A new study assessing paracetamol (acetaminophen) for lower back pain has reported no difference between the treatment groups and placebo group, calling into question the current recommendations of paracetamol as first line therapy for lower back pain.
Lower back pain is the leading cause of disability worldwide. Current clinical guidelines recommend treatment with paracetamol as first-line therapy. Although these are the current recommendations, there are no studies that provide a basis for the use of paracetamol (acetaminophen) for lower back pain. Therefore, a recent study aimed to assess the effectiveness of paracetamol as a first line treatment for lower back pain. This study was conducted across 235 primary care centres in Australia between 2009 and 2013.
Participants were only included in the study if they were suffering from a new episode of lower back pain (<6 weeks), and had previously had one month of no reported lower back pain. The patients were randomly assigned to one of three groups, in a 1:1:1 ratio. The first group was assigned 3 doses per day of paracetamol (equivalent to 3990mg paracetamol per day), the second group was assigned paracetamol on an ‘as-needed’ basis (maximum 4000mg paracetamol per day, to take only when needed, for pain relief), and the third group was a placebo group. The participants were instructed to take the medicine either until they had recovered from their symptoms, or for four weeks (whichever came first). In addition, participants were told to remain active, and avoid bed rest for the duration of the study. The participants were followed up at 1, 2, 4, 8 and 12 weeks. A total of 550 participants were recruited to the three times daily treatment group, 546 to the ‘as-needed’ group, and 547 to the placebo group.
The primary outcome measure of the study was time to recovery from the lower back pain. Recovery was assessed using a pain score between 0-10. Participants had to have a pain score between 0-1 for seven consecutive days to have been considered recovered.
The study reported no difference in recovery time between groups, with a median time to recovery of 17 days for both treatment groups, and 16 days for the placebo group. This recovery was maintained by 83-85% in all groups for the 12 week follow up period. In addition, the study reported that paracetamol did not have a statistically significant effect on short term pain levels, disability, function, sleep quality, or quality of life.
While the findings of the study suggest that paracetamol is not an effective treatment for lower back pain, the severity of lower back pain in the studied group was not enough to cause the patients to have missed any work days. This study does not address more severe lower back pain, or any potentially beneficial effects paracetamol could have in these cases.
In addition, while the study does call into question current recommendations of treatment for patients with lower back pain, the authors of the study do not suggest any changes be made before additional follow up studies are conducted.
Williams CM, Maher CG, Latimer J, McLachlan AJ, Hancock MJ, Day RO, Lin CW.“Efficacy of paracetamol for acute low-back pain: a double-blind, randomised controlled trial.”Lancet.2014 Jul 23. pii: S0140-6736(14)60805-9. doi: 10.1016/S0140-6736(14)60805-9.
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Written by Deborah Tallarigo, PhD