Drug Interactions

Guidance on the Use of Influenza Antiviral Agents

(Current for the 2012-2013 Influenza Season)
 

Clinical data are limited regarding drug interactions with zanamivir. No known drug interactions have been reported, and no clinically critical drug interactions have been predicted on the basis of in vitro and animal study data [116, 232].

Limited clinical data are available regarding drug interactions with oseltamivir. Because oseltamivir and oseltamivir carboxylate are excreted in the urine by glomerular filtration and tubular secretion via the anionic pathway, a potential exists for interaction with other agents excreted by this pathway. For example, coadministration of oseltamivir and probenecid resulted in reduced clearance of oseltamivir carboxylate by approximately 50% and a corresponding approximate twofold increase in the plasma levels of oseltamivir carboxylate [163].

No published data from clinical trials are available concerning the safety or efficacy of using combinations of different classes of influenza antiviral drugs. One recent study suggested that use of oseltamivir plus zanamivir was less efficacious than monotherapy with either drug alone [233]. Providers should consult package inserts for more detailed information about potential drug interactions.

Review the references cited in this guidance.