Phenelzine

Brand Names: Nardil, Parnate

Description

Phenelzine (Nardil) is an antidepressant or mood elevator that helps to lift severe mental depression.

Phenelzine belongs to a class of drugs, called monoamine oxidase inhibitors (MAOIs), that block certain enzymes in the brain. This action increases other chemicals in the brain that help fight depression. Phenelzine can interact with certain foods and other medicines to cause unpleasant side effects. You must know what foods and medicines to avoid (see below).

Indications and Usage

Phenelzine (Nardil) is used in the treatment of depressed patients clinically characterized as "atypical", "nonendogenous" or "neurotic". These patients often have mixed anxiety and depression and phobic or hypochondriacal features. There is less conclusive evidence of its usefulness for severely depressed patients with endogenous features.

Phenelzine (Nardil) is indicated for patients who have failed to respond to the drugs more commonly used for these conditions.

Contraindications

Known hypersensitivity to the drug, pheochromocytoma, congestive heart failure, history of liver disease or abnormal liver function tests.

Patients taking phenelzine should not be given sympathomimetic drugs (including amphetamines, cocaine, methylphenidate, dopamine, epinephrine and norepinephrine), or related compounds (including methyldopa, L-dopa, L-tryptophan, L-tyrosine and phenylalanine). Hypertensive crises during phenelzine therapy may also be caused by ingestion of foods with a high concentration of tyramine or dopamine. Therefore patients being treated with phenelzine should avoid high protein food that has undergone protein breakdown by aging, fermentation, pickling, smoking or bacterial contamination; patients should also avoid cheeses (especially aged varieties), pickled herring, beer, wine, liver, yeast extract (including brewer's yeast in large quantities), dry sausage (including Genoa salami, hard salami, pepperoni and Lebanon bologna), pods of broad beans (fava beans) and yogurt, fruits/vegetables (avocado, bananas, figs, raisins, broad beans), yeast extract, soy sauce. Excessive amounts of caffeine or chocolate can also add to hypertensive reactions.

Phenelzine should not be used in combination with dextromethorphan or with CNS depressants such as alcohol and certain narcotics. Excitation, seizures, delirium, hyperpyrexia, circulatory collapse, coma and death have been reported in patients receiving MAO inhibitor therapy, who have been given a single dose of meperidine. Phenelzine should not be administered together with or in rapid succession to other MAO inhibitors (see Table I), because Hypertensive Crises and convulsive seizures, fever, marked sweating, excitation, delirium, tremor, coma and circulatory collapse may occur.

Phenelzine should not be used in combination with buspirone HCl, since several cases of elevated blood pressure have been reported in patients taking MAO inhibitors who were then given buspirone HCl. At least 10 days should elapse between the discontinuation of phenelzine and the institution of another antidepressant or buspirone HCl, or the discontinuation of another MAO inhibitor and the institution of phenelzine therapy.

There have been reports of serious reactions (including hyperthermia, rigidity, myoclonic movements and death) when fluoxetine (Prozac) has been combined with an MAO inhibitor. Therefore, phenelzine should not be used in combination with fluoxetine (Prozac). Allow at least 5 weeks between discontinuation of fluoxetine and initiation of phenelzine, and at least 10 days between discontination of phenelzine and initiation of fluoxetine.

Patients taking phenelzine should not undergo elective surgery requiring general anesthesia. Also, they should not be given cocaine or local anesthesia containing sympathomimetic vasoconstrictors. The possible combined hypotensive effects of phenelzine and spinal anesthesia should be kept in mind. Phenelzine should be discontinued at least 10 days prior to elective surgery.

MAO inhibitors including phenelzine are contraindicated in patients receiving guanethidine or reserpine.

Warnings

The most serious reactions to phenelzine (Nardil) involve changes in blood pressure.

Hypertensive Crises:
The most important reaction associated with phenelzine administration is the occurrence of hypertensive crises, which have sometimes been fatal. These crises are characterized by some or all of the following symptoms: occipital headache which may radiate frontally, palpitation, neck stiffness or soreness, nausea, vomiting, sweating (sometimes with fever and sometimes with cold, clammy skin), dilated pupils and photophobia. Either tachycardia or bradycardia may be present and can be associated with constricting chest pain.

Note:
Intracranial bleeding has been reported in association with the increase in blood pressure.

Blood pressure should be observed frequently to detect evidence of any pressor response in patients receiving phenelzine. Therapy should be discontinued immediately upon the occurrence of palpitation or frequent headaches during therapy.

Concomitant Use with Dibenzazepine Derivative Drugs:
(amitriptyline, amitriptyline and perphenazine, amoxapine, carbamazepine, clomipramine, cyclobenzaprine, desipramine, doxepin, imipramine, maprotiline, nortriptyline, trimipramine).

Severely depressed patients unresponsive to separate adequate trials of a tricyclic antidepressant, an MAO inhibitor, and electroconvulsive therapy (ECT) may benefit from cautious concomitant administration of a tricyclic antidepressant and an MAO inhibitor. However, the risk of adverse effects must be carefully weighed against the expected benefits, and patients should be cautioned by the physician regarding the possibility of adverse drug interactions.

Phenelzine should be used with caution in combination with antihypertensive drugs, including thiazide diuretics and beta-blockers, since hypotension may result.

Children:
Phenelzine is not recommended for patients under 16 years of age since there are no controlled studies of safety in this age group.

Information for the Patient:
All patients, should be warned that certain foods, beverages and medications must be avoided while taking phenelzine, and for 2 weeks after discontinuing use.

Medications to be avoided include: 1) Cold and cough preparations (including those containing dextromethorphan) 2) Nasal decongestants (tablets, drops or spray) 3) Hay-fever medications 4) Sinus medications 5) Asthma inhalant medications 6) Antiappetite medicines 7) Weight-reducing preparations 8) L-tryptophan containing preparations.

Also, certain prescription drugs should be avoided. Therefore, patients under the care of another physician or dentist, should inform him/her they are taking phenelzine.

Patients should be warned that the use of the above foods, beverages or medicines may cause a reaction characterized by headache and other serious symptoms due to a rise in blood pressure, with the exception of dextromethorphan, which may cause reactions similar to those seen with meperidine.

Patients should be instructed to report promptly the occurrence of headache, palpitations, or other unusual symptoms.

Usage in Pregnancy & Nursing

The safe use of phenelzine during pregnancy or lactation has not been established. The potential benefit of this drug, if used during pregnancy, lactation, or in women of childbearing age, should be weighed against the possible hazard to the mother or fetus.

Precautions

Before using this drug, tell your doctor your medical history, especially of heart or circulation problems, liver or kidney disease, head trauma, pheochromocytoma (specific type of tumor), alcohol use, mental/emotional conditions, frequent or severe headaches, high blood pressure and of any allergies you may have. This drug should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

In depressed patients, the possibility of suicide should always be considered and adequate precautions taken. It is recommended that careful observation of patients undergoing phenelzine treatment should be maintained until control of depression is achieved. If necessary, additional measures (ECT, hospitalization, etc.) should be instituted.

Because the effect of phenelzine on the convulsive threshold may be variable, adequate precautions should be taken when treating epileptic patients.

Of the more severe side effects that have been reported with any consistency, hypomania has been the most common. This reaction has been limited to patients in whom disorders characterized by hyperkinetic symptoms coexist with, but are obscured by, depressive effect; hypomania usually appears as depression improves. If agitation is present, it may be increased with phenelzine. Hypomania and agitation have been reported at higher than recommended doses, or following long-term therapy.

Phenelzine (Nardil, Parnate) may cause excessive stimulation in schizophrenic patients; in manic-depressive states it may result in a swing from a depressive to a manic phase.

If you are diabetic, there is a possibility that phenelzine may affect your blood sugar. Ask your prescriber or health care professional for advice if there is any change in your blood or urine sugar tests.

You may get drowsy, dizzy or have blurred vision. Do not drive, use machinery, or do anything that needs mental alertness until you know how phenelzine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may increase dizziness or drowsiness; avoid alcoholic drinks.

BEFORE USING THIS MEDICINE: INFORM YOUR DOCTOR OR PHARMACIST of all prescription and over-the-counter medicine that you are taking.

Adverse Reactions

Side effects that you should report to your prescriber or health care professional as soon as possible: agitation •chest pain •confusion •difficulty breathing •difficulty passing urine •enlarged pupils, sensitivity of the eyes to light •fever, clammy skin, increased sweating •headache •lightheadedness or fainting spells •muscle or neck stiffness or spasm •sexual dysfunction •slow, fast, or irregular heartbeat (palpitations) •yellowing of the skin or eyes.

Other less serious side-effects are: •blurred vision •constipation •difficulty sleeping •drowsiness or dizziness •dry mouth •increased appetite; weight increase •muscle aches or pains, trembling •nausea, vomiting •swelling of the feet or legs •unusual tiredness or weakness.

These effects should subside as your body adjusts to the medication.

Overdose

Signs and Symptoms

Depending on the amount of overdosage with phenelzine, a varying and mixed clinical picture may develop, involving signs and symptoms of CNS and cardiovascular stimulation and/or depression. Signs and symptoms may be absent or minimal during the initial 12-hour period following ingestion and may develop slowly thereafter, reaching a maximum in 24 to 48 hours. Death has been reported following overdosage. Therefore, immediate hospitalization, with continuous observation and monitoring throughout this period, is essential.

Signs and symptoms of overdosage may include, alone or in combination, any of the following: drowsiness, dizziness, faintness, irritability, hyperactivity, agitation, severe headache, hallucinations, trismus, opisthotonos, convulsions and coma, rapid and irregular pulse, hypertension, hypotension and vascular collapse, precordial pain, respiratory depression and failure, hyperpyrexia, diaphoresis, and cool, clammy skin.

Dosage

Follow the directions for using this medicine provided by your doctor.
Store this medicine at room temperature, in a tighly-closed container, away from heat and light.

Additional Information: Do not share this medicine with others for whom it was not prescribed. Do not use this medicine for other health conditions. Keep this medicine out of the reach of children.

Initial Dose:
The usual starting dose is 1 tablet (15 mg) 3 times/day.

Early Phase Treatment:
Dosage should be increased to at least 60 mg/day at a fairly rapid pace consistent with patient tolerance. It may be necessary to increase dosage up to 90 mg/day to obtain sufficient MAO inhibition. Many patients do not show a clinical response until treatment at 60 mg has been continued for at least 4 weeks.

Maintenance Dose:
After maximum benefit from phenelzine (Nardil, Parnate) is achieved, dosage should be reduced slowly over several weeks. Maintenance dose may be as low as 1 tablet, 15 mg/day or every other day, and should be continued for as long as is required.

IF YOU WILL BE USING THIS MEDICINE FOR AN EXTENDED PERIOD OF TIME, be sure to obtain necessary refills before your supply runs out.

NOTE: This information is not intended to cover all possible uses, precautions, interactions, or adverse effects for this drug. If you have questions about the drug(s) you are taking, check with your health care professional.

Supplied

Each orange, biconvex glossy, sugar-coated tablet contains: Phenelzine sulfate, equivalent to phenelzine base 15 mg. Nonmedicinal ingredients: Acacia, calcium carbonate, candelilla wax, cornstarch, FD&C Yellow No. 6, gelatin, kaolin, magnesium stearate, mannitol, pharmaceutical glaze, povidone, sucrose, talc. Energy: 3.1 kJ (0.75 kcal)/tablet. Gluten-free, lactose-free, paraben-free, sodium-free, sulfite-free and tartrazine-free. Bottles of 100 and 500. Store between 15 and 30°C.

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