Long-term opioids lack pain benefit

Opioids improved pain only during short treatment.
*Systematic review/meta-analysis of randomized trials; Level 1a.

Citation

Froentjes LS, Barrington CAM, Craig RA, et al. Impact of treatment duration on the effectiveness of opioid analgesia. Br J Gen Pract. 2026. doi:10.3399/BJGP.2025.0705

Background

Opioids are often prescribed for chronic pain, but prolonged use may increase pain sensitivity or tolerance. This review tested whether benefit fades with treatment duration.

Patients

Adults with chronic low back pain or osteoarthritis. Exclusions included cancer, postsurgical pain, sciatica, inflammatory arthritis, opioid use disorder, non-self-administered opioids, tramadol, tapentadol, and enriched-withdrawal trials.

Intervention

Self-administered opioid medicines.

Control

Placebo or opioid-minimized pain management.

Outcome

Primary: at least 30% pain improvement. Secondary: pain score (0–100; 10 points is clinically important).

Follow-up Period

Short: ≤4 weeks; intermediate: 4–12 weeks; long: ≥12 weeks.

Results

Outcome Duration Finding Meaning
Meaningful pain relief (primary) ≤4 weeks 42% more likely with opioids; number needed to treat ≈7 Clinically meaningful; moderate certainty
Meaningful pain relief (primary) 4–12 weeks NS Unclear benefit; low certainty
Meaningful pain relief (primary) ≥12 weeks NS No meaningful benefit; trend favored control
Pain score (secondary) ≤4 weeks 6.1 points lower with opioids Statistical, not clinically important
Pain score (secondary) 4–12 weeks 4.3 points lower with opioids Statistical, not clinically important
Pain score (secondary) ≥12 weeks NS No clear benefit

NS = no statistically significant difference.

Trials generally used modified intention-to-treat; missing responder data counted as nonresponse. Most controls were placebo, not full active usual care.

Limitations

Probable publication bias favored opioids. Trials varied widely in drug, dose, duration, and control. Several had unclear or high risk of bias. Short and intermediate pain-score differences were below the clinically important threshold.

Funding

Unfunded; University of Alberta in-kind support; no company funding.

Clinical Application

Avoid initiating opioids for chronic low back pain or osteoarthritis when long-term treatment is likely; reserve, if ever, for brief monitored use.