Tranylcypromine (Parnate)

What it treats

Tranylcypromine is approved by the U.S. Food and Drug Administration to treat depression, particularly depression that hasn't responded to other treatments.

Off-label uses include atypical depression, social anxiety, and treatment-resistant bipolar depression. Off-label means a purpose the label doesn't formally list even though evidence and practice support it.

How it works

Tranylcypromine blocks monoamine oxidase, or MAO, the enzyme that breaks down serotonin, norepinephrine, and dopamine (and dietary tyramine). Blocking it raises levels of these messengers in the brain.

Its block is irreversible: it permanently disables the MAO molecules it binds. New MAO takes about two weeks to regenerate, which is why diet and drug restrictions have to hold for two weeks after the last dose.

Tranylcypromine is chemically related to amphetamine, and it has a modest amphetamine-like activating quality on top of the MAO effect. That's why it tends to feel more stimulating than phenelzine.

Receptor mechanism (detail)

Tranylcypromine is an irreversible, non-selective inhibitor of MAO-A and MAO-B. It's structurally related to amphetamine and produces mild dopamine and norepinephrine release, which contributes to its activating profile. Because it inhibits MAO-A in the gut, dietary tyramine restrictions apply. Because it blocks serotonin metabolism, other serotonergic drugs risk serotonin syndrome.

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual.

Starting is 10 mg twice a day. Titration goes to 30 to 60 mg per day divided. Higher doses (up to 80 mg per day) are sometimes used in refractory cases with careful monitoring.

Safety monitoring

• Blood pressure at every visit. Both hypertensive crisis (from tyramine or sympathomimetics) and orthostatic hypotension are on the table.
• Tyramine-restricted diet. Avoid aged cheeses, cured or aged meats, tap or unpasteurized beer, sauerkraut, kimchi, soy sauce and other fermented soy products, fava beans, and overripe or spoiled foods.
• 14-day washout before starting most other antidepressants and 14 days after stopping tranylcypromine before starting them. For fluoxetine specifically, wait 5 weeks after stopping it before starting tranylcypromine.
• Avoid serotonergic drugs during and for 14 days after: SSRIs, SNRIs, tramadol, meperidine, dextromethorphan, triptans, linezolid, methylene blue, St. John's wort, MDMA.
• Suicidality in the first 4 weeks, especially under age 25 (FDA boxed warning).
• Insomnia is a common early complaint given the activating profile.

What it feels like early

The first weeks tend to follow a familiar shape.

The first days to two weeks

Dizziness on standing, dry mouth, and sleep disturbance (usually insomnia because of the activating profile) are common. Some people feel a mild stimulant-like quality.

Weeks two to six

The fuller mood effect tends to build over four to six weeks at an adequate dose. Sleep changes and weight or sexual side effects can build in over this window.

Common side effects

Common side effects include:

• Insomnia (more common than sedation).
• Dizziness on standing.
• Dry mouth.
• Constipation.
• Sexual side effects.
• Sweating.
• Mild agitation.
• Edema.

If a side effect is severe, or it isn't improving, that's a conversation to have with the prescriber rather than a reason to stop on your own.

Serious side effects and warnings

Serious problems are uncommon, but a few really matter.

Boxed warning. Like all antidepressants, tranylcypromine carries an FDA boxed warning that it can increase suicidal thoughts and behaviors in children, teenagers, and young adults under 25, especially in the first weeks of treatment or after a dose change.

• Hypertensive crisis. Tyramine-rich foods or sympathomimetic drugs (some cold medicines, ephedra, some ADHD stimulants, cocaine, amphetamine) can drive blood pressure to dangerous levels. Warning signs are severe pounding headache, chest pain, nausea and vomiting, sweating, and a racing heart. This is a medical emergency.
• Serotonin syndrome. Combining tranylcypromine with other serotonergic drugs can cause severe agitation, fever, muscle rigidity, and altered mental status. Also a medical emergency.
• Orthostatic hypotension. A drop in blood pressure on standing.
• Misuse potential. Because of the amphetamine-related structure, tranylcypromine has some abuse potential, though this is uncommon in clinical practice.

Sexual side effects

Sexual side effects (reduced desire, delayed orgasm, erectile difficulty) are common but tend to be somewhat less than with phenelzine. If they appear, they're worth raising with the prescriber.

Weight, appetite, and sleep

Tranylcypromine tends to be more weight-neutral than phenelzine, though weight gain still happens. It's more likely to disturb sleep in the direction of insomnia, so the last dose is often kept to earlier in the afternoon.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber.

Tranylcypromine comes as tablets. Starting is 10 mg twice a day, with steps up over days to weeks. The last daily dose is often kept to the early afternoon so insomnia doesn't become a bigger problem than depression. A prescriber comfortable with MAOIs will walk through the diet and drug rules in detail before the first dose.

Missed doses and interactions

If you miss a dose, take it when you remember, unless it's almost time for the next dose. Skip the missed dose and carry on. Don't take two doses to make up for one.

Interactions are extensive. Common categories:

• Do not combine with SSRIs, SNRIs, other MAOIs, tramadol, meperidine, dextromethorphan, triptans, linezolid, methylene blue, St. John's wort, MDMA, or amphetamines.
• Use with caution with sympathomimetic decongestants (pseudoephedrine, phenylephrine, over-the-counter cold medications), tyramine-rich foods, and any drug that raises blood pressure.
• Wait 14 days after stopping tranylcypromine before starting a serotonergic drug (5 weeks after fluoxetine before starting tranylcypromine).

Give every prescriber and pharmacist a full list of your medications and supplements, including over-the-counter ones. Carry a card that says you take an MAOI.

Stopping and tapering

Tranylcypromine isn't a controlled substance in the usual sense, though it has some misuse potential given the amphetamine-related structure.

The body does adjust to it, and stopping abruptly can cause discontinuation symptoms. The 14-day period after stopping is also when tyramine restrictions and drug interactions still hold, because MAO enzyme has to regenerate. A prescriber typically tapers rather than stopping suddenly.

Pregnancy and breastfeeding

This is an area where individual circumstances matter and the decision belongs with a clinician. Data in pregnancy are limited, and MAOIs are generally avoided when alternatives exist. Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber so the specific risks and benefits can be weighed for their situation.

Cost and generic availability

Tranylcypromine is available as a generic. Generic tranylcypromine contains the same active medication as Parnate and works the same way. Costs vary; some pharmacies stock it inconsistently.

Common questions

How is tranylcypromine different from phenelzine? Both are irreversible MAOIs. Tranylcypromine is more activating (its amphetamine-related structure) and tends to cause less weight gain and less sedation. Insomnia is more of an issue with tranylcypromine.

Do I still need the tyramine diet with tranylcypromine? Yes. Non-selective MAO-A inhibition is what forces the diet, and tranylcypromine is a non-selective MAOI.

Do MAOIs still work when SSRIs haven't? Yes, often. Tranylcypromine is a real option in treatment-resistant and atypical depression.

Why 14 days between MAOIs and other antidepressants? Tranylcypromine irreversibly inactivates MAO. New enzyme takes about two weeks to regenerate. During that window, combining serotonergic drugs can cause serotonin syndrome.

Is it addictive? The amphetamine-related structure means there's some misuse potential, though this is uncommon in clinical practice. Stopping should still be planned with a prescriber.

Questions to ask your prescriber

• Is my prescriber comfortable with MAOIs, or should we consider a referral?
• Can we go through the tyramine diet together, and can I get a printed list?
• Which medications and supplements do I need to avoid?
• What warning signs should send me to the emergency room?
• If we decide to stop it later, how would we do that safely, and how long do the diet rules hold after stopping?

Sources

This guide draws on current prescribing information and public health references and current as of June 8, 2026. It is reviewed for clinical accuracy and updated as guidance changes.

• U.S. Food and Drug Administration. Tranylcypromine sulfate (Parnate) prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Tranylcypromine.
• National Institute of Mental Health. Mental health medications.
• American Psychiatric Association. Practice Guideline for the Treatment of Patients with Major Depressive Disorder.
• National Institute for Health and Care Excellence (NICE). NG222, Depression in adults.