Serotonin-noradrenaline reuptake inhibitors (SNRIs) are medications that increase the levels of serotonin and noradrenaline in the body, especially in the brain, hence producing a number of characteristic effects, both therapeutic and adverse.


Many TCAs are SNRIs too, although the term SNRI is usually reserved for agents with minimal affinity towards the mAChRs, H1 and adrenergic receptors.

Medical usesEdit

The major therapeutic actions of them include pain relief (especially against neuropathic pain), antidepressant effects, anxiolytic (anti-anxiety) effects and may relieve urinary incontinence.

Side effectsEdit

Their principal side effects include: digestive complaints (like dry mouth, nausea/vomiting, diarrhoea and constipation), sexual dysfunction, headache, dizziness, urinary problems,[note 1] agitation, anxiety, insomnia, drowsiness, weight loss or gain, etc. SNRIs include: desvenlafaxine, duloxetine, levomilnacipran, milnacipran and venlafaxine.

Mechanism of actionEdit


Their half-lives are all less than or equal to 12 hours, hence twice or three times daily dosing is required, except where extended release formulations are available (like for venlafaxine and desvenlafaxine). They generally have pretty minimal effects on P450 enzymes, aside from duloxetine which is a moderate inhibitor of CYP2D6. 

External linksEdit


  1. Including reduced urination, difficulty passing urine and sometimes people will quit urinating altogether
  2. Also derived from the PDSP database
  3. Other sources include AMH, Martindale, Medscape Reference and review articles
  4. Bioavailability

Reference listEdit

  1. 1.0 1.1 Brunton, L; Chabner, B; Knollman, B (2010). Goodman and Gilman's The Pharmacological Basis of Therapeutics (12th ed.). New York, USA: McGraw-Hill Professional. ISBN 978-0-07-162442-8. 

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