A meta-analysis of 65 studies of NSAIDS for lower back pain, with or without sciatica, showed the drugs are more effective than placebo but roughly equivalent to acetaminophen, according to a systematic review published in the first 2008 issue of The Cochrane Library.
But NSAIDs have significantly more side effects -- mainly gastrointestinal -- than acetaminophen, with a relative risk of 1.76 (with a 95% confidence interval from 1.12 to 2.76), the researchers found.
The findings support guidelines that suggest NSAIDs be used only after acetaminophen (also known in Europe as paracetamol) has been tried, "since there are fewer side effects with paracetamol," said lead author Pepijn Roelofs, a doctoral student at Erasmus University in Rotterdam, Holland, and colleagues.
The report is an undated version of a review first published in 2002. It includes 15 new studies, the researchers said. Of the 65 evaluated studies, which enrolled 11,237 patients, 28 (or 42%) were considered high quality.
The 65 studies compared NSAIDs to placebo, acetaminophen, muscle relaxants, and other drugs, non-drug treatments, and other NSAIDs, the researchers said.
They looked at 11 studies comparing NSAIDS to placebo in acute low back pain and four in chronic pain.
For acute pain, the studies were heterogeneous, but there was enough information to conclude that NSAIDs were more effective than placebo, with a pooled relative risk for global improvement after one week of 1.19, with a 95% confidence interval from 1.07 to 1.33.
The effect sizes seen in the individual studies were also small, the researchers noted.