MAOIs with a Focus on Phenelzine
MAOIs with a Focus on Phenelzine
Monoamine oxidase inhibitors (MAOIs) are one of the oldest, yet most effective classes of antidepressants. They were discovered in the early 1950s when isoniazid, initially used to treat tuberculosis, was found to improve patients' mood and social activity. MAOIs work by inhibiting enzymes that break down neurotransmitters such as serotonin, norepinephrine, and dopamine, which are often low in individuals with depression. In certain cases of treatment-resistant depression, Dr. Danish utilizes MAOIs. These medications have a unique mechanism of action but can lead to potentially dangerous interactions with other medications and foods, which need to be carefully discussed.
MAOIs work by blocking the enzyme monoamine oxidase, which breaks down neurotransmitters like serotonin, dopamine, and norepinephrine. By inhibiting this enzyme, MAOIs increase the levels of these neurotransmitters in the brain, enhancing mood and alleviating depressive symptoms. This unique mechanism makes MAOIs effective for treating certain types of depression, especially when other treatments have failed.
Examples of MAOIs
Phenelzine (Nardil)
Selegiline patch (Emsam)
Tranylcypromine (Parnate)
Uses of MAOIs
MAOIs are effective in treating various mental health disorders, including:
Depression
Treatment-resistant depression
Atypical depression
Panic disorder
Social phobia
Borderline personality disorder
Bulimia
PTSD
OCD
Some MAOIs also help in managing Parkinson’s disease and migraines.
Emergency Issues with MAOIs
There are significant dietary restrictions that have to be closely followed when taking a MAOI. This is because MAOIs interfere with the breakdown of an amino acid called tyramine, which is found in certain foods and beverages. High levels of tyramine can lead to severe blood pressure increases, known as hypertensive crises. Symptoms include headache, flushing, and, in severe cases, risk of brain bleed or stroke. If these symptoms occur, seek emergency medical attention.
Foods to Avoid
To prevent hypertensive crises, avoid foods high in tyramine, such as:
Aged cheeses
Sauerkraut
Cured meats
Draft beer
Overripe fruits
Fermented soy products
Medications and Supplements to Avoid
Due to the risk of a dangerous medication interaction called Serotonin Syndrome (see Dr. Danish’s blog on Serotonin Syndrome), it is crucial to avoid certain medications and supplements while on MAOIs.
Medications to Avoid:
Pain Medications: Tramadol, meperidine, dextromethorphan, methadone
Antidepressants: SSRIs, SNRIs, TCAs, bupropion, mirtazapine, St. John's Wort
Sympathomimetic Amines: Including stimulants
Atypical Antipsychotics: Many atypical antipsychotics should be avoided (or used with significant caution) due to their tendency to increase serotonin levels, which can potentially lead to serotonin syndrome. Antipsychotics can vary significantly in their effects on serotonin receptors. Here are some of the most serotonergic antipsychotics which should be avoided (or used with high caution) when on MAOIs:
Clozapine (Clozaril)
Risperidone (Risperdal)
Olanzapine (Zyprexa)
Quetiapine (Seroquel)
Aripiprazole (Abilify)
Ziprasidone (Geodon)
Lurasidone (Latuda)
Other Medications and Supplements:
Lithium: Known to increase serotonin levels.
Serotonin-Boosting Supplements: Such as 5-HTP and St. John’s Wort.
Avoiding these medications and supplements is essential to prevent the potentially life-threatening condition of serotonin syndrome. Always consult with your healthcare provider before starting or stopping any medication or supplement.
General Side Effects
Common side effects of MAOIs include:
Dry mouth
Nausea
Diarrhea
Constipation
Drowsiness
Insomnia
Dizziness
Lightheadedness
Other Precautions
Carry identification cards or wear a wristband indicating MAOI use.
Avoid MAOIs if you have a history of seizures, epilepsy, alcoholism, angina, severe headaches, blood vessel disease, diabetes, kidney or liver disease, recent heart attack or stroke, overactive thyroid, or pheochromocytoma.
Dosing of Phenelzine
Phenelzine is typically dosed twice a day, 12 hours apart. The dosing schedule is as follows:
Day 1: 15 mg in the AM and at night
Day 5: Increase to 15 mg in the AM and 30 mg at night
Day 9: Increase to 30 mg in the AM and 30 mg at night
Day 13: Increase to 30 mg in the AM and 45 mg at night
Day 17: Increase to 45 mg in the AM and the same dose at night
Why Phenelzine?
Phenelzine is effective because it works on the "big three" neurotransmitters: dopamine, norepinephrine, and serotonin. Higher doses generally result in higher efficacy. While another MAOI, the Emsam patch, is advertised as having less interactions and side effects, this is really only true at very low doses. And Phenelzine is more efficacious than Emsam, all things being equal, and has more evidence supporting its use in treatment-resistant depression.
For more on this topic and related subjects, check out these blogs:
Serotonin Syndrome: Serotonin Syndrome is a potentially life-threatening condition resulting from an excess of serotonin in the brain, often due to medication interactions. Please read Dr. Danish’s blog on Serotonin Syndrome to learn more about this critical topic.
Dr. Danish creates these handouts based on research, but they are not meant to be 100% comprehensive. Patients are invited to discuss the ideas brought up in the document with their provider. For full lists of side effects on medications and supplements, refer to drugs.com and webmd.com, as these lists are always expanding with more research.
