Antidepressant agents sympathomimetic amines

MAOIs have the most serious pharmacodynamic interactions of any antidepressant class. As discussed earlier, they can cause a hypertensive crisis and the serotonin syndrome. They potentiate the hypertensive effects of most sympathomimetic amines, as well as tyramine, which is the reason for the avoidance of over-the-counter preparations containing such agents, in addition to the tyramine-free diet ( 508, 509). The serotonin syndrome occurs most often when MAOIs are used in combination with SSRIs and venlafaxine but it can also occur when MAOIs are used with tryptophan, 5-hydroxytryptophan, and some narcotic analgesics. In addition, MAOIs can also significantly potentiate the sedative and respiratory depressant effects of narcotic analgesics. 

Tricyclic antidepressants potentiate the pressor effects of directly acting sympathomimetic amines, such as adrenaline (epinephrine) or noradrenaline (norepinephrine), to cause hypertension. Small amounts of these, such as may be present in local anaesthetic solutions, can be dangerous. Tricyclic antidepressants will inhibit the antihypertensive effects of the older anti hypertensive drugs, such as adrenergic neurone-blocking agents, e.g. guanethidine, a-methyl-DOPA, and clonidine. 

Potent Antidepressant Agents. Aralkylhydrazines. In the search for sympathomimetic agents with a greater intensity and duration of action, Biel and coworkers (19, 22) investigated a large number of phenylalkylhydrazines which were patterned structurally after the sympathomimetic amines. In essence, the hydrazine moiety either replaced an amino radical or served to produce a nitrogen isostere of a sympathomimetic amine ... 

The most signifioant interaotions of organic nitrates are with those agents that cause hypotension, suoh as other vasodilators, alcohol, and tricyclic antidepressants, in which the potential for orthostatio hypotension may arise. On the other hand, concurrent administration with sympathomimetic amines, such as ephedrine and norepinephrine, may lead to a decrease in the antianginal efficacy of the organic nitrates. 

Boakes AJ, Laurence DI Teoh PC, Barar FSK, Benedikter LT, Prichard BNC. Interactions between sympathomimetic amines and antidepressant agents in man. BMJ 913) 1, 311-15. 

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