Paracetamol might not be as safe as you think

History of paracetamol

Paracetamol, the humble, simple analgesic, was first used clinically in 1893 but did not appear commercially until 1956 in Australia [1]. Also known as acetaminophen in North America and Japan, it is the most commonly used pain-relieving medicine, partly because of its low cost and accessibility by not requiring a doctor’s prescription. Best used to reduce fever, it also has pain-relieving properties. It’s a medicine that most people have used since childhood. However, the dangers of paracetamol, like all medicines, have the potential to cause harm. The serious nature of paracetamol is often overlooked or even forgotten entirely.

Each year in Australia, there are paracetamol-related poisonings, overdoses and deaths [2]. The concern is the numbers are on the rise. Between 2007–08 and 2016–17, there was a 44 per cent increase in the number of paracetamol poisoning-related hospital admissions in Australia [2]. Nearly three-quarters of cases were female. In the same period, the age group noted with the largest increase in the number of poisonings, a 133 per cent increase, were children aged between 10–14 years [2].  A good reason to return any old or unwanted medicines back to your pharmacy for disposal. This will avoid the risk of children and pets accidentally ingesting medicines lying around the home (especially cats in which paracetamol is extremely toxic as they lack the necessary enzymes to metabolise it) [3]. Remember, medicines should never be disposed of down the drain, sink, toilet, or put in the general rubbish.

Dangers of paracetamol

The availability of paracetamol and the capacity for it to be bought in large quantities contribute to paracetamol poisonings. Additionally, people may inadvertently double up on the same type of medicine, not knowing the ingredients of their treatments. This is part of the reason the was a call to have the ingredients put on all medication packaging to help people in the community identify and understand what medicines they were taking. If you follow the directions on the back of the packaging, you won’t take any more than the daily recommended dose of four grams of paracetamol a day, avoiding potential liver damage or other potential harm. Unfortunately, many people take regular paracetamol for chronic pain syndromes & have no idea that long term use, even in moderate doses, may contribute to chronic liver damage, fatty liver & cirrhosis. Paracetamol can also be unsafe in pregnant women causing developmental disabilities, including neurological urogenital and reproductive disorders [4].

The good news

There is some good news, however. Paracetamol is effective in managing some pain conditions. A recent review of the literature investigated the efficacy of paracetamol in forty-four painful conditions. The review found that paracetamol provided pain relief for conditions of knee or hip osteoarthritis, tension-type headache (and potentially be pain-free at 2 hours), perineal pain after childbirth [5]. However, paracetamol was found with high-quality evidence to not be effective for relieving acute lower back pain, and there was no evidence or inconclusive evidence for paracetamol being beneficial in managing chronic lower back pain, endodontic surgery pain, rheumatoid arthritis and several postoperative pain conditions (e.g. thyroidectomy, spinal surgery) [5]. With proper use, paracetamol seldom causes serious side effects, at a similar frequency compared to placebo, and in general, has broad tolerability [5].

References

Prescott LF. Paracetamol: past, present, and future. American Journal of Therapeutics. 2000;7(2):143-7.
Cairns R, et al. Paracetamol poisoning-related hospital admissions and deaths in Australia, 2004-2017. Medical Journal of Australia. 2019;211(5):218-23.
Bates N, et al. Common questions in veterinary toxicology. Journal of Small Animal Practice. 2015;56(5):298-306.
Bauer AZ, et al. Paracetamol use during pregnancy – a call for precautionary action. Nature Reviews Endocrinology. 2021. DOI: 10.1038/s41574-021-00553-7. Epub ahead of print.
Abdel Shaheed C et al. The efficacy and safety of paracetamol for pain relief: an overview of systematic reviews. Medical Journal of Australia. 2021;214:324-31.

This article was written by Dr Stephanie Mathieson & Dr Ross Walker, Dr Stephanie Mathieson is a Research Fellow at the Institute for Musculoskeletal Health, University of Sydney.

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.