europe. Launch Planned Q4 2019. [8]
Feb 19Recommended for EU approval by CHMP - the full indication is "for the treatment of complicated and potentially life-threatening influenza A or B virus infection in adult and paediatric patients (aged ≥6 months) when - The patient’s influenza virus is known or suspected to be resistant to anti-influenza medicinal products other than zanamivir, and/or - Other anti-viral medicinal products for treatment of influenza, including inhaled zanamivir, are not suitable for the individual patient. Dectova should be used in accordance with official guidance” [7].
Jan 18Zanamivir is under evaluation by the EU CHMP; assume this formulation [5].
Mar 17Remains PIII [3].


Neuraminidase inhibitor active against influenza A and B viruses. It prevents viral release from infected cells and subsequent infection of adjacent cells.
Up to 15% of the population can develop influenza in any year. There is a 10-20% seroconversion rate with or without symptoms. In an average year, there are 50-200 GP consultations for influenza or flu-like illnesses per 100,000 population per week.[3]It is highly infectious with a ratio of infections to clinical cases of between 3:1 and 9:1. Risks of complications with hospitalisation and death are higher among those aged >65 years, very young children and those with at-risk factors [4].
Influenza - treatment of hospitalised patients
Intravenous infusion

Further information

To be confirmed

Trial or other data

Mar 15GSK completes a PIII trial, which compared IV zanamivir (300mg or 600mg) with oral oseltamivir for hospitalised adolescent and adult patients with influenza (ZORO; NCT01231620). The primary endpoint of the randomised, double-blind trial was the time to clinical response in patients with confirmed influenza. The global trial enrolled 626 patients in the US, Brazil, Canada, Columbia, Mexico, South Africa, Australia, New Zealand, Belgium, Norway, Russia, Taiwan, Thailand, South Korea, China, Hong Kong, India and the EU [2].

Evidence based evaluations