Danger of staggered paracetamol overdose
24th Nov 2011
Press Association all articles by this author
Medical Observer
PEOPLE who regularly take higher than the recommended dose of paracetamol over a period of time to relieve pain could be at increased risk of dying than those who take a one-off overdose, researchers warn.
The danger arises because so-called staggered overdoses are more difficult for doctors to assess.
Researchers looked at data from 663 patients admitted to the Royal Infirmary of Edinburgh from 1992 to 2008 with liver injury caused by paracetamol.
Of those patients, a total of 161 had experienced a staggered overdose, mostly after taking the drug to relieve common ailments including headache and stomach pain.
“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,” said Dr Kenneth Simpson, from the University of Edinburgh and the Scottish Liver Transplantation Unit.
The patients who took staggered overdoses on average ingested less paracetamol than patients with a single incidence of overdose – 24 g vs 27 g.
Of the patients from both groups for who timings were available, the median time of presentation at the emergency department since overdose was 23 hours.
“On admission, these staggered overdose patients were more likely to have liver and brain problems, require kidney dialysis or help with breathing and were at a greater risk of dying than people who had taken single overdoses,” Dr Simpson said.
Measuring the level of paracetamol in blood is not a safe indicator of the patient’s health for those who have taken staggered overdoses, he said.
“Staggered overdoses or patients presenting late after an overdose need to be closely monitored and considered for the paracetamol antidote, N-acetylcysteine, irrespective of the concentration of paracetamol in their blood,” Dr Simpson said.
British Journal of Clinical Pharmacology 2011; online 23 Nov
