The safe use of Phenelzine Sulfate Tablets 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.
Doses of Phenelzine Sulfate Tablets in pregnant mice well exceeding the maximum recommended human dose have caused a significant decrease in the number of viable offspring per mouse. In addition, the growth of young dogs and rats has been retarded by doses exceeding the maximum human dose.
Prescribers or other health professionals should inform patients, their families, and their caregivers about the benefits and risks associated with treatment with Phenelzine Sulfate Tablets and should counsel them in its appropriate use. A patient Medication Guide about “Antidepressant Medicines, Depression and other Serious Mental Illness, and Suicidal Thoughts or Actions” is available for Phenelzine Sulfate Tablets. The prescriber or health professional should instruct patients, their families, and their caregivers to read the Medication Guide and should assist them in understanding its contents. Patients should be given the opportunity to discuss the contents of the Medication Guide and to obtain answers to any questions they may have. The complete text of the Medication Guide is reprinted at the end of this document.
Patients should be advised of the following issues and asked to alert their prescriber if these occur while taking Phenelzine Sulfate Tablets.
Clinical Worsening and Suicide Risk
Patients, their families, and their caregivers should be encouraged to be alert to the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behavior, worsening of depression, and suicidal ideation, especially early during antidepressant treatment and when the dose is adjusted up or down. Families and caregivers of patients should be advised to look for the emergence of such symptoms on a day-to-day basis, since changes may be abrupt.
Such symptoms should be reported to the patient’s prescriber or health professional, especially if they are severe, abrupt in onset, or were not part of the patient’s presenting symptoms.
Symptoms such as these may be associated with an increased risk for suicidal thinking and behavior and indicate a need for very close monitoring and possibly changes in the medication.
Anyone considering the use of Phenelzine Sulfate Tablets in a child or adolescent must balance the potential risks with the clinical need.
Phenelzine Sulfate Tablets, as with other hydrazine derivatives, has been reported to induce pulmonary and vascular tumors in an uncontrolled lifetime study in mice.
In depressed patients, the possibility of suicide should always be considered and adequate precautions taken. It is recommended that careful observations of patients undergoing Phenelzine Sulfate Tablets treatment be maintained until control of depression is achieved. If necessary, additional measures (ECT, hospitalization, etc) should be instituted.
All patients undergoing treatment with Phenelzine Sulfate Tablets should be closely followed for symptoms of postural hypotension. Hypotensive side effects have occurred in hypertensive as well as normotensive and hypotensive patients. Blood pressure usually returns to pretreatment levels rapidly when the drug is discontinued or the dosage is reduced.
Because the effect of Phenelzine Sulfate Tablets 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 largely limited to patients in whom disorders characterized by hyperkinetic symptoms coexist with, but are obscured by, depressive affect; hypomania usually appeared as depression improved. If agitation is present, it may be increased with Phenelzine Sulfate Tablets. Hypomania and agitation have also been reported at higher than recommended doses or following long-term therapy.
Phenelzine Sulfate Tablets may cause excessive stimulation in schizophrenic patients; in manicdepressive states it may result in a swing from a depressive to a manic phase.
Phenelzine Sulfate Tablets should be used with caution in diabetes mellitus; increased insulin sensitivity may occur. Requirements for insulin or oral hypoglycemics may be decreased.
MAO inhibitors, including Phenelzine Sulfate Tablets, potentiate hexobarbital hypnosis in animals. Therefore, barbiturates should be given at a reduced dose with Phenelzine Sulfate Tablets.
MAO inhibitors inhibit the destruction of serotonin and norepinephrine, which are believed to be released from tissue stores by rauwolfia alkaloids. Accordingly, caution should be exercised when rauwolfia is used concomitantly with an MAO inhibitor, including Phenelzine Sulfate Tablets.
There is conflicting evidence as to whether or not MAO inhibitors affect glucose metabolism or potentiate hypoglycemic agents. This should be kept in mind if Phenelzine Sulfate Tablets is administered to diabetics.
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)
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.
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, 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.
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