Study: Paracetamol No Better Than Placebo for Low Back Pain
Authors question treatment’s universal endorsement
According to a new study published in The Lancet, paracetamol — the recommended first-line analgesic for acute low back pain — does not speed recovery or reduce pain from this condition.
Researchers in Australia conducted a randomized, placebo-controlled, double-dummy, multicenter trial to determine the efficacy of paracetamol taken regularly or as-needed to improve the time to recovery from pain compared with placebo in patients with low back pain. A total of 1,652 subjects were randomly assigned to receive up to 4 weeks of regular doses of paracetamol (three times per day; equivalent to 3,990 mg of paracetamol per day); as-needed doses of paracetamol (taken when needed for pain relief; maximum of 4,000 mg of paracetamol per day); or placebo. All of the subjects received best-evidence advice and were followed for 3 months.
The study’s primary outcome was the time until recovery from low back pain, with recovery defined as a pain score of 0 or 1 (on a 0-to-10 pain scale) sustained for 7 consecutive days.
A total of 550 subjects were assigned to the regular-dose group (550 analyzed); 549 were assigned to the as-needed group (546 analyzed); and 553 were assigned to the placebo group (547 analyzed).
The median time to recovery was 17 days in the regular-dose group; 17 days in the as-needed group; and 16 days in the placebo group (regular vs. placebo hazard ratio [HR] = 0.99; as-needed vs. placebo HR = 1.05; and regular vs. as-needed HR = 1.05).
The investigators recorded no difference between treatment groups for the time to recovery (adjusted P = 0.79). Adherence to regular tablets in the as-needed group and the number of participants reporting adverse events were also similar between groups.
In view of their findings, the authors questioned the universal endorsement of paracetamol for patients with low back pain.