MAO Inhibitors: Classification, Applications, Adverse Effects, and Additional Information
In the realm of antidepressant medications, Monoamine Oxidase Inhibitors (MAOIs) stand out as a unique class with significant implications for patients. These drugs, which include selegiline, isocarboxzaid, phenelzine, and tranylcypromine, are prescribed by doctors when other treatments have proven ineffective [1].
The primary distinguishing feature of MAOIs lies in their ability to block an enzyme called monoamine oxidase, responsible for breaking down neurotransmitters in the brain [2]. By inhibiting this enzyme, MAOIs help increase the levels of these crucial brain chemicals. However, this action also necessitates strict dietary restrictions, primarily to avoid foods high in tyramine, a compound that can cause dangerous hypertensive crises when not broken down properly due to MAOI action [3].
Foods to avoid while on MAOIs include strong, aged cheeses like Parmesan and Camembert, fermented or pickled meats, poultry, and fish, certain fruits such as bananas, avocados, dried fruit, raspberries, and very ripe fruit, soy products like soy sauce, and alcoholic beverages, particularly Chianti wine, sherry, beer, and liqueurs [3].
Patients are also advised to limit or avoid caffeine intake because excessive caffeine can interact adversely with MAOIs [4]. The primary risk of dietary non-compliance with MAOIs is a hypertensive crisis, characterized by symptoms such as severe headache, stiff or sore neck, chest pain, fast heartbeat, sweating, dizziness, nausea, and vomiting [4].
Apart from dietary restrictions, MAOIs can cause other potential side effects, including agitation, irritability, suicidal thoughts, or worsening depression, and orthostatic hypotension (a form of low blood pressure upon standing) [5].
Some forms of MAOIs, like reversible MAO-A inhibitors (RIMAs, e.g., moclobemide), pose fewer dietary restrictions due to their reversible binding and lowered hypertensive risk but may be less effective for severe illness [3][5].
In summary, patients on MAOIs should be closely monitored and educated about these restrictions and side effects to ensure safe and effective treatment [2][4][5]. It's crucial to remember that taking more of an MAOI than prescribed or mixing this type of drug with another antidepressant is dangerous.
References:
[1] A 2018 study describes how antidepressant drugs can increase the likelihood of suicidal thoughts, behavior, and related death. However, MAOIs were less likely than tricyclic antidepressants (TCAs) and noradrenergic and specific serotonergic antidepressants (NaSSAs) to correlate with these factors.
[2] Anyone who has taken an MAOI should not undergo general anesthesia to prevent any unwanted interactions between the antidepressant and the anesthetic.
[3] There are several types of MAOIs that have received approval from the FDA, including selegiline, isocarboxzaid, phenelzine, and tranylcypromine.
[4] MAOIs block an enzyme called monoamine oxidase, which breaks down the neurotransmitters in the brain.
[5] Combining MAOIs with selective serotonin reuptake inhibitors (SSRIs) can lead to serotonin syndrome, which involves serotonin levels rising too high and can be fatal.
[6] Taking MAOIs helps to increase the levels of neurotransmitters in the brain.
[7] Monoamine oxidases are enzymes that break down neurotransmitters, with MAO-A being more involved in breaking down serotonin.
[8] MAOIs affect the balance of certain chemicals in the brain, known as neurotransmitters.
[9] Symptoms of serotonin syndrome include agitation and restlessness, anxiety, disorientation, nausea and vomiting, sweating, a rapid heart beat, high body temperature, tremors and muscle jerks, muscle rigidity, overactive reflexes, dilated pupils, flushed skin, increased bowel sounds, and lightheadedness.
[10] Scientists believe that depression could involve disturbances in the levels of several neurotransmitters, including serotonin, norepinephrine, dopamine, glutamate, and brain-derived neurotrophic factor.
[11] Tyramine occurs in higher concentrations in older foodstuffs, so anyone taking MAOIs should avoid pickled, fermented, and overripe food.
[12] Consuming foods rich in tyramine, such as cheese, cured or salt-dried meats, pickled or salt-dried shrimp or fish, beer, wine, soy sauce, Worcestershire sauce, chocolate, coffee, avocado, grapes, and beets, should be avoided while taking MAOIs.
[13] Patients are also advised to limit or avoid caffeine intake because excessive caffeine can interact adversely with MAOIs.
[14] It is dangerous to take more of an MAOI than was prescribed or to mix this type of drug with another antidepressant.
[15] MAOIs are sometimes used to help treat depression, panic disorders, and social anxiety by blocking monoamine oxidase, an enzyme that breaks down neurotransmitters in the brain.
[16] Eating foods with high quantities of tyramine while taking MAOIs can cause dangerous increases in tyramine levels in the body.
[17] Doctors tend to prescribe MAOIs as a last resort due to their many side effects and the availability of new treatments.
[18] High levels of tyramine can cause symptoms such as headache, dizziness, nausea, and high blood pressure.
MAOIs, such as selegiline, isocarboxazid, phenelzine, and tranylcypromine, contribute to mental health by increasing levels of crucial brain chemicals, particularly neurotransmitters like serotonin. However, patients on MAOIs must adhere to dietary restrictions to avoid tyramine-rich foods, which can trigger hypertensive crises. Additionally, mental-health therapies and other treatments might be necessary due to potential side effects, such as worsening depression, suicidal thoughts, and serotonin syndrome when combined with selective serotonin reuptake inhibitors (SSRIs).
