Drug Class Guide
SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors)
Antidepressants that raise two brain messengers instead of one, and that also help some kinds of chronic pain.
How SNRIs Work
SNRIs slow the reabsorption of both serotonin and norepinephrine. That supports mood and, through pain-control pathways in the spinal cord, can reduce some types of chronic pain. As with SSRIs, the full effect on mood usually takes several weeks.
What SNRIs Treat
SNRIs in Our Medication Guide
- DuloxetineCymbaltaAlso approved for diabetic nerve pain, fibromyalgia and chronic musculoskeletal pain.
- VenlafaxineEffexor XRDepression, generalized anxiety, social anxiety and panic disorder; can raise blood pressure at higher doses.
- DesvenlafaxinePristiqThe active form of venlafaxine; approved for depression.
- LevomilnacipranFetzimaApproved for depression.
Common Side Effects
Nausea, dry mouth, sweating, constipation, trouble sleeping and sexual side effects are common, and many ease after the first weeks. SNRIs can raise blood pressure and heart rate, so blood pressure is checked during treatment.
Important Cautions
- All antidepressants carry an FDA boxed warning about suicidal thoughts in people under 25.
- Missed doses and sudden stops can cause strong discontinuation symptoms, especially with venlafaxine.
- Duloxetine is usually avoided with heavy alcohol use or liver disease.
- Combining with other serotonin-raising drugs can cause serotonin syndrome.
Common Questions About SNRIs
Are SNRIs better than SSRIs for pain?
For some kinds of pain, yes. Duloxetine is FDA-approved for diabetic nerve pain, fibromyalgia and chronic musculoskeletal pain, which SSRIs are not. For depression alone, SNRIs and SSRIs work about equally well.
Can SNRIs raise blood pressure?
They can, especially venlafaxine at higher doses, because norepinephrine tightens blood vessels. The rise is usually small, but your blood pressure should be checked after starting and after dose increases.
Why do I feel dizzy when I miss a dose of venlafaxine?
Venlafaxine leaves the body quickly, so even one missed dose can cause discontinuation symptoms such as dizziness, nausea and brief electric-shock sensations. Taking it at the same time daily helps. If you want to stop, your doctor will taper it slowly.
This guide is general information, not a substitute for advice about your own medicines. Do not start, stop or switch a medication without talking with your doctor. Questions about a prescription? Our internal medicine team can help.
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Trusted Resources for SNRIs
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