Dosing and uses of Marplan (isocarboxazid)
Adult dosage forms and strengths
tablet
- 10 mg
Depression
10 mg PO q6-12hr, increase by 10 mg/day q2-4d to 40 mg/day PO divided q6-12hr by end of first week
After first week, may increase by up to 20 mg/week to maximum 60 mg/day; decrease dose to maintenance dose once maximum effect achieved
Pediatric dosage forms and strengths
Safety and efficacy not established
Geriatric dosage forms and strengths
Depression
10 mg PO q6-12hr, increase by 10 mg/day q2-4d to 40 mg/day PO divided q6-12hr by end of first week
After first week, may increase by up to 20 mg/week to maximum 60 mg/day; decrease dose to maintenance dose once maximum effect achieved
Marplan (isocarboxazid) adverse (side) effects
Frequency not defined
Common
- Orthostatic hypotension
- Dizziness
- Crowsiness
- Fatigue
- Headache
- Hyperreflexia
- Sleep disturbance
- Weakness
- Tremor
- Constipation
- Dry mouth
Less Common
- Confusion
- Decreased memory
- Paresthesia
- Anorexia
- Nausea
- Vomiting
- Impotence
- Urinary frequency or retention
- Nystagmus
Uncommon
- Edema
- Anxiety
- Hypomania
- Irritation
- Hypermetabolic syndrome (hyperpyrexia, tachycardia, tachypnea, incr CPK, acidosis)
- SIADH
- Arthralgia
Rare
- Risk of hypertensive crisis (usually due to drug interaction)
- Ataxia
- Seizure
- Jaundice
- Visual disturbance
Warnings
Black box warnings
In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (<24 yr of age) taking antidepressants for major depressive disorders and other psychiatric illnesses
This increase was not seen in patients aged >24 years; a slight decrease in suicidal thinking was seen in adults >65 years
In children and young adults, risks must be weighed against the benefits of taking antidepressants
Patients should be monitored closely for changes in behavior, clinical worsening, and suicidal tendencies; this should be done during initial 1-2 months of therapy and dosage adjustments
The patient’s family should communicate any abrupt changes in behavior to the healthcare provider
Worsening behavior and suicidal tendencies that are not part of the presenting symptoms may require discontinuation of therapy
This drug is not approved for use in pediatric patients
Contraindications
Hypersensitivity
Pheochromocytoma, CHF, cerebrovascular defect, CVD, HTn
Schizophrenia
History of severe or frequent headaches, liver disease
Use with SSRIs or TCAs (eg., wait 5 weeks between discontinuation of fluoxetine and initiation of isocarboxazid)
Use with MAO inhibitors (wait 1 week between discontinuation of MAO inhibitor and initiation of isocarboxazid)
Concurrent use with CNS depressants may result in delirium, hyperpyrexia, seizures, coma, excitation, and hyper/hypotension
Hypertensive reactions may occur from consumption of foods high in tyramine or supplements containing caffeine, tyrosine, tryptophan, phenylalanine, or phenylalanine
Discontinue 10 days before surgery
Concurrent use of sympathomimetics
Cautions
Doses >40 mg/day
Clinical worsening & suicide ideation may occur despite medication in adolescents & young adults (18-24 years)
Caution in patients with diabetes mellitus (monitor glucose closely), glaucoma, hepatic/renal impairment, history of seizures, thyroid dysfunction
Drug may worsen psychosis in patients with bipolar disorder
Pregnancy and lactation
Pregnancy category: C
Lactation: unknown; use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Marplan (isocarboxazid)
Mechanism of action
Nonselective monoamine oxidase inhibitor; may inhibit the enzyme monoamine oxidase, which is responsible for the breakdown of dopamine, serotonin, epinephrine, and norepinephrine, in turn causing an increase in endogenous concentrations of these neurotransmitters.
Pharmacokinetics
Effects may continue up to 2 wk after discontinuation
