phenelzine sulfate (fen´
lzēn´ sul´fāt),drug class: antidepressant, monoamine antioxidase inhibitor;
action: increases concentrations of endogenuous epinephrine, norepinephrine, serotonin, dopamine in storage sites in central nervous system;
use: depression when uncontrolled by other means.
phenelzine sulfate
Nardil
Pharmacologic class: MAO inhibitor
Therapeutic class: Antidepressant
Pregnancy risk category C
FDA Boxed Warning
• Drug may increase risk of suicidal thinking and behavior in children and adolescents with major depressive disorder and other psychiatric disorders. Risk must be balanced with clinical need, as depression itself increases suicide risk. With patient of any age, observe closely for clinical worsening, suicidality, and unusual behavior changes when therapy begins. Advise family and caregivers to observe patient closely and communicate with prescriber as needed.
• Drug isn't approved for use in pediatric patients.
Action
Nonselectively inhibits metabolism of MAO, an enzyme that increases accumulation of endogenous epinephrine, norepinephrine, and serotonin in CNS
Availability
Tablets: 15 mg
⊘Indications and dosages
➣ Atypical or neurotic depression
Adults: Initially, 15 mg P.O. t.i.d.; may increase rapidly to at least 60 mg/day, then 90 mg/day if needed for adequate response. Then reduce slowly to a maintenance dosage as low as 15 mg/day.
Contraindications
• Hypersensitivity to drug
• Pheochromocytoma
• Heart failure or other cardiovascular disease
• Abnormal liver function tests, history of hepatic disease
• History of headache
• Concurrent use of sympathomimetics, guanethidine, dextromethorphan, CNS depressants, buspirone, or serotonergic drugs
Precautions
Use cautiously in:
• hyperthyroidism, seizure disorders, hypotension, hypomania, diabetes mellitus, hepatic complications, myocardial ischemia
• patients switching from other MAO inhibitors
• suicidal or drug-dependent patients
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 16.
Administration
☞ If hypertensive crisis occurs, discontinue drug immediately and give phentolamine 5 mg I.V. slowly as ordered.
☞ Ask patient about other drugs he's using; MAO inhibitors can cause dangerous interactions with many drugs.
| Route | Onset | Peak | Duration |
| P.O. | Unknown | 2-6 hr | Variable |
Adverse reactions
CNS: dizziness, headache, drowsiness, hyperreflexia, hypersomnia, tremors, atigue, insomnia, palilalia, euphoria, paresthesia, ataxia, manic reaction, acute anxiety reaction, schizophrenia precipitation, shock-like coma, seizures, toxic delirium , suicidal behavior or ideation (especially in child or adolescent)
CV: orthostatic hypotension, edema, hypertensive crisis, arrhythmias
EENT: blurred vision, glaucoma, nystagmus
GI: nausea, vomiting, diarrhea, constipation, GI disturbances, epigastric or abdominal pain, dry mouth
GU: urinary retention, sexual disturbances
Hematologic: leukopenia
Hepatic: jaundice, fatal progressive necrotizing hepatocellular disease
Metabolic: hypernatremia, hypermetabolic syndrome
Musculoskeletal: muscle twitching
Skin: pruritus, rash, sweating
Other: weight changes, fever, lupus-like syndrome, edema
Interactions
Drug-drug. Amphetamines, CNS depressants, dextromethorphan, dibenzazepine derivatives, other MAO inhibitors, serotonergic agents (such as fluoxetine, paroxetine), tryptophan: hypertensive crisis, seizures, fever, diaphoresis, excitation, delirium, tremor, coma, circulatory collapse
Antidepressants, buspirone: hypertension
Antihypertensives, beta-adrenergic blockers, thiazide diuretics: increased hypotensive effect
Epinephrine, guanadrel, guanethidine, norepinephrine, reserpine, vasoconstrictors: hypertensive crisis
Insulin, oral hypoglycemics: additive hypoglycemia
Drug-diagnostic tests. Sodium, transaminases: increased levels
White blood cells: decreased count
Drug-food. Aged, pickled, fermented, or smoked foods; wine; alcohol-free wine and beer; broad bean pods; cheese (except cottage and cream cheese); excessive amounts of chocolate or caffeine; dry sausage (including hard salami, pepperoni, and Lebanon bologna); foods containing L-tryptophan (such as dairy foods, soy, poultry, and meat); liver; spoiled or improperly refrigerated, handled, or stored protein-rich foods; yeast extract; yogurt: hypertensive crisis
Drug-herbs. Ephedra (ma huang), L-tryptophan: hypertensive crisis
Drug-behaviors. Alcohol use: hypertensive crisis
Patient monitoring
• Monitor blood pressure. Drug may cause orthostatic hypotension or hypertensive crisis.
• Assess patient for symptomatic improvement.
• Monitor CBC, liver function tests, and blood glucose level before and during therapy.
• Watch for increasing depression, suicide attempt, or suicidal ideation (especially in child or adolescent).
Patient teaching
• Explain importance of taking drug exactly as prescribed.
• Tell patient to discontinue drug at least 10 days before elective surgery.
• Stress importance of avoiding alcohol, certain foods and beverages, prescription drugs, and over-the-counter preparations during and for 14 days after therapy. Ask pharmacist to provide patient with complete list of foods to avoid.
☞ Instruct patient to immediately report occipital headache, palpitations, stiff neck, nausea, sweating, dilated pupils, and photophobia (indications of hypertensive crisis).
☞ Advise patient or caregiver to immediately report increasing depression, suicide attempt, or suicidal ideation (especially in child or adolescent).
☞ Tell patient to immediately report nausea, unusual tiredness, yellowing of skin or eyes, or irregular heart beats.
• Advise patient to rise slowly to avoid dizziness.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.
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