Furazolidone Sympathomimetics

Clinically important, potentially hazardous interactions with albuterol, alpha-blockers, amitriptyline, amoxapine, atenolol, beta-blockers, carteolol, chlorpromazine, clomipramine, cocaine, desipramine, doxepin, ephedra, ergotamine, furazolidone, halothane, imipramine, insulin detemir, MAO inhibitors, metoprolol, nadolol, nortriptyline, oxprenolol, penbutolol, phenelzine, phenoxybenzamine, phenylephrine, pindolol, prazosin, propranolol, protriptyline, sympathomimetics, terbutaline, thioridazine, timolol, tranylcypromine, tricyclic antidepressants, trimipramine, vasopressors... 

After 5 to 10 days of use furazolidone has MAO-inhibitory activity about equivalent to that of the non-selective MAOIs. The concurrent use of furazolidone with indirectly-acting sympathomimetic amines (amfetamines, phenylpropanolamine, ephedrine, etc.) or with tyramine-rich foods and drinks may be expected to result in a potentially serious rise in blood pressure. However, direct evidence of accidental adverse reactions of this kind does not seem to have been reported. The pressor effects of noradrenaline (norepinephrine) are unchanged by furazolidone. 

The MAO-inhibitory activity of furazolidone is not immediate and may in fact be due to a metabolite of furazolidone. It develops gradually so that after 5 to 10 days of use, indirectly-acting sympathomimetics will interact with furazolidone in the same way as they do in the presence of other... 

The answer is 3 [IIC Tible 15-1]. The halocarbon compounds (e.g., chloroform, halothane, freon) and the fumes from overheated synthetic fluorine-containing resin-coated (Teflon) cookware are indirectly car-diotoxic because they sensitize the heart to sympathomimetic amines such as epinephrine. Following exposure to these substances, even the release of endogenous epinephrine associated with stress can pose a hazard. Yew plants contain a cardioactive alkaloid that inhibits depolarization and produces bradycardia and diastolic heart block. Furazolidone interferes with intermediary metabolism, resulting in a lack of energy arid a dilated, weak heart "round heart." Digitalis aflecTs potassium content in the cell. Monensin is an ionophore that alters the sodium-to-calcium ratio arid leads Id cardiac necrosis. 

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