Duloxetine — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Duloxetine?
Duloxetine is a serotonin-noradrenaline reuptake inhibitor (SNRI) used for depression, anxiety, neuropathic pain, and fibromyalgia. This medication is funded by Pharmac under Special Authority for depression, anxiety, and neuropathic pain.
What is Duloxetine Used For?
Used for major depressive disorder, generalised anxiety disorder, diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain.
How Does Duloxetine Work?
Inhibits reuptake of both serotonin and noradrenaline, increasing their synaptic activity. The noradrenergic component enhances descending pain modulation pathways, making duloxetine effective for neuropathic pain beyond its antidepressant action.
How to Take Duloxetine
Start at 30 mg once daily for 1 week, then 60 mg once daily. Max 120 mg/day. Take with food. Swallow capsules whole. Taper gradually when stopping to prevent discontinuation syndrome.
Common Side Effects of Duloxetine
- Nausea (very common — usually improves in 1–2 weeks)
- Dry mouth
- Dizziness
- Headache
- Fatigue
- Insomnia or somnolence
- Constipation
- Sweating
- Increased blood pressure
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Serotonin syndrome (with MAOIs or other serotonergic agents)
- Hypertensive crisis (monitor BP — particularly in hypertensive patients)
- Suicidal ideation (especially in young adults — monitor early in treatment)
- Hepatotoxicity (avoid in significant liver disease)
- Severe discontinuation syndrome if stopped abruptly
Drug Interactions
Duloxetine may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- MAOIs (contraindicated — wait 14 days after stopping MAOI)
- Other serotonergic medicines
- Warfarin (increased bleeding risk)
- Tamoxifen (duloxetine inhibits CYP2D6 — reduces tamoxifen efficacy — avoid in breast cancer)
- NSAIDs and anticoagulants (increased bleeding risk)
New Zealand Prescribing Information
Duloxetine (30 mg, 60 mg capsules — Cymbalta® and generics) is funded under Special Authority. Particularly useful for patients with co-existing depression and neuropathic pain. Women on tamoxifen for breast cancer should avoid duloxetine. Monitor blood pressure during titration.
Frequently Asked Questions
How long does nausea last on duloxetine?
Nausea is very common in the first 1–2 weeks. Taking with food helps. It usually settles significantly within 2–3 weeks as your body adjusts.
Can I stop duloxetine suddenly?
No — duloxetine must never be stopped abruptly. Discontinuation syndrome (dizziness, nausea, “electric shocks”, anxiety) can be severe. Taper over at least 2–4 weeks.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: