Side effects of mianserin

The response to antidepressants is quite individual, so you may not get any of these side effects, or only one or two. Some side effects are temporary, and will go away a few weeks after you started taking this medicine. If you find any side effects troublesome, talk to your doctor about how to manage them, or about switching to another medicine.

Remember that the risk of side effects with any medicine needs to be weighed against its benefit in treating your condition. Your doctor can help you weigh up the risks and benefits of taking particular medicine. See also Is this medicine right for me?

Frequency of side effects with mianserin

Common (1% of people or more)Infrequent (between 0.1% and 1% of people)Rare (fewer than 0.1% of people)
  • Sedation
  • Dry mouth
  • Dizziness
  • Vertigo
  • Weight gain
  • Fluid retention, swelling
  • Blood disorders
  • Joint pain
  • Arthritis
  • Rash
  • Seizures (fits)
  • Restlessness and difficulty staying still
  • Dizziness on standing
  • Hypomania (unusually high energy, but not as extreme as mania)
  • Slow heart rate
  • Liver function problems and jaundice
This is not a complete list of mianserin’s side effects. See the consumer medicine information (CMI) for more information.

Mianserin and driving or operating machinery

Do not drive or operate machinery until you know how this medicine affects you.

Who can I ask about side effects?

If you’re concerned that you or someone in your care is having side effects related to a medicine, seek medical advice.

Call the NPS Medicines Line on 1300 MEDICINE (1300 633 424) to get information about your prescription, over-the-counter and complementary medicines (herbal, ‘natural’, vitamins and minerals) from a pharmacist. Your call will be answered by healthdirect Australia.

To report and discuss possible side effects, call the Adverse Medicines Events (AME) line on 1300 134 237 from anywhere in Australia (Mon–Fri, 9am–5pm).

Find out more about

If you are starting mianserin, see 10 things you should know about antidepressants.

You can also read more about depression and the options for treating it.

For more information

The consumer medicine information (CMI) for your brand of mianserin is available from our website or a pharmacist. If you have any concerns about side effects, talk to your health professional. The CMI includes:

  • How to take this medicine
  • What to do if you forget to take it
  • If you take too much (overdose)
  • Things you must and must not do while taking this medicine
  • Signs of severe reactions and what to do.
  • Rossi S, ed. eAMH [online]. Adelaide: Australian Medicines Handbook, 2012. (Accessed 9 February 2012).