Drug reference

Phenelzine

MAO Inhibitor · Antidepressant

Also known as Nardil, Phenelzine sulfate

MAO InhibitorAntidepressant

CDSCO approvedSchedule H

EXCRETION

—

not curated

INTERACTIONS

12 major

incl. contraindicated

PREGNANCY

—

not curated

Top interactionssee all 12 →

SympathomimeticsContraindicatedTextbookG&G 14e
Tyramine Containing FoodsContraindicatedTextbookG&G 14e
ClomipramineContraindicatedDatabaseDDInter
FluoxetineContraindicatedDatabaseDDInter

Mechanism

Phenelzine is an irreversible monoamine oxidase (MAO) inhibitor. It blocks the principal route of degradation for monoamines, thereby increasing levels of neurotransmitters such as 5-HT (serotonin) and catecholamines. This elevation in neurotransmitter levels in the brain is thought to contribute to its antidepressant effects.

Indications

Depressive illnessmajor depression (resistant to other antidepressants)

Dosing

Adult: BY MOUTH: Initially 15 mg 3 times a day; dose may be increased if necessary after 2 weeks if response is not evident, to 15 mg 4 times a day. Doses up to 30 mg three times a day may be used in hospital patients. Once satisfactory response is achieved, reduce dose gradually to lowest suitable maintenance dose (15 mg on alternate days may be adequate).
Max dose: 90 mg/day

Pharmacokinetics

Metabolism

acetylation

Side effects

Common

Cardiovascular insufficiencyDeliriumElectrolyte imbalanceFeeling jitteryFeverGastrointestinal disorderGlaucomaHypermetabolismImpaired driving abilityMalaiseMood alteredMovement disordersMuscle tone increasedMuscle twitchingNystagmusOedemaRespiratory disordersSchizophreniaSexual dysfunctionSpeech repetitiveweight gain

Serious

Fatal progressive hepatocellular necrosis
Hypertensive crisis
Intracranial haemorrhage
Lupus-like syndrome
Neuroleptic malignant syndrome
Seizure
Shock-like coma
hypertensive crisis (with tyramine-containing foods or sympathomimetics)
serotonin syndrome (with 5HT reuptake inhibitors, tryptophan, substituted amphetamines)
hepatotoxicity

Pregnancy & lactation

Lactation

Avoid - no information available.

Drug interactions

Sympathomimetics

Contraindicated

Textbook

Potentially life-threatening elevation of blood pressure (hypertensive crisis).

Avoid concurrent use of MAOIs and medications containing sympathomimetic compounds.

Source: G&G 14e

Tyramine Containing Foods

Contraindicated

Textbook

Marked increases in blood pressure (hypertensive crisis).

Patients on MAOIs must avoid foods containing high levels of tyramine, such as soy products, dried meats and sausages, dried fruits, home-brewed and tap beers, red wine, pickled or fermented foods, and aged cheeses.

Source: G&G 14e

Clomipramine

Contraindicated

Database

Increased risk of serotonin syndrome and potentiated sympathomimetic effects.

Should not be used concurrently with MAOIs or within 14 days of stopping MAOIs.

Source: DDInter

Fluoxetine

Contraindicated

Database

Serotonin syndrome: hyperthermia, rigidity, myoclonus, autonomic instability, potentially fatal

Contraindicated. Allow 5-week washout after fluoxetine before starting MAOI (long half-life of norfluoxetine)

Source: DDInter

Sertraline

Contraindicated

Database

Serotonin syndrome: agitation, hyperthermia, rigidity, seizures, potentially fatal

Contraindicated. Allow 14-day washout between SSRI and MAOI

Source: DDInter

Tramadol

Contraindicated

Database

Serious drug interaction.

Avoid coadministration.

Source: DDInter

5ht Reuptake Inhibiting Antidepressants

Severe

Textbook

Serotonin syndrome, characterized by hyperthermia, muscle rigidity, myoclonus, tremors, autonomic instability, confusion, irritability, and agitation, which can progress to coma and death.

SSRIs should not be started until at least 14 days following discontinuation of treatment with an irreversible MAOI. For all SSRIs except fluoxetine, at least 14 days should pass prior to beginning treatment with an MAOI following the end of SSRI treatment. For fluoxetine, at least 5 weeks should pass. For venlafaxine, a 7-day interval is considered safe between ending MAOI therapy and starting venlafaxine. For duloxetine, a 5-day waiting period is needed before beginning MAOI treatment after ending duloxetine.

Source: G&G 14e

Albuterol

Severe

Textbook

Increased risk of adverse cardiovascular effects.

At least 2 weeks should elapse between the use of MAO inhibitors and administration of β2 agonists or other sympathomimetics.

Source: G&G 14e · p264

Anticholinergic Antiparkinsonian Drugs

Severe

Textbook

Delirium may occur.

Source: KDT 7e · p121