Karen Libby


General description

Zanamivir (generic name Relenza) is an orally inhaled antiviral, effective for the treatment of Influenza A or B infections in adults. It is also under investigation for influenza prophylaxis.


Zanamivir inhibits influenza virus neuraminidase with the possibility of alteration of virus particle aggregation and release.


Indicated for treatment of uncomplicated influenza in adults and adolescents 12 years and older who have been symptomatic for no more than 2 days.


The recommended dosage for treatment of influenza in patients over 12 years of age is 2 doses of 5 mg each (for a total dose of 10 mg) twice daily (approximately 12 hours apart) for 5 days. Two doses should be taken on the first day of treatment whenever possible provided there is at least 2 hours between doses. On subsequent days, doses should be about 12 hours apart (e.g., morning and evening) at approximately the same time each day.


Zanamivir use should be avoided if the patient is undergoing any concurrent use of inhaled medications, or the patient is pregnant or breastfeeding. Also, it is important to initiate treatment early for efficacy (ie, within 48 hours).


Zanamivir is contraindicated in patients with a known hypersensitivity to any component of the formulation. It has not been evaluated in high-risk patient groups.

Potential Adverse Effects

Adverse effects are well-tolerated. No serious adverse events have been observed.


Sources: http://www.relenza.com/, http://www.glaxowellcome.com