Side Effects of MAOIs
Monoamine oxidase inhibitors, or MAOIs, are a class of antidepressants first introduced in the 1960s. While MAOIs are very effective at treating depression, they also cause severe side effects. Because of these side effects, combined with the need for a restricted diet, danger of overdose and withdrawal symptoms, doctors usually only prescribe MAOIs as a last resort. MAOI drugs may be prescribed if a person’s depression has not responded to other antidepressants.
MAOI antidepressants include:
- Isocarboxazid (Marplan®)
- Phenelzine (Nardil®)
- Ranylcypromine (Parnate®).
How Do MAOI Drugs Work?
Depression is linked to low levels of three neurotransmitters known as monoamines: serotonin, norepinephrine and dopamine. After these monoamines serve their purpose, an enzyme called monoamine oxidase burns them up. MAOI inhibitors block this enzyme, leading to higher levels of monoamines in the brain. Because MAOI antidepressants regulate all three neurotransmitters associated with depression, they are more effective at treating depression than drugs that regulate serotonin alone.
MAOI Inhibitor: Dietary Restrictions
Unfortunately, monoamine oxidase also cleans up a monoamine called tyramine, which plays a role in regulating blood pressure. When monoamine oxidase is blocked, levels of tyramine can begin to build up, potentially leading to a fatal increase in blood pressure.
Complicating the problem is the fact that many foods contain tyramine, so patients who are taking MAOI drugs must follow a strict diet. The following foods should be avoided while taking an MAOI inhibitor:
- Aged foods
- Alcoholic beverages
- Alcohol-free beer or wine
- Anchovies
- Any overripe fruit
- Bananas
- Bologna, salami, pepperoni or other aged sausage
- Canned figs
- Caviar
- Cheese (except cottage cheese and cream cheese)
- Chicken liver
- Fermented foods
- Meat prepared with tenderizers, or meat that isn’t fresh
- Raisins
- Smoked or pickled fish, meat or poultry
- Soy sauce.
Other foods and beverages, such as chocolate, coffee, avocados and sauerkraut, can only be eaten in moderation.
MAOI Antidepressant Side Effects
In addition to dietary restrictions, MAOI antidepressants side effects can range from mild to severe. Because of the risk for dangerous high blood pressure and brain hemorrhages, you should stop taking MAOIs and contact a doctor immediately if you experience:
- Changes in heart rate
- Chest pains
- Light sensitivity
- Nausea
- Severe headaches
- Stiff neck
- Sweating
- Vomiting.
Fever, dizziness, rash, dark urine, slurred speech and jaundice are also cause for concern.
Milder side effects of MAOI drugs include:
- Blurred vision
- Changes in appetite
- Chills
- Constipation
- Drowsiness
- Dry mouth
- Mild headaches
- Muscle twitching during sleep
- Sexual dysfunction
- Sleeping problems
- Trembling
- Urinary problems
- Weight gain.
MAOIs also cause withdrawal symptoms once patients stop taking them. In addition, MAOI drugs pose more of an overdose danger than other antidepressants, and they often react badly when mixed with other medications. Be sure to clear any current or new medications (even over-the-counter drugs, such as antihistamines) with your doctor if you’re taking MAOI antidepressants.
Resources
Croft, H. (2010). Monoamine oxidase inhibitors. Retrieved May 9, 2010, from the Healthy Place website: www.healthyplace.com/depression/antidepressants/monoamine-oxidase-inhibitors/menu-id-68/.
Depression Guide Staff. (2005). Monoamine oxidase inhibitor. Retrieved May 9, 2010, from the Depression Guide website: www.depression-guide.com/maoi.htm.