A new study suggests that painkillers, such as paracetamol and acetaminophen, are ineffective in reducing back pain and arthritis and also increase one's risk of liver complications. Researchers call for a review of the guidelines for recommending these conventional treatments to patients.

Paracetamol is the most recommended by international doctors as initial treatment for lower back pain and osteoarthritis. Acetaminophen, sold as Tylenol in the United States, is a popular treatment as well.

Researchers at the George Institute and the University of Sydney reviewed 13 studies and found evidence that paracetamol does not treat back pain while its effect on osteoarthritis is very minimal compared to a placebo. The painkiller is not even beneficial in reducing the patient's disability and improving the quality of life. Thus, the team concluded that the benefits do not outweigh the risks.

"World-wide, paracetamol is the most widely used over-the-counter medicine for musculoskeletal conditions so it is important to reconsider treatment recommendations given this new evidence," Gustavo Machado, study leader of the George Institute and the University of Sydney, said in a press release.

"Use of paracetamol for low back pain and osteoarthritis was also shown to be associated with higher risk of liver toxicity in patients," he added. "Patients were nearly four times more likely to have abnormal results on liver function tests compared to those taking placebo pills."

Aside from liver toxicity, the researchers cited a separate study suggesting that paracetamol is linked to increased risks of cardiovascular, gastrointestinal and renal disease among adults.

McNeil Consumer Healthcare, the maker of Tylenol, disputed the findings of the study with the clinical results of their 150 studies. Some experts also agreed that a careful review should be done before accepting the recommendation of the latest study.

"Part of the problem of comparing many trials is the benefit to an individual patient is lost," Houman Danesh, director of integrative pain management at Mount Sinai School of Medicine in New York City, told HealthDay News.

Doctors are also worried that there are no other initial drug treatments available to patients suffering from back pain and osteoarthritis. Thus, if these drugs will be pulled out, patients might rely on addictive narcotic painkillers that will put them more at risk.

The study was published in the March 31 issue of the British Medical Journal.