Overview
DESCRIPTION Marplan (isocarboxazid), a monoamine oxidase inhibitor, is available for oral administration in 10-mg tablets. Each tablet also contains lactose, corn starch, povidone, D&C Red No. 27, FD&C Yellow No. 6, and magnesium stearate. Chemically, isocarboxazid is 5-methyl-3-isoxazolecarboxylic acid 2-benzylhydrazide.
Mechanism of Action
CLINICAL PHARMACOLOGY Pharmacodynamics Isocarboxazid is a non-selective hydrazine monoamine oxidase (MAO) inhibitor. In vivo and in vitro studies demonstrated inhibition of MAO in the brain, heart, and liver. The mechanism by which MAO inhibitors act as antidepressants is not fully understood, but it is thought to involve the elevation of brain levels of biogenic amines. However, MAO is a complex enzyme system, widely distributed throughout the body, and drugs that inhibit MAO in the laboratory are associated with a number of clinical effects. Thus, it is unknown whether MAO inhibition per se, other pharmacologic actions, or an interaction of both is responsible for the antidepressant effects observed. Pharmacokinetics Marplan pharmacokinetic information is not available.
Indications
- INDICATIONS AND USAGE Marplan is indicated for the treatment of depression. Because of its potentially serious side effects, Marplan is not an antidepressant of first choice in the treatment of newly diagnosed depressed patients. The efficacy of Marplan in the treatment of depression was established in 6-week controlled trials of depressed outpatients. These patients had symptoms that corresponded to the DSM-IV category of major depressive disorder; however, they often also had signs and symptoms of anxiety (anxious mood, panic, and/or phobic symptoms) ( see CLINICAL PHARMACOLOGY ).
Common Doses
- 10 mg
- 40 mg
- 20 mg
- 60 mg
Dosage
DOSAGE AND ADMINISTRATION For maximum therapeutic effect, the dosage of Marplan must be individually adjusted on the basis of careful observation of the patient. Dosage should be started with one tablet (10 mg) of Marplan twice daily. If tolerated, dosage may be increased by increments of one tablet (10 mg) every 2 to 4 days to achieve a dosage of four tablets daily (40 mg) by the end of the first week of treatment. Dosage can then be increased by increments of up to 20 mg/week, if needed and tolerated, to a maximum recommended dosage of 60 mg/day.
Black Box Warning
Suicidality and Antidepressant Drugs Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies with Major Depressive Disorder (MDD) and other psychiatric disorders. Anyone considering the use of Marplan or any other antidepressant in a child, adolescent or young adult must balance this risk with the clinical need.
Contraindications
- CONTRAINDICATIONS Marplan (isocarboxazid) should not be administered in combination with any of the following: MAO inhibitors or dibenzazepine derivatives; sympathomimetics (including amphetamines); some central nervous system depressants (including narcotics and alcohol); antihypertensive, diuretic, antihistaminic, sedative or anesthetic drugs, buproprion HCL, buspirone HCL, dextromethorphan, cheese or other foods with a high tyramine content; or excessive quantities of caffeine.
Side Effects
- ADVERSE REACTIONS Adverse Findings Observed in Short-Term, Placebo-Controlled Trials Systematically collected data are available from only 86 patients exposed to Marplan, of whom only 52 received doses of ≥50 mg/day, including only 11 who were dosed at ≥60 mg/day. Because of the limited experience with systematically monitored patients receiving Marplan at the higher end of the currently recommended dose range of up to 60 mg/day, caution is indicated in patients for whom a dose of 40 mg/day is exceeded ( see WARNINGS ).
Interactions
- Drug Interactions See CONTRAINDICATIONS , WARNINGS , and PRECAUTIONS sections for information on drug interactions. Marplan should be administered with caution to patients receiving Antabuse ® (disulfiram, Wyeth-Ayerst Laboratories). In a single study, rats given high intraperitoneal doses of an MAO inhibitor plus disulfiram experienced severe toxicity, including convulsions and death. Concomitant use of Marplan and other psychotropic agents is generally not recommended because of possible potentiating effects.