Monoamine Oxidase Inhibitors (MOAIs)


Category: Medical Options

What is it?

Monoamine oxidase inhibitors (MAOI) are a class of powerful antidepressant drugs occasionally prescribed for the treatment of depression. MAOIs have usually been reserved as a second line of treatment in depression when other classes of antidepressant drugs have been tried unsuccessfully. MOAIs were amongst the first drugs used for PTSD patients and have been increasingly replaced by SSRIs and other newer drugs which are thought to have fewer side effects. There are several MOAIs available which have a slightly different chemical makeup and effects.

:Monoamine oxidase inhibitors include:

  • Isocarboxazid
    - trade name Marplan
  • Moclobemide
    - trade name Aurorix, Manerix, Moclodura
  • Phenelzine
    - trade name Nardil
  • Tranylcypromine
    - trade name Parnate contents 5 mg, Jatrosom contents 10 mg)
  • Nialamide
  • Iproniazid
    - trade name Marsilid, Iprozid, Ipronid, Rivivol, Propilniazida
  • Iproclozide
  • Toloxatone
  • Linezolid
    - trade name Zyvox, Zyvoxid

How does it work?

In the brain, messages are passed between nerve cells via a synapse, a small gap between the cells. Naturally occurring chemicals known as neuro-transmitters (of which monoamine is one) allow the messages to pass across that gap. It is believed that incorrect levels of monoamine in some people lead to symptoms such as depression. It is thought that MOAIs improve the level of monoamine available and thus help to normalise brain function.

Is it effective?

Much of the research on MOAIs has been done on its effectiveness in treating symptoms of depression. There is very little research evidence regarding the use of MOAI medications for the treatment of PTSD symptoms. Phenelzine is the most widely studied however no significant evidence has shown that phenelzine or the other MOAIs are effective for PTSD.

Are there any disadvantages?

There can potentially be serious side effects from the use of MOAIs. Significant interactions are known to occur with certain foods and drinks and other drugs, thus patients on MOAIs must comply with dietary restrictions to limit the intake of dietary amines (found in aged cheeses, wines, Vegemite, Marmite for example). All other drugs, including those sold over the counter, must be carefully prescribed to avoid interactions. Evidence is emerging for newer forms of MAOI drugs including those administered via skin patches, which may reduce side effects. No evidence exists for their use for PTSD patients as yet.

Where do you get it?

MOAIs can only be prescribed by registered health practitioners.

What are the evidence limitations?

The evidence base for MOIA use in PTSD is poor. The studies to date have been small and the methods of diagnosing PTSD were not reported in the reviewed literature. Therefore interpreting this evidence should be undertaken with caution.


Based on current limited evidence, MOAI medication cannot be recommended for the routine treatment of PTSD. More research is required to establish the effectiveness and safety of MOAI drugs for PTSD patients. It is important that any MOAI treatment is prescribed by a registered health professional, with appropriate assessment carried out prior to treatment as well as ongoing monitoring during the course of treatment.

Key References

Bisson, JI 2007, ‘Pharmacological treatment of post-traumatic stress disorder’, Advances in Psychiatric Treatment, vol. 13, pp. 119–126.

Cooper, J, Carty, J, Creamer, M 2005, ‘Pharmacotherapy for posttraumatic stress disorder: empirical review and clinical recommendations’, Australian and New Zealand Journal of Psychiatry, vol. 39, pp. 674–682.

Ipser, J, Seedat, S & Stein, DJ 2006, ‘Pharmacotherapy for post traumatic stress disorder - a systematic review and meta-analysis’, South African Medical Journal, vol. 96, no. 10, pp. 1088-96.

Schoenfeld, F, Marmar, C & Neylan, T 2004, ‘Current concepts in pharmacotherapy for posttraumatic stress disorder’, Psychiatric Services, vol. 55, pp. 519-531.

Southwick, SM, Yehuda, R, Giller, E 1994, ‘Use of tricyclics and monoamine oxidase inhibitors in the treatment of post traumatic stress disorder: a quantitative review’, in Catecholamine Function in Post-Traumatic Stress Disorder: Emerging Concepts, ed. MM Murburg, American Psychiatric Press, Washington DC, USA.

Stein, DJ, Ipser, JC, Seedat, S 2006, ‘Pharmacotherapy for post traumatic stress disorder (PTSD)’, Cochrane Database of Systematic Reviews 2006, Issue 1. Art. No.: CD002795.
DOI: 10.1002/14651858.CD002795.pub2.

Copyright © Centre of National Research on Disability and Rehabilitation Medicine (CONROD)