Monoamine oxidase inhibitors (MAOIs) for depression
Monoamine oxidase inhibitors (MAOIs), which were some of the first antidepressants to be developed, may be helpful for people with so-called ‘atypical’ depression, where a person’s mood may brighten up with positive events but there may be other symptoms such as oversleeping, sensitivity to rejection, and intense fatigue. The MAOIs are also used to treat so-called ‘major’ depression.
MAOIs used in Australia are phenelzine (brand name Nardil) and tranylcypromine (brand name Parnate).
How they work
Depression is believed to be associated with low levels of the brain chemicals that are involved with transmitting signals between nerve cells. The MAOI antidepressants work by stopping the breakdown of these chemicals so that more of them stay in the brain helping to transmit the signals. This is a slightly different action to tricyclics and SSRIs (selective serotonin reuptake inhibitors).
Side effects
MAOIs can have some side effects, including rapid heartbeat, dizziness and severe high blood pressure.
Diet
The most important aspect your doctor will consider when deciding to prescribe a MAOI is the need for people taking these medicines to follow a strict diet while taking them. The reason why this is necessary is because MAOIs react with an amino acid known as tyramine, which is found in many popular foods and alcoholic beverages, including chocolate, banana skins, broad bean pods, matured cheeses and red wine. The effect is that tyramine levels rise in the brain and suddenly blood pressure may go up.
So, if you consume any of these foods while taking a MAOI, your blood pressure may rise rapidly and you may get severe symptoms such as headache, nausea, vomiting, or fast heartbeat. Such a situation is a medical emergency and can be very dangerous if not treated properly. If you have a reaction after eating any of these foods, contact a doctor or hospital immediately.
Cough and cold medicines
You should also not take preparations containing pseudoephedrine (found in many cough and cold preparations that you can buy over the counter in a pharmacy or supermarket) or any similar medications while you are taking MAOIs.
Other medicines
A variety of other prescription medicines should be avoided if you are taking MAOIs, including SSRIs, opiates, certain asthma medications and some high blood pressure medicines. Your doctor or pharmacist should give you a list of all foods, drinks and medicines to avoid, and you should follow this list to the letter.
Moclobemide
There is a newer MAOI available called moclobemide (e.g. Aurorix) which does not appear to be subject to as many of the dietary restrictions as the other MAOIs. Moclobemide is used to treat major depression. It can help with symptoms of lethargy and inability to concentrate, and is generally well tolerated by people. It is often prescribed as an alternative to SSRIs.
How it works
Like the other MAOIs, moclobemide works on brain chemicals, but it is more targeted. It doesn’t inhibit the chemical which breaks down tyramine, so the tyramine still gets broken down and doesn’t build up dangerously in the brain to cause high blood pressure. This means that people taking moclobemide can generally still eat foods containing tyramine and that it is more likely that their body will break it down. To be doubly sure, moclobemide is usually taken after food. However, people taking moclobemide should still avoid cough and cold preparations that contain pseudoephedrine.
Side effects
Side effects, such as difficulty sleeping, dizziness, nausea and headache, usually go away after a while.
Last Reviewed: 07 March 2009
- 1. eMIMS Prescribing Information, June 2009
