Nardil Withdrawal & Tapering Guide
phenelzine
Boxed Warning
Suicidality risk in children, adolescents, and young adults under 25 during initial antidepressant treatment.
In short
Nardil (phenelzine) is an MAOI with a half-life of 11.6 hours (drug); pharmacodynamic effect on MAO persists 2-3 weeks after the last dose because the enzyme is irreversibly inhibited. Very slow taper required. Withdrawal symptoms, when they occur, usually begin 1-5 days after stopping and settle within 4-8 weeks (MAO enzyme regeneration takes ~2 weeks).
- Class
- MAOI
- Half-life
- 11.6 hours (drug); pharmacodynamic effect on MAO persists 2-3 weeks after the last dose because the enzyme is irreversibly inhibited
- Common doses
- 15mg tablets
- Withdrawal onset
- 1-5 days after stopping
- Typical resolution
- 4-8 weeks (MAO enzyme regeneration takes ~2 weeks)
Educational reference only. Dose changes are decided with the prescriber who knows your history.
Overview
Phenelzine is a non-selective irreversible monoamine oxidase inhibitor (MAOI). Effective for atypical depression, treatment-resistant depression, and panic — but rarely used today because of strict dietary restrictions and dangerous drug interactions.
15mg tablets
Tablets: 15mg
Category C
Mechanism of Action
Irreversibly binds and inactivates MAO-A and MAO-B, blocking the breakdown of serotonin, norepinephrine, dopamine, and tyramine.
Taper Notes
Very slow taper required. Even after the last dose, MAO inhibition persists for ~2 weeks. Do NOT switch directly to another antidepressant — full 14-day washout required.
Hyperbolic Tapering Guidance
MAOIs are the hardest antidepressants to discontinue safely. Plan washout windows carefully when transitioning to or from any other agent.
Summary written by TaperCommunity, informed by the Maudsley Deprescribing Guidelines (Horowitz & Taylor) and related literature — see Sources & References below. Not affiliated with or endorsed by the Maudsley.
Withdrawal Timeline
1-5 days after stopping
1-3 weeks
4-8 weeks (MAO enzyme regeneration takes ~2 weeks)
Sleep architecture and mood reactivity can take 2-3 months to renormalize
Common Withdrawal Symptoms
Interactions & Safety
Drug Interactions
- SSRIs, SNRIs, TCAs, triptans, tramadol, meperidine, dextromethorphan, St John's Wort — contraindicated (serotonin syndrome / hypertensive crisis)
- Sympathomimetics (decongestants, stimulants) — hypertensive crisis
- Other MAOIs — contraindicated
Contraindications
- Pheochromocytoma
- Concurrent use of any other MAOI, SSRI, SNRI, TCA, or serotonergic drug (washout periods 14 days, longer for fluoxetine)
- Tyramine-rich diet (requires strict patient education)
Toxicity
Hypertensive crisis with tyramine-rich foods (aged cheese, cured meats, tap beer, fermented soy, broad beans). Serotonin syndrome with serotonergic agents. Significant overdose risk.
Pharmacokinetics
ADME Profile
Hepatic.
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Other Drug Profiles
The arithmetic of a proportional reduction
The Maudsley Deprescribing Guidelines and NICE NG222 describe reducing MAOI medications by a proportion of the previous dose rather than by a fixed amount, so each cut is smaller than the last. The table shows what that arithmetic produces at 10% per step, using 15 mg only as a worked example. How large each step is, how long it is held, and whether this pattern applies at all are decisions for the person and their prescriber.
| Step | % of starting dose | Worked example (15 mg start) |
|---|---|---|
| Start | 100% | 15 mg |
| Step 1 | 90% | 13.5 mg |
| Step 2 | 81% | 12.2 mg |
| Step 3 | 73% | 10.9 mg |
| Step 4 | 66% | 9.84 mg |
| Step 5 | 59% | 8.86 mg |
| Step 6 | 53% | 7.97 mg |
| Step 7 | 48% | 7.17 mg |
| Step 8 | 43% | 6.46 mg |
This is an illustration of a published method, not a schedule for anyone. It does not account for how long you have taken Nardil, your current dose, formulation, or history. TaperCommunity does not recommend doses or dose changes; those are agreed with your prescriber.
Frequently asked questions about Nardil
What are the withdrawal symptoms of Nardil (phenelzine)?
Common withdrawal symptoms of Nardil (phenelzine) include: anxiety, agitation, pressured speech, sleep disturbance, paranoid psychosis (rare), rebound depression, akathisia. Symptom severity varies by individual, dose, and duration of use.
How should I taper off Nardil (phenelzine)?
Very slow taper required. Even after the last dose, MAO inhibition persists for ~2 weeks. Do NOT switch directly to another antidepressant — full 14-day washout required. MAOIs are the hardest antidepressants to discontinue safely. Plan washout windows carefully when transitioning to or from any other agent.
How long does Nardil withdrawal last?
Nardil withdrawal typically begins 1-5 days after stopping, peaks around 1-3 weeks, and resolves within 4-8 weeks (MAO enzyme regeneration takes ~2 weeks). Sleep architecture and mood reactivity can take 2-3 months to renormalize
Can I stop Nardil cold turkey?
Stopping Nardil abruptly is not recommended. Its half-life is 11.6 hours (drug); pharmacodynamic effect on MAO persists 2-3 weeks after the last dose because the enzyme is irreversibly inhibited, and the receptor adaptations built up during treatment do not reverse at that speed, so a sudden stop tends to produce the sharpest withdrawal. Prescribing guidance favours gradual, proportional reductions agreed with your prescriber.
How long does Nardil stay in your system?
Nardil (phenelzine) has a half-life of 11.6 hours (drug); pharmacodynamic effect on MAO persists 2-3 weeks after the last dose because the enzyme is irreversibly inhibited. As a rule of thumb, a drug is mostly cleared after about five half-lives. Withdrawal symptoms often begin before the drug has fully cleared and continue after it has, because the adaptations the brain made during treatment reverse more slowly than the drug leaves the blood.
Sources & References
Nardil (phenelzine) information on this page is sourced from peer-reviewed research, regulatory bodies, clinical guidelines, and patient-advocacy organizations.
Encyclopedic & chemical databases
Neutral, high-authority entity references.
Regulatory sources
Official prescribing information and safety notices.
Peer-reviewed research
Primary literature cited in this taper guide.
- Horowitz MA, Taylor D 2019 — Tapering of SSRI treatment to mitigate withdrawal symptoms (hyperbolic taper) (The Lancet Psychiatry)
- Davies J, Read J 2019 — A systematic review into the incidence, severity and duration of antidepressant withdrawal effects (Addictive Behaviors)
- Framer A 2021 — The patient voice: an exploration of the experience of withdrawal from antidepressants (Therapeutic Advances in Psychopharmacology)
Clinical guidelines
Evidence-based deprescribing and prescribing standards.
Deprescribing-specific resources
Clinician-facing references on tapering protocols.
- Deprescribing.org — Evidence-based deprescribing algorithms from the Bruyère Research Institute
- Royal College of Psychiatrists — Stopping antidepressants — UK clinical guidance on safely discontinuing antidepressants
Patient-advocacy & lived-experience
Long-running communities documenting withdrawal experience.
- Surviving Antidepressants — tapering forum — Long-running community archive of antidepressant taper experiences
- Inner Compass Initiative — Withdrawal Project — Peer-led resources for psychiatric drug withdrawal
- Mad in America — antidepressant withdrawal archive — Journalism and personal narratives on SSRI/SNRI discontinuation
- RxISK — adverse drug reaction reporting — Independent database of patient-reported adverse effects
TaperCommunity does not provide medical advice. Always consult a qualified prescriber before adjusting psychiatric medication.