MAOIs are a class of antidepressants and include the drugs isocarboxazid, phenelzine, and tranylcypromine. These drugs are used to treat depression, although they are not first-line treatments due to their side effects and dangerous food and drug interactions. Notably, MAOIs can cause a hypertensive crisis, especially if patients consume foods containing tyramine, like wine, cheese, and processed meats. MAOIs can also cause serotonin syndrome, a life-threatening condition resulting from overload of serotonin signaling. As such, MAOIs should not be given within 14 days of taking any other serotonin-altering drug.
- Key Drugs
- Inhibits the enzyme monoamine oxidase, thus increasing norepinephrine, serotonin, dopamine, and epinephrine levels in the brain.
- Clinical Use
- Because of severe adverse reactions of drug/food interactions, MAOIs are generally only used if other medications have been proved ineffective in treatment
- Parkinson’s Disease
- Selegiline and Rasagiline only (MAO-B inhibitors)
- Side Effects and Adverse Reactions
- Hypertensive Crisis
- Extremely high blood pressure that can lead to stroke, often accompanied by symptoms such as headache, tachycardia, neck stiffness, etc.
- Avoid foods containing tyramine as eating them can lead to a hypertensive crisis
- Found in aged cheese, processed meats, wine, yogurt, pickled foods, avocados, chocolate, etc.
- Hypertensive crisis may also occur with concurrent use of vasoconstrictors and cold medications that contain phenylephrine and pseudoephedrine
- Closely monitor blood pressure and tell patient to report any signs of a hypertensive crisis
- Educate patient to consult with provider before taking over the counter medications, as MAOIs have several drug interactions
- Serotonin Syndrome
- Symptoms include agitation, restlessness, confusion, tachycardia, hypertension, muscle rigidity
- MAOIs should be withdrawn 14 days before starting an SSRI or TCA (and vice versa)
- Concurrent use with other serotonin altering medications increases risk for serotonin syndrome
- MAOIs can increase the hypoglycemic effect of insulin and oral diabetic medications
- Orthostatic hypotension
- Anticholinergic effects
- Hypertensive Crisis