The active medical ingredient oseltamivir belongs to the neuraminidase inhibitor class. It is used to prevent and treat influenza flu. Side effects may include.
What is oseltamivir?
Oseltamivir is a drug that belongs to the class of neuraminidase inhibitors. The drug is suitable for the treatment and prophylaxis of true influenza, which is caused by the influenza virus. Oseltamivir belongs to the so-called prodrugs. After oral administration of the active ingredient, the ester bond is cleaved. This results in the actual active form called oseltamivir carboxylate. Oseltamivir is also known under the product name Tamiflu. It is a prescription-only drug and is only available from pharmacies on 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-influenza drug that could also be administered in tablet form. After this was achieved, the biochemist worked with the pharmaceutical company Roche. Finally, oseltamivir was approved in Switzerland in 1999. In 2000, the U.S. joined in, and from 2002, the drug could also be marketed in the EU. Initially, there was a restriction that only patients over the age of 13 could be treated. However, this restriction was later lifted, so that oseltamivir therapy can now be given to children as young as one year. Over time, Tamiflu advanced to become Roche’s most successful medicines. Generic versions of oseltamivir have also been available since 2014.
Pharmacological action
As a neuraminidase inhibitor, oseltamivir is a virus-inhibiting agent. Neuraminidase is an enzyme that participates in the release of influenza virus from a host cell. Neuraminidase cleaves 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 results in the release of the virion from an infected cell, causing infections to occur on additional cells. The viruses that have newly emerged in the body cells infect the other cells after they have left a cell again, causing their spread. In order to leave the cell, it is necessary for the neuraminidase to cut a connector 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 any more body cells. This gives the human immune system the opportunity to fight the immobilized viruses more easily. Oseltamivir is administered orally. After its ingestion, complete absorption of the active ingredient occurs. Within the liver, conversion of the prodrug oseltamivir to the active oseltamivir carboxylate takes place with different esterases. No further metabolism of the active metabolite occurs, so that it is excreted unchanged from the body via the kidneys. Greater bioavailability is present in patients of older age. Oseltamivir has the property of shortening the duration of influenza and alleviating its symptoms, provided that treatment begins no later than 48 hours after the onset of illness. In addition, its use reduces the risk of bacterial superinfection.
Medical application and use
The field of application of oseltamivir is the treatment and prevention of influenza flu, which has nothing to do with the harmless flu-like infection (common cold). However, for the active ingredient to exert its positive effects, it must be taken within 48 hours. For a preventive effect, it must be taken soon after contact with infected persons. The dosage for children depends on their age and weight. However, administration in babies should be done only in severe exceptional cases. Oseltamivir cannot cure influenza flu, but the active ingredient can reduce the duration of the illness and alleviate symptoms. Neuraminidase inhibitor is not suitable as an alternative to influenza vaccination. The agent should only be used during flu epidemics and under medical supervision.
Risks and side effects
By taking oseltamivir, the occurrence of undesirable side effects is possible. In this case, those affected often suffer from stomach pain, nausea and vomiting. Sometimes allergic reactions also appear and existing respiratory diseases can worsen. To avoid gastrointestinal complaints caused by oseltamivir, it is recommended to take the drug with some food. Other conceivable side effects of oseltamivir may include headache, cardiac arrhythmias, skin rashes, seizures, hypersensitivity reactions, eczema, inflammation of the skin, hives, elevated liver enzymes, or impairment of consciousness. Rarely, anxiety, marked liver inflammation, abnormal behavior, confusion, gastrointestinal bleeding, visual disturbances, nightmares, and delusions also occur. In rare cases, self-injury has occurred in adolescents. If hypersensitivity to oseltamivir is present, therapy with the active substance must not be given. The positive effect of the drug is not certain in people suffering from a weakness of the immune system or chronic diseases. They should receive the drug only in exceptional cases. In the context of pregnancy and breastfeeding, the doctor must thoroughly weigh up the administration of oseltamivir. For example, it is unknown whether the child may be harmed by the drug. Children younger than one year of age receive oseltamivir only in the event of a large-scale influenza outbreak.
