Tamiflu
Meaning of Tamiflu: Timing dominates this one: it stops new virus particles escaping infected cells, so it does most good early, before the infection has peaked.
Definition of Tamiflu
Tamiflu is a brand name for oseltamivir phosphate, an antiviral medicine taken by mouth that acts only against influenza. It blocks neuraminidase, an enzyme on the surface of the influenza virus that newly built virus particles need in order to break free of the cell that produced them. Particles left stuck to that cell cannot go on to infect others.
How does blocking neuraminidase help?
Influenza carries two proteins on its surface that do opposite jobs. Hemagglutinin grips sugar molecules on the outside of a cell so the virus can get in. Neuraminidase cuts those same sugars, and copies of the virus need that cut to release themselves once they have been assembled inside. An antiviral that blocks the enzyme leaves the new particles tethered to the cell surface, so the number of cells infected in the next round falls sharply. The drug does not kill the virus and does not repair cells already damaged, which is why the benefit depends so heavily on how early it starts. It works against both influenza A and influenza B, and against no other organism: colds, respiratory syncytial virus and bacterial pneumonia are untouched by it.
What is it prescribed for?
| Use | What it aims to do |
|---|---|
| Treatment of confirmed or suspected influenza | Shorten the illness and reduce the chance of complications, when begun soon after symptoms start |
| Prevention after a known exposure | Reduce the chance that infection takes hold, for instance during an outbreak in a care home |
It is not a substitute for vaccination, which works by a different route entirely, by preparing the immune system in advance rather than interfering with a virus already present.
What else is worth knowing?
Nausea and vomiting are the most frequent unwanted effects and are more likely when the medicine is taken without food. The dose is reduced when kidney function is impaired, because the drug leaves the body through the kidneys. Influenza strains can develop changes in the neuraminidase enzyme that make them resistant, and surveillance tracks how common those strains are each season. Reports of confusion and unusual behavior, mostly in children and adolescents, have been recorded, though influenza itself can produce the same effects and a causal link has not been established. The respiratory system remains the site of the illness throughout.
Also known as
Used in a sentence
Tamiflu was prescribed after the patient tested positive for influenza.
Good to know
Tamiflu acts on influenza only and works by limiting the spread of virus between cells, so its measured benefit depends heavily on how soon after symptoms begin it is started.