Definition of MAO Inhibitors

Monoamine oxidase inhibitors, or MAOIs, are a class of prescription medications prescribed for depression. MAOIs work by blocking the monoamine oxidase enzyme, which breaks down neurotransmitters such as serotonin and dopamine. MAOIs have the potential to dangerously interact with a number of other drugs and supplements, and for this reason care must be taken when taking any other medications along with MAOIs. MAOIs can also cause hypertensive crisis when the user concurrently consumes food containing the chemical tyramine.

Indications for MAOI Prescription

• MAOIs are generally prescribed for depression and tend not to be first-line agents due to their side effects and negative interactions. MAOIs have also been shown to be effective to help quit smoking.

How MAOIs Work

• MAOIs work on a pair of enzymes known as monoamine oxidase A and B. Some MAOIs are more effective on one or the other form of the enzyme. When the monoamine oxidases are inhibited, there is reduced breakdown of neurotransmitters such as dopamine, serotonin and norepinephrine, leading to a more elevated mood.

Interactions

• MAOIs have a number of dangerous interactions, which limits their prescription. First, MAOIs can interact with a number of other prescription and nonprescription drugs and supplements, including other antidepressants, certain painkillers, and St. John's Wort. Also, those on MAOIs should avoid foods containing tyramine, as it cannot be broken down because of the action of the medication, leading to the possibility of hypertensive crisis. Foods containing tyramine include processed meats, aged cheeses, certain types of red wine, and fava beans. A recently developed MAOI skin patch avoids some of this danger.

Side Effects

• MAOIs can have many side effects. Some of the more common ones include insomnia, sexual dysfunction, lightheadedness and dizziness. There is also a risk of dependency with MAOIs, and withdrawal symptoms may be noted if the drug regimen is discontinued too quickly.

Talk to Your Doctor

• Talk to your doctor about which medications are right for your specific situation.