phenelzine sulfate at a glance
Medicine class
Irreversible, non-selective monoamine oxidase inhibitor antidepressant
Important food precaution
Tyramine-rich, aged or fermented foods can cause a dangerous rise in blood pressure and must remain restricted for 14 days after stopping.
Stopping treatment
Do not stop abruptly; withdrawal can include nausea, agitation, nightmares, psychosis or seizures.
Driving
Drowsiness, dizziness or blurred vision may impair driving and machinery use.
What is phenelzine sulfate used for?
Licensed use:
Depression described as atypical, non-endogenous or neurotic, including illness with mixed anxiety, phobic or hypochondriacal features.
Depression that has not responded to other antidepressants. Evidence is less conclusive for severe depression with endogenous features.
How does phenelzine sulfate work?
Phenelzine irreversibly blocks monoamine oxidase, an enzyme that normally breaks down chemical messengers including serotonin and noradrenaline. This increases their availability in the brain and sympathetic nervous system; enzyme activity remains inhibited after the medicine itself has cleared.
phenelzine sulfate preparations and strengths
Tablet
Route: Oral
Strengths: 15 mg
How to take phenelzine sulfate
Follow the prescription label and do not change or stop treatment without prescriber guidance.
Swallow the tablets with water; they can be taken with or without food.
Follow the supplied MAOI food and drink restrictions throughout treatment and for 14 days after stopping.
Check with a pharmacist before using any non-prescription cough, cold, allergy, slimming or stimulant product.
Keep the tablets in their original pack, protected from light and refrigerated; short periods below 25°C are permitted when unavoidable.
phenelzine sulfate side effects
Common or expected effects
- Drowsiness, dizziness, weakness, tiredness or blurred vision
- A fall in blood pressure on standing, sometimes causing faintness
- Swollen ankles or other fluid retention
- Nausea, vomiting, dry mouth or constipation
- Difficulty sleeping
- Muscle twitching or increased reflexes
- Difficulty reaching orgasm
Get urgent medical advice
- Symptoms of hypertensive crisis, particularly sudden severe headache, pounding heartbeat, stiff neck, sweating, flushing or vomiting
- Fever, rapid pulse or breathing, sweating, severe muscle stiffness, changing blood pressure or reduced consciousness
- Suicidal thoughts, marked worsening of depression or unusual behavioural change
- Seizures, severe confusion, hallucinations or mania
- Drowsiness, confusion or seizures that could indicate low blood sodium
- Withdrawal-associated psychosis or seizures after abrupt discontinuation
phenelzine sulfate in pregnancy
Phenelzine should generally not be used during pregnancy, particularly in the first and last trimesters, unless there are compelling reasons. Anyone pregnant or planning pregnancy should have treatment reviewed by the prescribing specialist and should not stop phenelzine abruptly.
phenelzine sulfate while breastfeeding
It is not known whether phenelzine passes into breast milk, and serious effects in the infant are possible. The product information advises deciding between discontinuing phenelzine and not breastfeeding; this requires an individual specialist assessment considering maternal treatment needs and the infant.
phenelzine sulfate interactions
Phenelzine has potentially serious medicine and food interactions. New prescriptions, non-prescription products and planned procedures should be checked with a pharmacist or prescriber.
SSRIs, SNRIs and other antidepressants
Combining or switching without an appropriate specialist-managed washout can cause potentially fatal serotonin syndrome or other severe reactions.
Pethidine, morphine and other strong opioid analgesics
Effects can be dangerously intensified; a fatal reaction has occurred with pethidine.
Dextromethorphan
This cough suppressant must not be combined with phenelzine because a serious central nervous system reaction may occur.
Common questions about phenelzine sulfate
Answers are fully visible for fast scanning and source review.
What is phenelzine sulfate used for?
It is licensed for selected forms of depression, particularly depression with anxiety or phobic features and illness that has not responded to other antidepressants.
Is phenelzine sulfate an MAOI?
Yes. It is an irreversible, non-selective monoamine oxidase inhibitor antidepressant.
Which foods should be avoided with phenelzine sulfate?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.