Patients suffering acetaminophen poisoning could be helped by a small change in the way the antidote is delivered, say scientists from the University of Edinburgh in the UK.

The study, published in The Lancet, shows that using the same antidote, acetylcysteine, over a shorter time period leads to fewer side effects.

The Food and Drug Administration (FDA) says that acetaminophen, also known as paracetamol and Tylenol, is one of the most commonly used drugs in the US. It has a good record of safety and efficacy when used according to the directions on the packaging.

However, exceeding the maximum dose can cause serious liver injury or even death. Medical News Today reported last month that the combination of acetaminophen and alcohol may increase the risk of kidney dysfunction.

The National Center for Biotechnology Information (NCBI) reported in 2006 that acetaminophen accounted for 56,000 emergency room visits and 26,000 hospitalizations. Of these, 458 people died. Worryingly, this also showed that the numbers were rising, with a near doubling of fatalities between 1997 and 2001.

And this trend is reflected in the UK, the researchers say. Acetaminophen poisoning is the most common cause of overdose in the UK, with 45,000 people needing hospital attention each year.

Conventional treatment involves giving patients acetylcysteine intravenously over a 21-hour period, starting with a large proportion of the dose given quickly. However, acetylcysteine does have side effects, including vomiting, a drop in blood pressure, flushing, rashes and difficulty in breathing.

In many instances, the vomiting is so severe that the treatment has to be interrupted, typically at the 2-hour point.

The researchers undertook a double-blind, randomized study in three UK hospitals from September 6, 2010, and December 31, 2012, to find out if side effects of acetaminophen poisoning could be reduced by delivering the antidote over a shorter, modified schedule, if antiemetic (anti-vomiting) pretreatment helped, or if both revisions improved patient outcomes.

Patients suffering acute acetaminophen overdose were randomly allocated either conventional treatment or their modified protocol with the antidote delivered over a shorter time frame, with or without the addition of the antiemetic ondansetron.

To ensure the randomization, patients on the modified protocol received an infusion of 5% dextrose during the acetylcysteine delivery phase or saline instead of the ondansetron.

Of the 217 patients involved in the trial, 108 were assigned the shorter drug administration schedule, while 109 received the standard treatment.

The results showed that only 39 of the patients on the new schedule reported vomiting, retching or the need of antiemetic rescue 2 hours into the treatment, compared with 71 in the control group.

Another positive result was that fewer patients in the trial protocol experienced anaphylactoid reactions than in the control group – 5 compared with 31.

Prof. Nick Bateman, of the University of Edinburgh’s BHF Centre for Cardiovascular Science, says:

“Our finding offers a major advance in treating paracetamol poisoning, both in terms of fewer unpleasant side effects for patients and a shorter hospital stay. We need to do more work on a larger population group to find out whether treatment over a shorter time frame is as safe as the current standard.”

The study concludes that the modified regimen successfully reduced vomiting, and there was less need to interrupt the treatment. But the researchers note that more work is needed before it replaces conventional treatment methods.