Drug Class Description

Generic Name

Drug Description

Presentation

Indications

Adult Dosage

Oral administration.

Adults:

One 15mg tablet three times a day. A response is usually seen within the first week. If no response is evident after two weeks, the dosage may be increased to a maximum of one 15mg tablet four times a day. Doses of up to two 15mg tablets three times a day may be used in hospitals. The effectiveness of the drug may not become apparent in less than 4 weeks therapy. After a satisfactory response has been achieved, the dosage may be reduced very gradually to a suitable maintenance level. This may be as low as one 15mg tablet every other day.

Child Dosage

As for adults.

Postural hypotension may be an unwanted effect of MAOIs in the elderly. Elderly patients as a group tend to receive multiple drug therapies and the possibility of increased risk of drug interactions should be borne in mind. Nardil should only be used with great caution in elderly patients.

Despite these problems, MAOIs (including Nardil) have been found to be useful in the treatment of depression in the elderly.

Elderly Dosage

Contra Indications

Nardil should not be used in patients who are hypersensitive to any of the ingredients or with phaeochromocytoma, cerebrovascular disease, congestive heart failure, a history of liver disease or with abnormal liver function tests. Phenelzine sulphate should not be administered at the same time as, or within 14 days of, treatment with other MAOIs, buspirone, or dibenzazepine derivative drugs (including tricyclic antidepressant agents, perphenazine or carbamazepine). In the cases of clomipramine and imipramine, 3 weeks should be left before starting phenelzine therapy. It is recognised that there is some division of consultant opinion with respect to concomitant use of MAOIs and tricyclic antidepressants.

There have been reports of serious reactions (including hyperthermia, rigidity, myoclonic movements and death) when serotonin reuptake inhibitors or serotonin/noradrenaline inhibitors (e.g. venlafaxine) have been combined with MAOIs. Therefore, Nardil should not be used in combination with these drugs and before initiating Nardil, a sufficient amount of time must be allowed for clearance of these drugs and their metabolites. For example, five weeks in the case of fluoxetine and two weeks with paroxetine. Conversely, these drugs should not be started within 14 days of discontinuing phenelzine. Phenelzine should not be used in combination with guanethidine, dextromethorphan, or with CNS depressants such as alcohol and narcotic analgesics. Death has been reported in patients receiving a single dose of pethidine.

Phenelzine is not indicated in the manic phase.

Special Precautions

Nardil should be withdrawn two weeks before elective surgery/dentistry.

Nardil should not be given with cocaine or local anaesthesia containing sympathomimetic vasoconstrictors. The possible combined hypotensive effects of Nardil and spinal anaesthesia should be kept in mind.

Potentially suicidal patients should be carefully observed until control of depression is attained. Nardil should be used only with great caution in agitated patients or those who have cardiovascular disease, epilepsy, blood dyscrasias, porphyria or diabetes; and in patients taking diuretics.

Blood pressure should be observed frequently to detect any pressor response and therapy discontinued if palpitations or frequent headaches occur.

Patients should also be closely followed for symptoms of postural hypotension. Hypotensive side effects have occurred in hypertensive as well as normotensive and hypotensive patients.

Due to the possibility of patients undergoing “Withdrawal Syndrome” abrupt withdrawal of phenelzine should be avoided where possible.

Phenelzine may cause excessive stimulation in schizophrenic patients; in manic-depressive states it may result in a swing from a depressive to a manic phase.

Caution should be exercised if the patient undergoes concurrent electroconvulsive therapy (ECT).

Interactions

Patients should be warned against self medication, particularly cold cures, cough cures, hay fever medications, anti-appetite medicines, weight-reducing preparations and “pep” pills and about potential food interactions.

Patients under treatment with Nardil should avoid high protein food that has undergone breakdown by ageing, fermentation, pickling, smoking or bacterial contamination. Patients should avoid cooked or plain cheese, Oxo, Bovril, Marmite, brewer's yeast, etc. during treatment and up to 14 days after ceasing treatment. Flavoured textured vegetable protein, hung game, pickled herrings, dry sausage (salami, pepperoni etc.), liver, yoghurt, broad bean pods, fermented soya bean extract, and excessive amounts of chocolate may also present a hazard. Patients should not consume alcoholic drink or non-alcoholic beers, lagers and wines and excessive amounts of tea and coffee should be avoided.

Where a reaction between Nardil and certain foodstuffs occurs the intensity of the reaction is usually related to the tyramine content of the food. The reaction is now well recognised and serious hypertensive episodes are extremely rare. Should such a reaction occur, the hypertension should be controlled promptly by slow administration of phentolamine 5mg to 10mg IV repeated if necessary. Care should be taken to administer this drug slowly to avoid an excessive hypotensive effect.

Nardil may also potentiate the effects of alcohol.

Nardil may potentiate the action of pethidine, morphine, adrenaline, amphetamines and other sympathomimetic amines such as fenfluramine, ephedrine, phenylpropanolamine, dopamine and levodopa (see also Contraindications). Nardil may also potentiate the effects of antihypertensives, hypoglycaemic agents, sympathomimetics, anti-Parkinson drugs, antimuscarinics, local anaesthetics and CNS depressants, including barbiturates.

It is suggested that MAOIs are not administered at the same time as, or within 14 days of, treatment with amfebutamone (bupropion) or 5HT₁ agonists.

It is suggested that MAOIs are not administered at the same time as anti-epileptics, altretamine, doxapram, tetrabenazine, oxypertine or clozapine.

The combination of MAOIs and tryptophan has been reported to cause behavioural and neurological symptoms.

Adverse Reactions

Side-effects tend to be mild or moderate in severity, often subsiding as treatment continues, and can be minimised by adjusting dosage; rarely is it necessary to discontinue Nardil.

The most important reaction associated with Nardil is the occurrence of hypertensive crises, which have been associated with intracranial bleeding and have sometimes been fatal.

Common side-effects include: dizziness, drowsiness, weakness and fatigue, oedema, gastro-intestinal disturbances (nausea, vomiting, dryness of the mouth, constipation), insomnia, blurred vision, adverse effects on driving ability, postural hypotension, twitching, myoclonic movements, hyperreflexia, elevated serum transaminases and anorgasmia.

Uncommon side-effects are headache, nervousness, euphoria, paraesthesia, sweating, increased appetite and weight, rash, pruritus, difficulty in micturition, muscle tremor, peripheral neuritis, behavioural changes, arrhythmias, convulsions, impotence and delayed ejaculation, purpura, blood dyscrasias, jitteriness, palilalia, nystagmus, hypernatraemia, glaucoma, lupus-like illness, confusion, hallucinations and elevated liver enzymes.

Other severe side-effects have been reported very rarely, including isolated reports in some cases. These include: ataxia, shock-like coma, toxic delirium, neuroleptic malignant syndrome (occasionally fatal), manic reaction, acute anxiety reaction, precipitation of schizophrenia, transient respiratory and cardiovascular depression following ECT, fatal progressive necrotising hepatocellular damage, reversible jaundice, hypermetabolic syndrome, oedema of the glottis and fever associated with increased muscle tone.

Hyponatraemia (usually in the elderly and possibly due to inappropriate secretion of antidiuretic hormone) has been associated with all types of antidepressants and should be considered in all patients who develop drowsiness, confusion or convulsions while taking an antidepressant.

Withdrawal may be associated with nausea, vomiting and malaise. An uncommon withdrawal syndrome following abrupt withdrawal of Nardil has been infrequently reported. Signs and symptoms of this syndrome generally commence 24 to 72 hours after drug discontinuation and may vary from vivid nightmares and agitation to frank psychosis and convulsions. This syndrome generally responds to reinstitution of low-dose Nardil therapy followed by cautious downward titration and discontinuation.

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