Taking acetaminophen, a.k.a. paracetamol, one of the most globally recognized, widely-used painkillers for a prolonged period, increases the risk of serious complications in older folks, according to a new study. It may mean rethinking the drug’s use as a first-line treatment for chronic conditions.
Even if they haven't taken it themselves at some point in their lives, most people would be familiar with acetaminophen/paracetamol. The over-the-counter analgesic, sold as Tylenol or Panadol among other brand names, is the standard, first-line treatment for pain and fever. Having been in clinical use for more than 140 years, acetaminophen is considered to be safe.
Of course, there are always caveats. For example, taking more than the recommended daily dose of acetaminophen can result in fatal liver failure. And now, a new study led by researchers at the University of Nottingham has found that for people aged 65 and over, taking repeated doses of the drug carries additional health risks.
“Due to its perceived safety, paracetamol has long been recommended by many treatment guidelines, especially in older people who are at higher risk of drug-related complications,” said Professor Weiya Zhang from the NIHR Biomedical Research Center in the University’s School of Medicine and the study’s senior author.
In the UK, people aged 65 and over are eligible for free prescriptions from their general practitioner (GP). This enabled the researchers to examine the safety of acetaminophen use in that age group. They used data from the Clinical Practice Research Datalink (CPRD) Gold study and compared acetaminophen users with non-users for the incidence of major adverse events.
Participants were 65 or over at the commencement of the study and had registered with a UK general practitioner for at least 12 months between 1998 and 2018. In total, 180,483 acetaminophen users and 402,478 non-users were included in the study. Participants who’d been issued at least two acetaminophen prescriptions within six months – and not in combination with other analgesics like codeine – were defined as exposed to acetaminophen. This definition excluded people who used the drug occasionally for things like headaches or the ‘flu.
The researchers found that prolonged acetaminophen use was associated with an increased risk of bleeding in the lower gastrointestinal (GI) tract (36%), peptic ulcer bleeding (24%), uncomplicated peptic ulcers (20%), chronic kidney failure (19%), heart failure (9%), and high blood pressure (7%). A dose-response relationship was seen for peptic ulcer bleeding, uncomplicated ulcers, and chronic kidney failure.
There is a noteworthy limitation to the study, however.
“A significant caveat to the study is that there is no provision for recording over-the-counter prescriptions in the CPRD,” the researchers said. “This limitation was a reason to restrict the study to people aged ≥65 years, who are eligible for free prescription and therefore are less likely to purchase acetaminophen independently.”
Despite this, the researchers say that the findings have clinical relevance and may necessitate rethinking their use.
“Whilst further research is now needed to confirm our findings, given its minimal pain-relief effect, the use of paracetamol as a first-line pain killer for long-term conditions such as osteoarthritis in older people needs to be carefully considered,” said Zhang.
The study was published in the journal Arthritis Care & Research.
Source: University of Nottingham
