Paracetamol: a friend or a villain?
In general, when people think of paracetamol they think of a “friendly” medication that can be used without any possible problems and it is beyond doubt a very useful medication.
As a matter of fact, almost everyone carries some … just in case. Funnily enough, it is a general belief that it is good for everything and harmless. Unfortunately, this is not the case.
Whilst generally safe for using at recommended dosages, even small overdoses can be fatal and people can die as a result of taking even a small dose of paracetamol.
Even so, compared to other over-the-counter pain relief medication it may be less toxic when used chronically at recommended doses, but it is significantly more toxic in overdose.
Paracetamol, also known as acetaminophen, is a widely used over-the-counter pain reliever (analgesic) and fever reducer (antipyretic).
It is a mild analgesic, commonly used for the relief of headaches and other minor aches and pains. But it is also a major ingredient in numerous cold and flu remedies and when combined with stronger analgesics like the opioid ones, it can also be used in the management of more severe pain such as post-surgical pain and in advanced cancer patients for palliative care as well.
Many people use paracetamol for inflammatory pain, although it only has a weak anti-inflammatory activity. People feel it works, as a result of the analgesic effect, but it is not treating the inflammation that is the base of the problem very efficiently.
While it has analgesic and antipyretic properties comparable to those of aspirin, the anti-inflammatory activity is limited as it has no direct effect at the site of inflammation, but instead acts in the central nervous system.
After oral administration, it is rapidly absorbed by the gastrointestinal tract.
Acute paracetamol overdose can cause potentially fatal liver damage. Things get much worse when combined with alcoholic drinks, and in chronic alcoholics or patients with liver damage.
Paracetamol is metabolised primarily in the liver into toxic and non-toxic products.
Some final products are inactive, non-toxic, and eventually excreted by the kidneys.
However, there is an intermediate product that is toxic and is considered to be responsible for liver problems, like acute liver failure, a killer clinical condition. It is even more dangerous for some people who have ongoing liver problems and for those born with sensitivity to paracetamol where it can progressively damage the liver function.
Small children seem to tolerate the toxicity of high dosages better than older ones and adults.
When used in adequate dosage it can be used safely for pregnant and breast-feeding women.
World demand for paracetamol was estimated at over 35,000 tonnes per year.
The efficacy of paracetamol by itself in children with fever has been questioned and showed to be less effective than ibuprofen.
Paracetamol has analgesic properties comparable to those of aspirin, while its anti-inflammatory effects are weaker. It is better tolerated than aspirin in patients in whom there is excessive stomach acid secretion or prolongation of bleeding time.
In some cases, the standard over-the-counter dose of ibuprofen gives greater pain relief than the standard dose of paracetamol.
In recommended doses and for a limited course of treatment, the adverse side effects of paracetamol are mild to non-existent.
Paracetamol toxicity is the foremost cause of acute liver failure in the Western World.
Compared to ibuprofen whose side effects may include diarrhoea, vomiting and abdominal pain, it has fewer adverse gastrointestinal effects.
It was not until 1887 that a clinical pharmacologist tried paracetamol on patients.
Paracetamol was first marketed in the United States in 1950 and went on sale in the United Kingdom in 1956 under the trade name Panadol.
Panadol was originally available only by prescription, for the relief of pain and fever, and was advertised as being “gentle to the stomach”, since other analgesic agents of the time contained aspirin, a known stomach irritant.
In terms of quantity, according to the Portuguese National Pharmacy Institute, paracetamol is the most sold medicine, but nothing is perfect and the problem starts when taken in excess.
We all know that there are no medicines that are totally innocent and, like in everything else, too much can never be good.
It is our own responsibility if paracetamol turns … from a friend into a villain!
Best health wishes,
Dr. Maria Alice
Dr Maria Alice is a consultant in General and Family Medicine. General Manager/Medical Director – Luzdoc International Medical Service / Medilagos. Medical Director – Grupo Hospital Particular do Algarve