Paracetamol danger from repeated minor overdose
Wednesday November 23rd, 2011
People who regularly exceed recommended doses of the common pain-killer paracetamol by small amounts create serious risks for their livers, experts warned today.
The findings come as scientists offer new hope of producing a form of the drug with fewer risks attached to it.
Dr Kenneth Simpson of the Scottish Liver Transplantation Unit, UK, and colleagues publish their work in the British Journal of Clinical Pharmacology.
So-called "staggered overdoses" can occur when people repeatedly take a little bit more paracetamol - known as acetaminophen in the USA - than they should for common pains such as stomach or muscle ache, headache or toothache, say the researchers.
"They haven't taken the sort of single-moment, one-off massive overdoses taken by people who try to commit suicide, but over time the damage builds up, and the effect can be fatal," according to Dr Simpson.
His team analysed figures on 663 patients admitted to hospital between 1992 and 2008 with paracetamol-induced liver injury. Of these, 161 had taken a staggered overdose. Often staggered overdose is difficult to diagnose because the individual seeks medical attention due to feeling unwell without an obvious cause.
"This clinical situation needs to be recognized and treated rapidly because these patients are at even greater danger than people who take single overdoses," says Dr Simpson.
People with staggered overdoses may have low blood levels of paracetamol, but they are at high risk of liver failure and death and may need urgent kidney dialysis, help with breathing, or even a liver transplant.
In the study, these patients were at a greater risk of dying than those who had taken single overdoses, particularly if their admission to hospital was delayed.
They must be "closely monitored and considered for the paracetamol antidote, N-acetylcysteine, irrespective of the concentration of paracetamol in their blood", Dr Simpson advises.
* Meanwhile researchers at King's College London revealed new findings on how paracetamol works - creating hope of developing forms of the drug with fewer risks.
They say the drug interacts with a protein called TRPA1 found on nerve cells.
Working with Lund University, Sweden, the researchers have reported their findings in Nature Communications.
Researcher Dr David Andersson said: "This is an extremely exciting finding, which unlocks the secrets of one of the most widely-used medicines, and one which could impact hugely on the development of new pain relief drugs."
Nature Communications November 22 2011
Tags: Pain Relief | Pharmaceuticals | UK News
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