Caution should be exercised when giving tranylcypromine with the following: guanethidine, as its action may be antagonised; reserpine, as hyperactivity may occur; methyldopa, as central excitation may result; other hypotensive agents because of possible additive effects; oral hypoglycaemic agents or insulin, as their action may be potentiated; anticholinergic antiparkinsonism drugs, as potentiation has been reported, narcotic analgesics, except pethidine which is contra-indicated (see above), because of possible potentiation; and carbamazepine, which has similarities with tricyclic antidepressants.
Metrizamide should be avoided in patients on MAO Inhibitors since they may lower the seizure threshold.
Although MAO Inhibitors have been used therapeutically with L-tryptophan. A neuromotor syndrome has been reported with this combination.
Patients should be specifically asked if they are taking any other medication because of the possibility of drug interactions.
Exercise caution when giving tranylcypromine under following conditions:
• In combination with other monoamine oxidase inhibitors (MAOI). Avoid for at least 2 weeks after stopping previous MAOI (for e.g. furazolidone, isocarboxazid, pargyline HCl and procarbazine HCl) and then start at a reduced dose. Similarly, at least a week should elapse between the discontinuance of tranylcypromine and the administration of another MAOI, or the re-administration of tranylcypromine. Hypertensive crises or severe convulsive seizures may occur in patients receiving such combinations.
• In combination with selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine, sertraline since CNS effects of SSRI may be potentiated. Serious and even fatal reactions (including hyperthermia, rigidity, myoclonus, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation leading to delirium and coma) in patients receiving Fluoxetine in combination with a MAOI, and in patients who have recently discontinued Fluoxetine and are then started on a MAOI. There also have been cases presented with features resembling neuroleptic malignant syndrome. These drugs should not be given together or within 2 weeks of treatment with either drug. MAOIs should not be started until at least 5 weeks after starting Fluoxetine, since Fluoxetine and its major metabolite have very long elimination half-lives.
• In combination with tricyclic antidepressants, due to increased risk of hypertension and CNS excitation. After stopping tranylcypromine, do not start tricyclic related antidepressants (including amitriptyline, carbamazepine or trimipramine) for 2 weeks, also MAO inhibitors should not be started until at least 1-2 weeks (3 weeks in case of clomipramine or imipramine) after stopping tricyclic antidepressants.
• In combination with other antidepressants, due to increased risk of hypertension. At least 10 days should elapse between the discontinuation of MAOI and the start of Buspirone HCl.
• In combination with sympathomimetic drugs including amphetamine, ephedrine, phenylpropanolamine and over-the-counter cough & cold, hay fever or weight reducing preparations containing vasoconstrictors, guanethidine, methyldopa, dopamine, levodopa and reserpine due to the risk of hypertensive crisis, headache and related symptoms. MAOIs in combination with tryptophan have been reported to cause behavioural and neurologic syndromes including disorientation, confusion, amnesia, delirium, agitation, hypomanic signs, ataxia, myoclonus, hyperreflexia, shivering, ocular oscillations and Babinski's signs.
• In combination with anticholinergic anti-parkinsonism drugs. Antiparkinsonism drugs should be used with caution in patients receiving MAOIs.
• In combination with bupropion. The concurrent administration of bupropion and a MAOI is contraindicated. At least two weeks should elapse between discontinuation of a MAOI and initiation of treatment with bupropion HCl.
• Avoid concomitant use with opioid analgesics as possible CNS excitation or depression (hypertension or hypotension) may occur. Wait until two weeks after stopping MAOIs before starting treatment with opioid analgesics.
• In combination with antiepileptics, since MAOIs possibly antagonize anticonvulsant effects of antiepileptics (convulsive threshold lowered).
• In combination with antihistamines, since antimuscarinic and sedative effects of antihistamines are increased by MAOIs.
• Use of MAOIs may enhance the effects of barbiturates and possibly other hypnotics, hypoglycaemics, and possibly antimuscarinic agents.
• In surgery. Patients taking MAOIs should not undergo surgery requiring general anaesthesia. Also, they should not be given cocaine or local anaesthesia containing vasoconstrictors. The possible combined hypotensive effects of MAOIs and spinal anaesthesia should be kept in mind. Discontinue MAOI therapy two weeks before surgery because of the possible hazardous interaction with certain anaesthetics.
Dietary Precautions:
High levels of tyramine in certain foods have been the cause of severe hypertensive reactions in patients on MAO inhibitor therapy (See adverse reactions). Accordingly, patients must be warned to avoid the following: Matured cheeses, hydrolysed protein extracts such as Marmite or Bovril, alcoholic drinks, particularly red wines such as chianti, non-alcoholic beer and lager, and protein foods that are not fresh or whose preparation involved hydrolysis, fermentation, pickling or hanging, also broad bean pods which contain levodopa and banana skins.