There are only four MAOIs approved in the United States, which makes memorization straightforward once you have the right mental hooks. The drugs are phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), and selegiline (Emsam). Several well-known mnemonics can lock these into memory, along with the key facts about dietary restrictions and drug interactions that exams love to test.
The Core Mnemonic: PIT Stop
The most popular mnemonic uses the first letter of each generic name to spell a short phrase. Phenelzine, Isocarboxazid, Tranylcypromine, and Selegiline give you PITS. You can remember this as “taking a PIT Stop” before eating, since MAOI users need to pause and check whether a food contains tyramine before consuming it. The dietary restriction is the single most tested fact about this drug class, so tying the mnemonic directly to it reinforces both pieces of information at once.
Remembering Brand Names
Brand names are trickier, but pairing each one with a short association helps:
- Phenelzine = Nardil. Think “Nard-eel,” a slippery eel you can’t nail down, just like the side effect profile of MAOIs.
- Tranylcypromine = Parnate. “Par-nate” sounds like “partner.” Tranylcypromine is your study partner for depression.
- Isocarboxazid = Marplan. “Mar-plan” sounds like “my plan.” Your plan is to remember all four.
- Selegiline = Emsam. Emsam is a skin patch, and “Emsam” sounds like “M-SAM,” as in “stamp.” You stamp the patch on your skin.
If wordplay doesn’t stick for you, focus on alphabetical pairing: the brand names in alphabetical order (Emsam, Marplan, Nardil, Parnate) match the generic names in alphabetical order (Isocarboxazid doesn’t match here, so this trick is imperfect). A more reliable approach is simply drilling flashcards for the four pairs, since the list is short enough to memorize by brute repetition in one study session.
Which MAOI Does What
Exams often ask which MAOIs treat which conditions. Here’s the breakdown. Isocarboxazid and tranylcypromine are approved for major depressive disorder. Phenelzine covers treatment-resistant depression, panic disorder, and social anxiety disorder, making it the broadest of the group. Selegiline is the outlier: it treats major depressive disorder but is also used as an add-on therapy in Parkinson’s disease.
The Parkinson’s connection is the key to remembering selegiline’s unique role. Selegiline at low doses preferentially blocks the form of the enzyme (MAO-B) that breaks down dopamine. Since Parkinson’s involves dopamine loss, selegiline’s selectivity for dopamine makes it a natural fit. The other three MAOIs are nonselective, blocking both forms of the enzyme and raising levels of serotonin, norepinephrine, and dopamine together. A quick memory cue: “Selegiline is Selective for MAO-B, and B is for Brain dopamine in Parkinson’s.”
The Cheese Effect and Tyramine
The reason MAOIs are so heavily tested is the tyramine interaction, often called the “cheese effect.” Tyramine is a compound that builds up naturally in aged, fermented, smoked, and pickled foods. Normally your body breaks tyramine down easily. When MAOIs block that breakdown, tyramine accumulates and forces a dangerous spike in blood pressure called a hypertensive crisis.
To remember which foods are restricted, use the mnemonic SAFE CATS: Smoked meats and fish, Aged cheeses (cheddar, parmesan, camembert, stilton, gouda), Fermented foods (sauerkraut, kimchi, miso, tempeh, soy sauce), Expired or overripe foods, Cured and dried meats (salami, pepperoni, jerky), Alcoholic beverages that are unpasteurized or home-brewed, Tapped-out dairy (buttermilk, unpasteurized milk), Spreads like Vegemite and Marmite. The common thread is that aging and fermentation create tyramine, so if a food has been sitting around developing flavor, it’s likely off-limits.
Dangerous Drug Combinations
Beyond food, two categories of medications are dangerous with MAOIs. You can remember them with the phrase “Don’t DEC-orate your MAOI”: Decongestants and Serotonergic drugs.
Decongestants like phenylephrine, oxymetazoline, and pseudoephedrine (found in many cold and sinus products) can trigger the same blood pressure spike as tyramine. The cough suppressant dextromethorphan, labeled “DM” on cold medicines, is even more dangerous because it raises serotonin levels. Combining it with an MAOI can cause serotonin syndrome, a potentially life-threatening condition involving agitation, high fever, and muscle rigidity. The practical takeaway: almost any over-the-counter cold medicine is off-limits. Plain antihistamines (excluding chlorpheniramine and brompheniramine) and expectorants are generally safe.
SSRIs and other serotonin-boosting antidepressants are strictly contraindicated with MAOIs for the same serotonin syndrome risk. A 14-day washout period is required after stopping an irreversible MAOI before starting another antidepressant. Going the other direction, the washout depends on the departing drug’s half-life. Fluoxetine, for example, lingers in the body so long that a four to five week washout is needed before starting an MAOI.
Remembering Hypertensive Crisis Symptoms
If an exam asks you to identify a hypertensive crisis from tyramine, look for a sudden severe headache as the hallmark symptom. The full picture includes palpitations, chest pain, nausea, vomiting, sweating, visual changes, and confusion. A helpful mnemonic: HEAD PSVNC is hard to remember, so instead picture someone who just ate a big block of aged cheese and is now “HEAD-over-heels sick,” grabbing their head, sweating, and seeing spots. The sudden, explosive headache is the classic presentation that distinguishes this from ordinary high blood pressure.
Reversible vs. Irreversible MAOIs
One last distinction worth memorizing: all four U.S.-approved MAOIs (phenelzine, tranylcypromine, isocarboxazid, and oral selegiline at higher doses) are irreversible inhibitors. They permanently disable the enzyme, which is why effects persist for two to three weeks after stopping the drug and why the 14-day washout exists. Moclobemide, available in some countries but not the U.S., is a reversible inhibitor of MAO-A (called a RIMA). Because it lets go of the enzyme when tyramine shows up, the cheese effect is largely eliminated. The memory hook: “Moclobemide is Mild, Movable, and More forgiving.”
Putting It All Together
Here’s a single-sentence story that links the drug names to their most important fact: “You’re driving through a PIT Stop (Phenelzine, Isocarboxazid, Tranylcypromine, Selegiline) when you see a sign that says NO CHEESE, NO COLD MEDS, and WAIT 14 DAYS.” That one image captures the four drug names, the tyramine restriction, the OTC contraindication, and the washout period. Write it on a flashcard, visualize it once or twice, and the entire MAOI framework clicks into place.