What is the recommended dose of duloxetine (Cymbalta) for treating back pain?

Duloxetine Dosing for Back Pain

For chronic low back pain, start duloxetine at 30 mg once daily for one week, then increase to 60 mg once daily, which is the recommended therapeutic dose. 1

Starting Dose and Titration

• Begin at 30 mg once daily for the first week to minimize nausea, the most common adverse effect, allowing patients to adjust before reaching the therapeutic dose 2, 1
• Increase to 60 mg once daily after one week, which is the target therapeutic dose for chronic musculoskeletal pain including low back pain 1

Maximum Dose Considerations

• 60 mg once daily is the recommended maximum dose for chronic low back pain 1
• Higher doses (120 mg daily) provide no additional benefit and are associated with significantly higher rates of adverse effects and treatment discontinuation 3, 1, 4
• In clinical trials, patients who did not respond adequately to 60 mg daily after 7 weeks were uptitrated to 120 mg, but this did not demonstrate superior efficacy compared to continuing 60 mg 1, 4

Evidence for Efficacy

• Duloxetine 60 mg daily significantly reduces pain in chronic low back pain, with mean pain reduction of approximately 0.6-0.8 points greater than placebo on a 0-10 scale 3
• Pain relief can occur as early as week 1 and is sustained throughout treatment 1
• Approximately 49% of patients achieve ≥50% pain reduction at 12 weeks with duloxetine 60 mg compared to 35% with placebo 3
• The number needed to treat (NNT) for 50% pain reduction is approximately 5-8 3, 5

Important Caveats

• Duloxetine is FDA-approved for chronic musculoskeletal pain, which includes chronic low back pain, but the evidence base is specifically for non-neuropathic, non-radicular back pain 3, 1, 4
• Avoid use in patients with severe renal impairment (creatinine clearance <30 mL/min) or chronic liver disease/cirrhosis 1
• Common adverse effects include nausea (most common), dry mouth, fatigue, diarrhea, hyperhidrosis, dizziness, and constipation 3, 1, 4
• Approximately 14% of patients discontinue due to adverse events (compared to 6% with placebo) 4
• When discontinuing, taper gradually rather than stopping abruptly to minimize withdrawal symptoms including dizziness, headache, nausea, and paresthesia 1

Duration of Trial

• Allow 4 weeks at the target dose of 60 mg daily to adequately assess therapeutic response 3
• If inadequate response after 4 weeks at 60 mg daily, consider switching to an alternative medication rather than increasing the dose 3