Tranylcypromine Adrenaline

Acute treatment with nonselective MAO inhibitors (iproniazid, tranylcypromine, phenelzine), as a consequence of inhibiting both forms of the enzyme, increase, brain levels of all monoamines (phenylethylamine, tryptamine, methylhistamine aminergic neurotransmitters (dopamine, noradr enaline, adrenaline and serotonin). By contrast MAO-A inhibitors (clorgyline) increase serotonin and noradrenaline, while MAO-B inhibitors (selegiline, rasagiline) increase brain levels... 

Considerable interest has recently been aroused by reports that patients treated with monoamine oxidtise inhibitors may suffer severe hypertensive attacks after taking certain foods, notably cheese - , beans and extracts of yeast . Some of these attacks have proved fatal. The hypertensive crises arise as a result of pressor substances in the offending foods (such as tyramine in cheese) which are absorbed unchanged into the blood stream when intestinal and liver monoamine oxidase is inhibited . Some of the inhibitors (tranylcypromine is an example) also have sympathomimetic actions which will contribute to the hypertensive effect. The administration of sympathomimetic substances—such as adrenaline in a local anaesthetic—to patients treated with monoamine oxidase inhibitor also creates a dangerous situation. The possibility of hypertensive crises clearly constitutes a serious hazard of therapy with these enzyme inhibitors. In many instances their limited effectiveness would not justify the exposure of patients to these hazards. 

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