Oseltamivir Carboxylate

Oseltamivir phosphate is an ethyl ester prodrug. Oseltamivir carboxylate has an antiviral spectrum and potency similar to that of zanamivir. It inhibits amantadine- and rimantadine-resistant influenza A viruses and some zanamivir-resistant variants.

mechanisms of action and resistance Influenza neuraminidase cleaves terminal sialic acid residues and destroys the receptors recognized by viral hemagglutinin, which are present on the cell surface, in progeny virions, and in respiratory secretions, which is essential for virus release from infected cells. Oseltamivir carboxylate causes a conformational change in neu-raminidase's active site and inhibits its activity, leading to viral aggregation at the cell surface and reduced virus spread within the respiratory tract.

Influenza variants selected in vitro for resistance to oseltamivir carboxylate contain hemagglu-tinin and/or neuraminidase mutations. The most commonly recognized resistant variants have reduced infectivity and virulence in animal models. Outpatient oseltamivir therapy has been associated with recovery of resistant variants in ~0.5% of adults and 5.5% of children; a higher frequency (~18%) occurs in hospitalized children.


Oral oseltamivir phosphate is absorbed rapidly (Table 49-3) and cleaved to the active carboxylate by esterases in the GI tract and liver. The bioavailability of the carboxylate is ~80%; food does not decrease bioavailability but reduces GI symptoms. The carboxylate has a volume of distribution similar to extracellular water. Both prodrug and active metabolite are eliminated primarily unchanged by the kidney.

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook

Post a comment