This page describes pharmacological agents that may have legal restrictions, side effects, and drug interactions in your jurisdiction. Information is for educational research only — consult a clinician before considering any compound.

High-risk compound

Surface here is educational only; do not use without medical supervision. Our editorial verdict is SKIP-FOR-NOW — current cost / risk / redundancy puts it below the line.

Browse

Parnate

Extensively Studied

Tranylcypromine | Irreversible non-selective MAOI | FDA-approved for treatment-resistant depression since 1961

Aliases (4)

tranylcypromine · tranylcypromine sulfate · TCP · trans-2-phenylcyclopropan-1-amine

TYPICAL DOSE

30-60 mg/day in divided doses

BID divided dosing

ROUTE

Oral (tablet)

Oral tablet

CYCLE

Indefinite chronic use; 2-week MAO regeneration…

Indefinite chronic; 2-week washout if discontinued

STORAGE

Room temp; original container

Overview

What is Parnate?

Parnate (tranylcypromine) is an FDA-approved (1961) irreversible non-selective monoamine oxidase inhibitor — the most-prescribed MAOI in modern psychiatry alongside Nardil (phenelzine). Indicated for major depressive disorder, in 2026 it is primarily used for treatment-resistant depression after multiple SSRI/SNRI failures, especially when atypical, melancholic, or anxious features are prominent. Structurally a constrained amphetamine analog (trans-2-phenylcyclopropan-1-amine), it has secondary weak amphetamine-like releasing/reuptake activity that gives it a more activating, less sedating, weight-neutral profile than phenelzine.

Key Benefits

Efficacious in treatment-resistant depression where SSRIs/SNRIs have failed; uniquely strong evidence for atypical depression (Quitkin/Liebowitz Columbia/NYSPI studies) — mood reactivity, leaden paralysis, rejection sensitivity, hypersomnia, hyperphagia. Patients who respond often describe more complete remission than on SSRIs — restored emotional range, libido, and drive without the blunting and sexual dysfunction of SSRI class. Activating profile fits anergic/atypical phenotype.

Mechanism of Action

Irreversibly inhibits both MAO-A and MAO-B via covalent suicide-inhibition of the FAD cofactor. MAO-A inhibition raises synaptic serotonin and norepinephrine and blocks gut-wall metabolism of dietary tyramine (the antidepressant mechanism AND the cheese-effect mechanism — same pathway, different consequence). MAO-B inhibition raises dopamine and PEA. Plasma half-life is short (~2-3 hours) but functional MAO inhibition persists ~2 weeks until new enzyme is synthesized. Secondary weak amphetamine-like activity (NE/DA release, reuptake inhibition, TAAR1) explains the activating character vs Nardil.

Pharmacokinetics

PeakHalf-life

Approximate curve — visual aid only, not data-precise PK

Research Indications

Most Effective

Irreversible non-selective MAO-A + MAO-B inhibition — the core action

Tranylcypromine is a cyclopropylamine "suicide inhibitor" of monoamine oxidase. The cyclopropyl ring opens during the catalytic cycle to …

Effective

Secondary amphetamine-like activity — what makes Parnate distinct from Nardil

Tranylcypromine's structural backbone is *trans*-2-phenylcyclopropylamine — a constrained amphetamine analog. Beyond MAO inhibition, it h…

Investigational

The "cheese effect" — hypertensive crisis from dietary tyramine

This is the canonical MAOI hazard. Mechanism: 1. Dietary tyramine (a trace amine in aged/fermented foods) is normally inactivated by gut …

Investigational

Serotonin syndrome — the other lethal interaction class

With MAO-A blocked, any drug that acutely raises synaptic serotonin can produce serotonin syndrome — agitation, hyperthermia, clonus, aut…

Peptide Interactions

Mood stabilizers

Synergistic

(lithium, lamotrigine, valproate) — used as MAOI augmentation in some TRD/bipolar protocols. Lithium augmentation of Parnate is an established practice with …

Atypical antipsychotics

Synergistic

(low-dose quetiapine, aripiprazole) — sometimes added cautiously for residual symptoms in TRD; not a primary stack.

Thyroid (T3/Cytomel)

Synergistic

historical MAOI augmentation strategy.

All SSRIs:

Avoid

sertraline, fluoxetine (5-week washout), paroxetine, citalopram, escitalopram, fluvoxamine — serotonin syndrome

All SNRIs:

Avoid

venlafaxine, duloxetine, desvenlafaxine, milnacipran — serotonin syndrome

All TCAs:

Avoid

amitriptyline, clomipramine (worst), imipramine, nortriptyline, desipramine — serotonin syndrome / hypertensive crisis

Other MAOIs:

Avoid

phenelzine, isocarboxazid, selegiline (especially Emsam patch tiers), rasagiline, safinamide, moclobemide, linezolid (antibiotic), methylene blue (procedural)

Bupropion (Wellbutrin):

Avoid

hypertensive crisis + seizure risk

Tramadol, meperidine (Demerol), methadone, fentanyl-class:

Avoid

serotonin syndrome / hyperpyrexia. Standard non-serotonergic opioids (morphine, oxycodone, hydromorphone) are generally OK with caution.

Dextromethorphan (DXM):

Avoid

psychosis + serotonin syndrome — avoid all DXM-containing cough syrups

MDMA, methamphetamine, cocaine, amphetamine high-dose:

Avoid

catastrophic — combined hypertensive crisis + serotonin syndrome

5-HTP, L-tryptophan high-dose:

Avoid

serotonin syndrome

Quality Indicators

✓

Pharmacy-dispensed, intact packaging

Prescription tablets in original sealed packaging from a licensed US pharmacy.

✓

Brand or established generic

Brand Parnate (SmithKline / GSK lineage) or major US generic (e.g., Concordia, Par Pharmaceutical) — both well-validated.

International / gray-market sourcing

Identity + COA risk. Self-direction is unwise given the drug-interaction and dietary surface — Parnate requires psychiatric oversight.

✗

Counterfeit / unverified source

Counterfeit psychotropics are documented; never source Parnate outside a licensed pharmacy.

What to Expect

Week 1
Tolerability and dose-response.
Week 2-4
Early effect window.
Week 4-8
Peak benefit assessment.
Week 8+
Cycle decision point.

Side Effects & Safety 11

Side Effects

1Orthostatic hypotension — postural BP drop, especially first 2-4 weeks. Counterintuitive given the drug's hypertensive-crisis liability, but common — caused by impaired sympathetic reflex. Risk: falls, syncope. Hydration + slow positional changes help.
2Insomnia if dosed PM (avoid by AM/early-PM-only dosing)
3Dry mouth
4Constipation
5Mild stimulation / agitation (Parnate-specific, more than Nardil)
6Sexual dysfunction — present but generally LESS than SSRI class. Some patients on Parnate after SSRI failure report restored sexual function on MAOI.
7Weight changes — typically weight loss or neutrality (vs phenelzine's weight gain)
8Vivid dreams / sleep disturbance
9Mild tremor
10Sweating
11Sympathomimetic-style symptoms at high doses (palpitations, mild BP elevation baseline)

When to Stop

Hypertensive crisis from tyramine ingestion or sympathomimetic drug interaction. Symptoms: severe occipital headache, sweating, palpitations, nausea, BP spike to 200-250+ systolic. Real ER event. Treated with phentolamine IV, nicardipine, or sublingual nifedipine (older protocol). This is the iconic Parnate hazard.
Serotonin syndrome from co-administration with serotonergic drugs. Can be fatal.
Hypomania/mania induction in bipolar-spectrum users. Screen carefully.
Hepatotoxicity — rare but documented, monitor LFTs at baseline + periodically. Phenelzine has higher rate; Parnate lower.
Suicidal ideation — black-box warning (class effect) for antidepressants in <25 yo.
First 2-4 weeks: orthostatic hypotension, sleep disturbance, initial activation/insomnia
Indefinite: tyramine + drug-interaction vigilance
Post-discontinuation: 2-week MAO regeneration period during which all interactions still apply