Oseltamivir

The medicinal substance Oseltamivir belongs to the class of neuraminidase inhibitors. It is used to prevent and treat influenza flu. Side effects can occur.

What is oseltamivir?

Oseltamivir is a drug that belongs to the class of neuraminidase inhibitors. The product is suitable for the therapy and prophylaxis of the real flu, which is caused by the influenza virus.

Oseltamivir is one of the so-called prodrugs. After oral ingestion of the active ingredient, the ester bond is split. This is where the actual active form, called oseltamivir carboxylate, emerges. Oseltamivir is also known under the product name Tamiflu®. It is a prescription drug and can only be obtained from a pharmacy upon presentation of a prescription.

Oseltamivir was developed by the Austrian biochemist Norbert Bischofberger, who worked for the biotechnology company Gilead Sciences in Foster City, California in the 1990s. Bischofberger was researching an anti-flu drug that could also be administered in tablet form. After this was successful, the biochemist worked with the pharmaceutical company Roche. Finally, oseltamivir was approved in Switzerland in 1999. The USA joined in 2000 and from 2002 the drug could also be marketed in the EU.

There was initially the restriction that only patients over 13 years of age could be treated. However, this restriction was later lifted so that oseltamivir therapy can now be given to children from one year of age. Over time, Tamiflu® has become one of Roche's most successful pharmaceuticals. Generics of oseltamivir have also been available since 2014.

Pharmacological effect

As a neuraminidase inhibitor, oseltamivir is an antiviral agent. Neuraminidase is an enzyme that contributes to the release of the influenza virus from a host cell. The neuraminidase breaks the bond between hemagglutinin, which is located on the surface of the virion, and glycolipids, which are located on the surface of the host cell. This process releases the virion from an infected cell, causing infections to occur in other cells.

The viruses that have newly emerged in the body's cells infect the other cells after they have left a cell, whereby their spread takes place. In order to be able to leave the cell, the neuraminidase has to cut a link between the cell and the virus.

Oseltamivir counteracts this process by blocking the enzyme. In this way, the active ingredient prevents the viruses from infecting other body cells. This gives the human immune system the opportunity to more easily fight the immobile viruses.

Oseltamivir is administered orally. After ingestion, the active ingredient is completely absorbed. Within the liver, the prodrug oseltamivir is converted into the active oseltamivir carboxylate with various esterases. The active metabolite is not further metabolized, so that it is excreted unchanged from the body via the kidneys. There is greater bioavailability in older patients.

Oseltamivir has the ability to shorten the duration of the flu and alleviate its symptoms, provided that treatment starts no later than 48 hours after the onset of the illness. In addition, its use reduces the risk of bacterial superinfection.

Medical application & use

Oseltamivir is used in the treatment and prevention of influenza flu, which has nothing to do with the harmless flu-like infection (cold). In order for the active ingredient to develop its positive effects, however, it must be taken within 48 hours. In order to have a preventive effect, it must be taken promptly after contact with infected people.

The dosage in children depends on their age and weight. However, it may only be administered to babies in severe exceptional cases. Oseltamivir does not cure influenza flu, but the active substance can reduce the duration of the illness and relieve symptoms.

The neuraminidase inhibitor is not a suitable alternative to the flu vaccination. The agent should only be used during influenza epidemics and under medical supervision.

Risks & side effects

The occurrence of undesirable side effects is possible when taking oseltamivir. Those affected often suffer from stomach pain, nausea and vomiting. Occasionally, allergic reactions occur and existing respiratory diseases can worsen. To avoid gastrointestinal discomfort caused by oseltamivir, it is recommended to take the drug with some food.

Other possible side effects of oseltamivir can be headache, cardiac arrhythmia, skin rashes, seizures, hypersensitivity reactions, eczema, inflammation of the skin, hives, increased liver values ​​or impaired consciousness. Fear, severe inflammation of the liver, abnormal behavior, confusion, gastrointestinal bleeding, visual disturbances, nightmares and delusions are also rare. In rare cases, adolescents self-harmed.

If there is hypersensitivity to oseltamivir, therapy with the active ingredient must not be given. The positive effect of the agent in people who suffer from a weak immune system or chronic diseases is not certain. You should only receive the drug in exceptional cases.

During pregnancy and breastfeeding, the doctor must carefully weigh up the administration of oseltamivir. So it is unknown whether the child can be harmed by the drug. Oseltamivir is only given to children younger than one year in the event of a large influenza outbreak.