Monoamine Oxidase Inhibitors (MAOIs) represent an older class of antidepressant medications. While newer antidepressants are more commonly prescribed today, MAOIs continue to be an option for managing depressive symptoms. Their effectiveness has ensured their continued, albeit specialized, role in mental health treatment.
How MAOIs Work in the Brain
MAOIs function by inhibiting monoamine oxidase (MAO), an enzyme that breaks down neurotransmitters in the brain. These neurotransmitters include serotonin, norepinephrine, and dopamine, which are involved in regulating mood, sleep, and other functions.
By blocking the MAO enzyme, MAOIs prevent the breakdown of these neurotransmitters. This leads to increased levels of serotonin, norepinephrine, and dopamine in the brain. These increased levels can help alleviate symptoms of depression.
Who Might Benefit from MAOIs
MAOIs are considered when other antidepressant treatments have not been effective. They are prescribed for individuals experiencing treatment-resistant depression, a condition where other antidepressant classes, such as selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs), have not yielded sufficient improvement.
These medications can also be particularly effective for people with atypical depression. Atypical depression is characterized by specific symptoms like mood reactivity, increased appetite or weight gain, excessive sleep, and sensitivity to rejection. For some individuals, MAOIs may also lead to a faster onset of symptom relief compared to other antidepressant options.
Critical Dietary and Medication Interactions
Dietary restrictions are important with MAOI treatment, especially regarding foods rich in tyramine. Tyramine is an amino acid found in aged, fermented, or spoiled foods. When MAOIs inhibit the enzyme that breaks down tyramine, consuming these foods can lead to a rapid and dangerous increase in blood pressure, known as a hypertensive crisis.
Foods to avoid include:
Aged cheeses (e.g., cheddar, Swiss, Parmesan, blue cheeses)
Cured meats (e.g., salami, pepperoni)
Fermented products (e.g., sauerkraut, kimchi, soy sauce)
Certain alcoholic beverages (e.g., draft beer, some red wines)
Strict adherence to a low-tyramine diet is necessary throughout MAOI treatment and for at least two weeks after discontinuing the medication.
Medication interactions are also a concern. Combining MAOIs with other antidepressants, particularly SSRIs, SNRIs, or tricyclic antidepressants (TCAs), can lead to serotonin syndrome. This condition results from dangerously high levels of serotonin in the brain, causing symptoms like anxiety, agitation, high fever, sweating, confusion, and muscle tremors. Certain pain medications, cold and flu remedies, stimulants, and herbal supplements like St. John’s wort can also interact negatively with MAOIs, increasing the risk of serotonin syndrome or hypertensive reactions. A washout period, typically around 14 days, is required when switching from an MAOI to another antidepressant or vice versa to prevent these interactions.
Common Side Effects and Monitoring
MAOIs can cause common side effects. These include dry mouth, nausea, diarrhea or constipation, and changes in sleep patterns like drowsiness or insomnia. Dizziness or lightheadedness, often due to a drop in blood pressure when standing (orthostatic hypotension), is also reported. Other effects include weight gain, muscle twitching, or a pins-and-needles sensation.
Medical supervision is important during MAOI therapy, including regular monitoring of blood pressure to detect hypertensive reactions. When beginning MAOI treatment, the dosage is increased gradually to help manage side effects. Similarly, discontinuing an MAOI requires a careful, slow tapering of the dose to avoid withdrawal symptoms, sometimes called antidepressant discontinuation syndrome, which can include flu-like symptoms, restlessness, or trouble sleeping.