Thursday, April 2, 2015

Paracetamol Is Ineffective In The Treatment Of Low Back Pain

Paracetamol Is Ineffective In The Treatment Of Low Back Pain


Low back and neck pain (spinal pain) are leading causes of disability worldwide, and osteoarthritis of the hip or knee is the 11th highest contributor to global disability. Moreover, the point prevalence of spinal pain is 9.4%, and osteoarthritis affects nearly 4% of the global population.

Doctors prescribe NSAIDs

Prescription of drugs usually painkillers such as Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) is the most common approach to treatment used by doctors for spinal pain and osteoarthritis. Guidelines consistently recommend the prescription of paracetamol (acetaminophen) as the first line analgesic for these conditions. Paracetamol is used to treat inflammatory pain and it is not generally classified as an NSAID because it exhibits only weak anti-inflammatory activity (it is a weak COX inhibitor).

Paracetamol effects liver functioning

For paracetamol to shows its optimal effect one might require regular doses of up to 4000 mg/day. The amount is highly debated by the researchers, as it exposes the body to some serious side-effects, primarily in the liver functioning. Supratherapeutic doses of paracetamol can overwhelm the normal metabolic pathways and protective mechanisms in the liver and produce dangerous amounts of a toxic metabolite, N-acetyl-p-benzoquinoneimine. Moreover, working out a schedule for such a dosage will be a pain in itself. The metabolism of the body will never be able to flush paracetamol completely, adding more serious side-effects which might not even exist in literature.


The National Institute for Health and Care Excellence (NICE), currently recommends paracetamol for both lower back pain and for osteoarthritis. Their decision to favour paracetamol is based on various previous clinical studies which report small effects of paracetamol compared with placebo.

Why this study?

As researchers correctly pointed out with a single word "uncertainty" in role of paracetamol in low back and neck pain, with various findings and recommendations, it was decided to review the efficacy and safety of paracetamol in patients with spinal pain or osteoarthritis of the hip or knee by including data from placebo controlled trials only, as these represent the highest standard of evidence to inform the optimal use of drugs.


A systematic electronic search in Medline, Embase, AMED, CINAHL, Web of Science, LILACS, International Pharmaceutical Abstracts, and Cochrane Central Register of Controlled Trials from inception to 8 December 2014, yielded 5498 records, and after excluding duplicates, researchers screened 4037 titles and abstracts. Two reviewers independently assessed the risk of bias of the included studies using the Cochrane Collaboration’s tool. Consensus and a third reviewer was used to resolve any disagreement.


Researchers found that here is “high quality” evidence suggesting paracetamol has a significant but small effect in patients with hip or knee osteoarthritis compared with placebo in the short term. The small effects, less than 4 points on a 0-100 point scale, are not likely to be meaningful for clinicians or patients. “High quality” evidence shows that paracetamol is ineffective for low back pain, but researchers found no trials investigating neck pain. In case of osteoarthritis, the value was found to be -3.7 points on a 0-100 pain scale. These results therefore provide an argument to reconsider the endorsement of paracetamol in clinical practice guidelines for low back pain and hip or knee osteoarthritis.

Exercise is better way to handle such pains

One more interesting finding that exercises (such as strengthening exercise) compared with no exercise control result in large treatment effects for pain reduction on lower limb osteoarthritis.

Article citation: Machado, G. C.; et. al. Efficacy and safety of paracetamol for spinal pain and osteoarthritis: systematic review and meta-analysis of randomised placebo controlled trials. BMJ 2015, 350, h1225. DOI: