Duloxetine (Cymbalta)

What Is Duloxetine?

Duloxetine (brand name Cymbalta) is a serotonin-norepinephrine reuptake inhibitor (SNRI) FDA-approved for several chronic pain conditions. While originally developed as an antidepressant, it has independent pain-relieving effects and is commonly prescribed for chronic pain even without depression.¹

FDA-Approved Pain Indications

• Fibromyalgia
• Diabetic peripheral neuropathy
• Chronic musculoskeletal pain
• Osteoarthritis
• Chronic low back pain

How It Works²

• Increases serotonin and norepinephrine
• These neurotransmitters affect pain processing
• Strengthens descending pain inhibition pathways
• Works on both mood and pain independently

Dosing

• Usually start at 30 mg once daily
• May increase to 60 mg daily
• Take with or without food
• Swallow capsule whole (don't crush)
• Takes 2-4 weeks for pain relief

Effectiveness³

• Reduces pain in 30-50% of patients
• May improve function and sleep
• Benefits mood if depression present
• Effects vary by individual
• Give adequate trial (4-8 weeks)

Common Side Effects

• Nausea (often improves)
• Dry mouth
• Drowsiness or insomnia
• Constipation
• Decreased appetite
• Sweating
• Fatigue

Serious Side Effects (Report to Doctor)

• Suicidal thoughts (especially in young adults)
• Severe skin reactions
• Liver problems
• Serotonin syndrome
• Severe blood pressure changes
• Abnormal bleeding

Important Warnings

• Don't stop abruptly—taper gradually
• Withdrawal symptoms if stopped suddenly
• Avoid alcohol (liver risk)
• Monitor blood pressure
• Black box warning for suicidal thoughts

Drug Interactions

• MAO inhibitors (dangerous—don't combine)
• Blood thinners
• Other serotonin medications
• Some pain medications
• Always review all medications with doctor

Who Should Avoid

• Uncontrolled narrow-angle glaucoma
• Liver disease
• Severe kidney problems
• Taking MAO inhibitors
• Heavy alcohol use

References

1. Skljarevski V, Desaiah D, Liu-Seifert H, et al. Efficacy and safety of duloxetine in patients with chronic low back pain. Spine. 2010;35(13):E578-E585.
2. Dhaliwal JS, Spurling BC, Molla M. Duloxetine. StatPearls Publishing; 2023.
3. Lunn MP, Hughes RA, Wiffen PJ. Duloxetine for treating painful neuropathy, chronic pain or fibromyalgia. Cochrane Database Syst Rev. 2014;1:CD007115.