Products
Oseltamivir is commercially available as capsules and as a powder for oral suspension (Tamiflu). It has been approved in many countries since 1999. Generics were first registered in the EU in 2014 (ebilfumin) and in many countries in 2018.
Structure and properties
Oseltamivir (C16H28N2O4, Mr = 312.4 g/mol) is present in drugs as oseltamivir phosphate, a white powder that is readily soluble in water. It is a prodrug and is biotransformed in the intestine and liver by esterases to the active metabolite oseltamivir carboxylate.
Effects
Oseltamivir (ATC J05AH02) has antiviral properties against influenza viruses. It reduces the duration and severity of illness. The effects are due to inhibition of viral neuraminidase and thus replication of the virus. Neuraminidase is central on the surface of influenza viruses for the release of newly formed viruses from infected cells and thus for the further spread of infectious viruses in the organism. Note also the following descriptive animation: Tamiflu animation.
Indications
For the prevention and treatment of influenza (influenza types A and B).
Dosage
According to the drug label. Treatment should be started as early as possible, ideally within 36 hours. Therapeutically, the drug is usually taken twice daily for 5 days. Administration is independent of meals. Taking it with food may improve tolerability.
Contraindications
- Hypersensitivity
For complete precautions, see the drug label.
Interactions
The active metabolite oseltamivir carboxylate is an organic anion and is subject to active tubular secretion at the kidney. Therefore, other organic anions with a narrow therapeutic range, such as methotrexate, should not be administered concomitantly or should be administered with caution. Probenecid inhibits tubular secretion, resulting in a twofold increase in systemic availability. No dose adjustment is necessary.
Adverse effects
The most common potential adverse effects include nausea, vomiting, headache, and pain.
