Adult: Initially, 30 mg daily as a single dose or in divided doses for 4 weeks. May increase up to 60 mg daily for 4-6 weeks, if needed. Usual maintenance dose: 10-20 mg daily, or up to 40 mg daily. Elderly: Half the normal maintenance dose.
Renal Impairment
Severe: Contraindicated.
Hepatic Impairment
Contraindicated.
Contraindications
Known or suspected cerebrovascular disorders, CV disease, hypertension or history of headache, known or suspected phaeochromocytoma. Hepatic impairment (including history of liver disease or abnormal LFTs) and severe renal impairment. Concomitant use with or within 14 days of stopping SSRIs or other MAOIs; indirectly-acting sympathomimetic agents (e.g. amphetamines, metaraminol, fenfluramine, anorectic agents, ephedrine, phenylpropanolamine, dopamine, levodopa), pethidine, certain CNS depressants (including narcotics), antihypertensives, diuretic, antihistamines, sedatives or anaesthetic drugs, bupropion, buspirone, dextromethorphan, dibenzazepine derivatives, general anaesthesia used during elective surgery.
Special Precautions
Patient with diabetes, blood dyscrasias; at risk for seizure (e.g. history of seizure, head trauma, brain damage), history of suicide-related events, significant degree of suicidal ideation, history of substance abuse disorder, hyperthyroidism, schizophrenia, bipolar disorder, hypovolaemia. Restless or agitated patients; debilitated patients. Avoid abrupt withdrawal. Patients who will undergo surgery; discontinue treatment for at least 2 weeks prior to elective surgery. May mask anginal pain. Mild to moderate renal impairment. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Orthostatic hypotension, hepatic complications, jaundice, suicidal thoughts, self-harm, suicide-related events, increase or decrease in frequency of seizures; excessive excitement (in restless or agitated patients); shift to mania or hypomania (in patients with bipolar disorder). Cardiac disorders: Palpitations. Eye disorders: Blurred vision. Gastrointestinal disorders: Dryness of mouth, nausea, vomiting, constipation. General disorders and administration site conditions: Peripheral oedema, weakness, fatigue. Nervous system disorders: Dizziness, drowsiness, headache, tremor, myoclonic jerks, paraesthesia. Psychiatric disorders: Insomnia. Renal and urinary disorders: Impotence, urinary frequency, urinary hesitancy. Skin and subcutaneous tissue disorders: Diaphoresis. Potentially Fatal: Hypertensive crisis.
This drug may cause drowsiness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor renal function and liver function at baseline and as necessary; blood pressure, heart rate. Assess for changes in mood, signs and symptoms of suicidal ideation (particularly at the start of therapy and when doses are adjusted).
Overdosage
Symptoms: Ataxia, dizziness, irritability. For acute cases, hypotension or hypertension, convulsions, psychotic manifestation, tachycardia, respiratory depression, coma. Management: Supportive treatment. While keeping the airways protected, perform gastric lavage; provide emetics immediately after ingestion. For severe cases of hypotension, give plasma expanders. Administer pentolinium or pentolamine for hypertensive crisis and hydrocortisone for severe shock. Give diazepam to control convulsions or severe excitement. May perform dialysis in severe cases to eliminate the drug.
Drug Interactions
May potentiate the action of indirectly-acting sympathomimetic agents such as amphetamines, metaraminol, fenfluramine, or similar anorectic agents, ephedrine, or phenylpropanolamine, dopamine, levodopa; other CNS depressants (particularly barbiturates, phenothiazines), stimulants, local anaesthetics, ganglion-blocking drugs, other hypotensives (e.g. methyldopa, reserpine), diuretics, vasopressors, anticholinergic drugs, hypoglycaemic drugs. May enhance the side effect of morphine. May increase the hypertensive effect of bupropion and buspirone. Increased risk of brief psychotic episodes or bizarre behaviour with dextromethorphan. Increased risk of orthostatic hypotension with drugs that predispose to hypotension or bradycardia. Potentially Fatal: Increased risk of serotonin syndrome with SSRIs or other MAOIs. Increased risk for central excitation, muscle rigidity, hyperpyrexia, circulatory collapse, respiratory depression and coma with pethidine.
Food Interaction
May cause sudden and severe high blood pressure (e.g. hypertensive crisis or serotonin syndrome) with tyramine-containing foods such as mature cheeses (including processed cheeses), hydrolysed yeast or meat extracts, alcoholic beverages (especially heavy red wines), non-alcoholic beers, lagers, wines and other fermented food, pickles, hung, matured or otherwise subject to protein degradation before consumption; tyrosine, phenylalanine, tryptophan or caffeine-containing foods; avoid concurrent ingestion.
Action
Description: Mechanism of Action: Isocarboxazid is a hydrazine derivative that inhibits the monoamine oxidase enzyme, therefore increasing the endogenous concentrations of epinephrine, norepinephrine, dopamine, and serotonin. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Time to peak plasma concentration: 3-5 hours. Metabolism: Metabolised in the liver. Excretion: Via urine (primarily as metabolites).
N06AF01 - isocarboxazid ; Belongs to the class of non-selective monoamine oxidase inhibitors. Used in the management of depression.
References
Anon. Isocarboxazid. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 08/03/2023.Buckingham R (ed). Isocarboxazid. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 08/03/2023.Joint Formulary Committee. Isocarboxazid. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 08/03/2023.Marplan Tablet (Validus Pharmaceuticals LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/03/2023.