A meta-analysis suggests minimal benefit and substantial adverse effects.

In a guideline from the American College of Rheumatology, the opioid tramadol is ‘conditionally recommended’ for patients with hip or knee osteoarthritis (OA), when other treatments are ineffective or contraindicated (Arthritis Rheumatol 2020; 72: 220-233). In this meta-analysis, researchers examined the efficacy of tramadol in six placebo-controlled, randomised trials that involved 3600 patients with hip or knee OA. Doses were 100, 200 or 300 mg daily, and trial durations were mostly 12 weeks.

All doses of tramadol were statistically better than placebo for pain relief, but the average difference from placebo (even for the 300 mg dose) was equivalent to less than one point on a 10-point scale and was not considered to be clinically important. Only the 300 mg dose resulted in functional improvement compared with placebo, but the effect was very small. Gastrointestinal side effects and central nervous system side effects were substantially more common with all doses of tramadol than with placebo. 

Comment: These average outcomes in clinical trials do not preclude the possibility that, in an occasional patient, tramadol will provide clinically meaningful pain relief with no adverse effects. But overall, the data do not support daily tramadol for extended treatment of hip or knee osteoarthritis. Remember that tramadol is not only an opioid-receptor agonist, but also an inhibitor of serotonin and norepinephrine reuptake; in addition to its predictable opioid-related adverse effects, serotonin syndrome and seizures have been reported with this drug.

Allan S. Brett, MD, Clinical Professor of Medicine, University of Colorado School of Medicine, Aurora, USA.

Zhang X, et al. Efficacy and safety of tramadol for knee or hip osteoarthritis: a systematic review and network meta-analysis of randomized controlled trials. Arthritis Care Res (Hoboken) 2023; 75: 158-165.

This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine, Hospital Medicine.