Adult: Initially, 30 mg daily in single or divided doses, until improvement occurs. Increase if necessary after 4 wk up to 60 mg daily for 4-6 wk. Once response is obtained, may gradually reduce to maintenance of 10-20 mg daily, and up to 40 mg daily may be needed in some cases. Elderly: 5-10 mg daily.
Renal Impairment
Severe: Contraindicated.
Hepatic Impairment
Contraindicated.
Contraindications
Cerebrovascular disorders, severe CV disease, actual or suspected phaeochromocytoma. Hepatic and severe renal impairment. Concomitant admin w/ other MAOIs, SSRIs or TCAs, indirectly-acting sympathomimetic agents, dopamine or levodopa, other CNS depressants, stimulants, local anaesth, ganglion-blocking agents and other hypotensives, diuretics, vasopressors, anticholinergic drugs and hypoglycaemic agents, pethidine.
Special Precautions
Patient w/ CV disease, DM or blood dyscrasias. Avoid abrupt withdrawal. Mild to moderate renal impairment. Elderly and debilitated patients. Pregnancy and lactation.
Adverse Reactions
Orthostatic hypotension, associated in some patients w/ disturbances in cardiac rhythm, peripheral oedema, complaints of dizziness, dry mouth, nausea and vomiting, constipation, blurred vision, insomnia, drowsiness, weakness and fatigue. Infrequent reports of mild headaches, sweating, paraesthesia, peripheral neuritis, hyperreflexia, agitation, overactivity, muscle tremor, confusion and other behavioural changes, difficulty in micturition, impairment of erection and ejaculation, skin rashes, increased appetite, wt gain. Rarely, blood dyscrasias (e.g. purpura, granulocytopenia).
This drug may cause drowsiness, if affected, do not drive or operate machinery. Eat only fresh food and avoid food that is suspected of being stale or 'going off'. Avoid alcoholic drinks or de-alcoholised (low alcohol) drinks.
Monitoring Parameters
Perform regular monitoring of liver function during therapy. Monitor BP, heart rate, mood, suicidal ideation (esp at the beginning of therapy or when doses are adjusted).
Overdosage
Symptoms: Dizziness, ataxia, irritability, hypotension or HTN, tachycardia, pyrexia, psychotic manifestations, convulsions, resp depression and coma. Management: Perform gastric lavage soon after ingestion and carry out intensive supportive therapy. May treat severe hypotension w/ plasma expanders. Hypertensive crises may be treated by pentolinium or phentolamine, severe shock w/ hydrocortisone. May use diazepam to control convulsions or severe excitement.
Drug Interactions
Potentially Fatal: May cause serotonin syndrome w/ other MAOIs, SSRIs or most TCAs (e.g. clomipramine, desipramine, imipramine, butriptyline, bortriptyline). May potentiate actions of indirectly-acting sympathomimetic agents (e.g. amfetamines, metaraminol, fenfluramine or similar anorectic agents, ephedrine or phenylpropanolamine), dopamine or levodopa, other CNS depressants (esp barbiturates and phenothiazines), stimulants, local anaesth, ganglion-blocking agents and other hypotensives, diuretics, vasopressors, anticholinergic drugs and hypoglycaemic agents. May cause serious, potentially fatal reactions when given w/ pethidine.
Food Interaction
Avoid food or beverage w/ high tyramine content (e.g. mature cheese, hydrolysed yeast or meat extracts, alcoholic beverages, non-alcoholic beers, lagers, wines, and other food which are not fresh and are fermented, pickled, 'hung', 'matured' or otherwise subject to protein degradation before consumption); broad bean pods, banana skins, as these may cause sudden and severe high BP (hypertensive crisis or serotonin syndrome).
Action
Description: Isocarboxazid, a hydrazine derivative, is an irreversible inhibitor of both monoamine oxidase types A and B. It increases endogenous concentrations of epinephrine, norepinephrine, dopamine, and serotonin through inhibition of the enzyme, monoamine oxidase, responsible for the breakdown of these neurotransmitters. Pharmacokinetics: Absorption: Readily absorbed from the GI tract. Time to peak plasma concentration: 3-5 hr. Metabolism: Undergoes hepatic metabolism. Excretion: Via urine mainly as metabolites.
Chemical Structure
Isocarboxazid Source: National Center for Biotechnology Information. PubChem Database. Isocarboxazid, CID=3759, https://pubchem.ncbi.nlm.nih.gov/compound/Isocarboxazid (accessed on Jan. 21, 2020)