SNRIs – Serotonin and noradrenaline reuptake inhibitors

The serotonin and noradrenaline reuptake inhibitors (SNRIs) are a group of antidepressants, and include:

How do SNRIs work?

Serotonin and noradrenaline are neurotransmitters — chemicals that relay signals between the cells in your brain. SNRIs increase the amount of these two neurotransmitters in your brain, and this is how they are thought to improve the symptoms of depression.

How effective are SNRIs?

About 50% of people treated with antidepressants find their depression symptoms are halved.

Although all antidepressants have shown similar efficacy when tested in groups of people in clinical trials, keep in mind that individuals can find one antidepressant works better for them than another. So if the first antidepressant you try doesn’t seem to be working for you after a few weeks, talk to your doctor about switching to another. A psychological therapy, such as cognitive behavioural therapy (CBT), could also be an option.

People who should take extra care with SNRIs

Make sure you tell your doctor if you have, or have had in the past, any of the following conditions before you take one of the SNRIs listed below. You might need to take extra precautions, or another medicine might be more suitable.

Duloxetine

  • bipolar disorder
  • epilepsy, a history of seizures (fits)
  • high risk of bleeding (e.g. age over 80 or previous stomach bleeding), or taking medicines that increase the risk of gastrointestinal bleeding (regular aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs)) 
  • kidney or liver problems
  • glaucoma
  • high blood pressure
  • heart problems
  • diabetes.

Older people may need to start on a lower dose of duloxetine.

Desvenlafaxine

  • bipolar disorder
  • epilepsy, a history of seizures (fits)
  • a tendency to bleed more than normal, or you are taking a blood-thinning medicine
  • kidney or liver problems
  • glaucoma
  • high blood pressure
  • raised cholesterol or lipid levels
  • heart problems
  • low blood sodium.

Venlafaxine

  • bipolar disorder
  • epilepsy, a history of seizures (fits)
  • a tendency to bleed more than normal, or you are taking a blood thinning medicine
  • kidney or liver problems
  • glaucoma
  • high blood pressure
  • heart problems
  • raised cholesterol levels.

Get advice about the risks of taking antidepressants, directly from your doctor or from a specialist information line, if you are pregnant, breastfeeding or thinking about becoming pregnant. See Antidepressants, pregnancy and breastfeeding

Side effects of SNRIs

For side effects, see the individual medicine page:

SNRIs and alcohol

For advice about alcohol consumption, see the individual medicine pages.

SNRIs and driving or operating machinery

Be careful driving or operating machinery until you know how the SNRI affects you.

For more information

References
  • Rossi S, ed. eAMH [online]. Adelaide: Australian Medicines Handbook, 2012. www.amh.net.au. (accessed 9 February 2012).
  • Eli Lilly Australia Pty Ltd. Cymbalta consumer medicine information. October 2010 (accessed 22 March 2012).
  • Pfizer Australia Pty Ltd. Pristiq consumer medicine information. June 2011 (accessed 22 March 2012).
  • Pfizer Australia Pty Ltd. Efexor-XR consumer medicine information. May 2011 (accessed 22 March 2012).