Depression and MAOIs
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Monoamine oxidase inhibitors (MAOIs) are the oldest class of antidepressant medications. In the 1950's, iproniazid, an agent used to treat tuberculosis, was discovered to be an inhibitor of MAO and was inadvertently found to produce an improvement in mood.3 They are most effective in treating atypical and melancholic types of depression. Due to the medications dangerous interactions with certain foods and health conditions, they are often used as a last method of treatment.
Effect of MAOIs on Depression
Monoamine oxidase (MAO) is an enzyme used to break down catecholamines (dopamine, norepinephrine, and serotonin) in neurons. MAOIs work by inhibiting the breakdown of these neurotransmitters, and the levels of these hormones are then increased which results in elevated mood.
Research Evidence on MAOIs
Studies have shown monoamine oxidase inhibitors (MAOIs) effectiveness in treating mild to severe depression since the 1950s. However, because of their potential lethal overdose and side effects, MOIs tend to be used for treating melancholic depression and depression that has been unresponsive to other treatments. MAOIs have been shown to reduce symptoms of mood reactivity, oversleeping, and overeating characteristic of melancholic depression.1
How to Use MAOIs
A psychiatrist will typically prescribe these brands of drugs for patients with certain types of depression.
|Drug name (Brand name)||Starting dose||Therapeutic dose|
|Phenelzine (Nardil)||15-30 mg||45-90 mg|
|Selegiline (Eldepryl)||5-10 mg||20-60 mg|
|Tranylcypromine (Parnate)||10 mg||20-40 mg|
Side Effects and Warnings
MAOIs are used mainly when other antidepressants have failed in the treatment of major depression and panic disorder.3 This partly due to the risk of hypertensive reaction (severe and sudden rise in blood pressure, potentially leading to cerebral hemorrhage or death).
MAOIs can trigger high increases in blood pressure when combined with foods containing tyramine². These include soy, cheese, chocolate, overripe fruit, pickles, fermented meat and other processed foods. Some medications including decongestants also contain high levels of tyramine so patients should ask for a complete list of prohibited foods, medicines and substances when taking a MAOI5.
Other potential side effects include dry mouth, sexual dysfunction, skin rash, and blurred vision.
MOIs are fatal in overdose. Thus, they are less commonly used in comparison to other pharmacological medications.
MAOIs can cause adverse reactions when combined with many other types of drugs, such as:
- Other types of MAOIs
- Antihypertensive drugs
When taking MAOIs, you should not eat food with a high tyramine content, such as:
- Pickled, marinated, smoked, cured, or fermented foods
- Organ meats
- Nuts and peanut butter
- Fava beans
- Canned figs
- Foods containing monosodium glutamate (MSG)
Monoamine oxidase inhibitors (MOIs) have been shown to be effective in treating severe disorders and panic attacks. They have also been recently shown to be effective in treating Parkinson’s disease.³
1 McGrath PJ, Stewart JW, Harrison W et al. (1984). Treatment of Melancholia and Tranylcypromine. American Journal of Psychiatry (141).
2 DeBaffista, C. (1997). Medical Management of Depression. Durant: EMIS, Inc.
3 Briley, M & Montgomery, S. (1998). Antidepressant Therapy: The Dawn of the Third Millennium. London: Mosby.
4 Quitkin F, Rabkin A, Klein DF. (1979). Monoamine oxidase inhibitors. Archives of General Psychiatry (36).
5 National Institute of Mental Health (2008). Depression Handbook.