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Phenelzine

Also sold as: Nardil

Monoamine Oxidase InhibitorsPrescription OnlyGeneric Available

Related Medications

Important: Only drugs listed as "Exact Equivalents" (FDA AB-rated) are confirmed interchangeable. All other listings are for informational reference only and do NOT indicate that drugs can be substituted without a physician's explicit guidance.
Same Pharmacologic Class

These drugs share a pharmacologic classification but are NOT interchangeable. Listing here does not imply clinical equivalence. A physician must evaluate each drug individually for the patient's specific condition.

Classification: Monoamine Oxidase Inhibitors (source: RxClass/NLM)

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Drug Information

Indications & Uses

INDICATIONS AND USAGE Phenelzine Sulfate Tablets, USP has been found to be effective in 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 with severely depressed patients with endogenous features. Phenelzine Sulfate Tablets should rarely be the first antidepressant drug used. Rather, it is more suitable for use with patients who have failed to respond to the drugs more commonly used for these conditions.

Dosage & Administration

DOSAGE AND ADMINISTRATION Initial dose The usual starting dose of Phenelzine Sulfate Tablets is one tablet (15 mg) three times a day. Early phase treatment Dosage should be increased to at least 60 mg per day at a fairly rapid pace consistent with patient tolerance. It may be necessary to increase dosage up to 90 mg per 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 Sulfate Tablets is achieved, dosage should be reduced slowly over several weeks. Maintenance dose may be as low as one tablet, 15 mg, a day or every other day, and should be continued for as long as is required.

Warnings & Precautions

WARNINGS Clinical Worsening and Suicide Risk Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern, however, that antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short term placebo-controlled trials of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18–24) with major depressive disorder (MDD) and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction with antidepressants compared to placebo in adults aged 65 and older. The pooled analyses of placebo-controlled trials in children and adolescents with MDD, obsessive compulsive disorder (OCD), or other psychiatric disorders included a total of 24 short-term trials of 9 antidepressant drugs in over 4400 patients. The pooled analyses of placebo-controlled trials in adults with MDD or other psychiatric disorders included a total of 295 short-term trials (median duration of 2 months) of 11 antidepressant drugs in over 77,000 patients. There was considerable variation in risk of suicidality among drugs, but a tendency toward an increase in the younger patients for almost all drugs studied. There were differences in absolute risk of suicidality across the different indications, with the highest incidence in MDD. The risk differences (drug vs placebo), however, were relatively stable within age strata and across indications. These risk differences (drug-placebo difference in the number of cases of suicidality per 1000 patients treated) are provided in Table 1. Table 1 Age Range Drug-Placebo Difference in Number of Cases of Suicidality per 1000 Patients Treated Increases Compared to Placebo <18 14 additional cases 18–24 5 additional cases Decreases Compared to Placebo 25–64 1 fewer case ≥65 6 fewer cases No suicides occurred in any of the pediatric trials. There were suicides in the adult trials, but the number was not sufficient to reach any conclusion about drug effect on suicide. It is unknown whether the suicidality risk extends to longer-term use, i.e., beyond several months. However, there is substantial evidence from placebo-controlled maintenance trials in adults with depression that the use of antidepressants can delay the recurrence of depression. All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decreases. The following symptoms, anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, and mania, have been reported in adult and pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. Although a causal link between the emergence of such symptoms and either the worsening of depression and/or the emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality. Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse, or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression or suicidality, especially if these symptoms are severe, abrupt in onset, or were not part of the patient's presenting symptoms. Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behavior, and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to health care providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for Phenelzine Sulfate Tablets should be written for the smallest quantity of tablets consistent with good patient manag

Side Effects (Adverse Reactions)

ADVERSE REACTIONS Phenelzine Sulfate Tablets is a potent inhibitor of monoamine oxidase. Because this enzyme is widely distributed throughout the body, diverse pharmacologic effects can be expected to occur. When they occur, such effects tend to be mild or moderate in severity (see below), often subside as treatment continues, and can be minimized by adjusting dosage; rarely is it necessary to institute counteracting measures or to discontinue Phenelzine Sulfate Tablets. Common side effects include: Nervous System —Dizziness, headache, drowsiness, sleep disturbances (including insomnia and hypersomnia), fatigue, weakness, tremors, twitching, myoclonic movements, hyperreflexia. Gastrointestinal —Constipation, dry mouth, gastrointestinal disturbances, elevated serum transaminases (without accompanying signs and symptoms). Metabolic —Weight gain. Cardiovascular —Postural hypotension, edema. Genitourinary —Sexual disturbances, eg, anorgasmia and ejaculatory disturbances and impotence. Less common mild to moderate side effects (some of which have been reported in a single patient or by a single physician) include: Nervous System —Jitteriness, palilalia, euphoria, nystagmus, paresthesias. Genitourinary —Urinary retention. Metabolic —Hypernatremia. Dermatologic —Pruritus, skin rash, sweating. Special Senses —Blurred vision, angle-closure glaucoma. Although reported less frequently, and sometimes only once, additional severe side effects include: Nervous System —Ataxia, shock-like coma, toxic delirium, manic reaction, convulsions, acute anxiety reaction, precipitation of schizophrenia, transient respiratory and cardiovascular depression following ECT. Gastrointestinal —To date, fatal progressive necrotizing hepatocellular damage has been reported in very few patients. Reversible jaundice. Hematologic —Leukopenia. Immunologic —Lupus-like syndrome Metabolic —Hypermetabolic syndrome (which may include, but is not limited to, hyperpyrexia, tachycardia, tachypnea, muscular rigidity, elevated CK levels, metabolic acidosis, hypoxia, coma and may resemble an overdose). Respiratory —Edema of the glottis. General —Fever associated with increased muscle tone. Withdrawal may be associated with nausea, vomiting, and malaise. An uncommon withdrawal syndrome following abrupt withdrawal of Phenelzine Sulfate Tablets has been infrequently reported. Signs and symptoms of this syndrome generally commence 24 to 72 hours after drug discontinuation and may range from vivid nightmares with agitation to frank psychosis and convulsions. This syndrome generally responds to reinstitution of low-dose Phenelzine Sulfate Tablets therapy followed by cautious downward titration and discontinuation.

Drug Interactions

Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions. Because Phenelzine Sulfate Tablets is a monoamine oxidase (MAO) inhibitor, Phenelzine Sulfate Tablets should not be used concomitantly with a serotoninergic agent (See CONTRAINDICATIONS ). Administration of guanethidine to patients receiving an MAO inhibitor can produce moderate to severe hypertension due to release of catecholamines. At least two weeks should elapse between withdrawal of the MAO inhibitor and the initiation of guanethidine. (see CONTRAINDICATIONS ) Geriatric Use Clinical studies of Phenelzine Sulfate Tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Contraindications

CONTRAINDICATIONS Phenelzine Sulfate Tablets should not be used in patients who are hypersensitive to the drug or its ingredients, with pheochromocytoma, congestive heart failure, severe renal impairment or renal disease, a history of liver disease, or abnormal liver function tests. The potentiation of sympathomimetic substances and related compounds by MAO inhibitors may result in hypertensive crises (see WARNINGS ). Therefore, patients being treated with Phenelzine Sulfate Tablets should not take 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 Sulfate Tablets therapy may also be caused by the ingestion of foods with a high concentration of tyramine or dopamine. Therefore, patients being treated with Phenelzine Sulfate Tablets 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. Excessive amounts of caffeine and chocolate may also cause hypertensive reactions. Phenelzine Sulfate Tablets 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 MAOI therapy who have been given a single dose of meperidine. Phenelzine Sulfate Tablets should not be administered together with or in rapid succession to other MAO inhibitors because HYPERTENSIVE CRISES and convulsive seizures, fever, marked sweating, excitation, delirium, tremor, coma, and circulatory collapse may occur. Concomitant use with meperidine is contraindicated (see WARNINGS ). A List of MAO Inhibitors by Generic Name Follows: pargyline hydrochloride pargyline hydrochloride and methylclothiazide furazolidone isocarboxazid procarbazine tranylcypromine Phenelzine Sulfate Tablets should also 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 14 days should elapse between the discontinuation of Phenelzine Sulfate Tablets and the institution of another antidepressant or buspirone HCl, or the discontinuation of another MAO inhibitor and the institution of Phenelzine Sulfate Tablets. There have been reports of serious reactions (including hyperthermia, rigidity, myoclonic movements and death) when serotoninergic drugs (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) have been combined with an MAO inhibitor. Therefore, the concomitant use of Phenelzine Sulfate Tablets with serotoninergic agents is contraindicated (see PRECAUTIONS Drug Interactions ). At least 14 days should elapse between the discontinuation of an MAO inhibitor and the start of a serotonin re-uptake inhibitor or vice-versa, with the exception of fluoxetine. Allow at least five weeks between discontinuation of fluoxetine and initiation of Phenelzine Sulfate Tablets and at least 14 days between discontinuation of Phenelzine Sulfate Tablets and initiation of fluoxetine, or other serotoninergic agents. Before initiating Phenelzine Sulfate Tablets after using other serotoninergic agents, a sufficient amount of time must be allowed for clearance of the serotoninergic agent and its active metabolites. The combination of MAO inhibitors and tryptophan has been reported to cause behavioral and neurologic syndromes including disorientation, confusion, amnesia, delirium, agitation, hypomanic signs, ataxia, myoclonus, hyperreflexia, shivering, ocular oscillations, and Babinski signs. The concurrent administration of an MAO inhibitor and bupropion hydrochloride (Wellbutrin®) is contraindicated. At least 14 days should elapse between discontinuation of an MAO inhibitor and initiation of treatment with bupropion hydrochloride. Patients taking Phenelzine Sulfate Tablets 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 Sulfate Tablets and spinal anesthesia should be kept in mind. Phenelzine Sulfate Tablets should be discontinued at least 10 days prior to elective surgery. MAO inhibitors, including Phenelzine Sulfate Tablets, are contraindicated in patients receiving guanethidine.

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