Editorimu Modification of Insulin and Sulfonylurea Hypoglycemia by M0n0am1ne-0x1dase Inhibitor Drugs

The moncamine-oxidase inhibitors (MAOI's) were introduced into therapeutics in 1957 and despite numerous toxic effects are in widespread use today.* The bulk of these drugs are employed by psychiatrists for the hospital and office treatment of depression. However, they also find a use in cardiology in the management of angina pectoris and hypertension. All the MAOI's possess in common the ability of inhibiting amine-oxidase in vivo. Amine-oxidase has the important function of degrading various biologically occurring monoamines, such as 5-hydroxytryptamine, tryptamine, tyramine, and to a lesser extent the catecholamines, dopamine, adrenalin and noradrenalin. The MAOI's in clinical use have an irreversible action on amine-oxidase which persists for days, or even weeks until the enzyme is resynthesized. The effects of small daily doses of MAOI's are therefore cumulative. (MAOI's are fairly quickly eliminated from the tissues within two to four days.) Monoamine-oxidase inhibitors may potentiate or change the actions of several drugs, or enhance the pharmacological properties of amines or amine precursors such as tyramine or L-dopa, which occur naturally in certain foodstuffs, e.g., cheese, broad beans, chicken livers, marmite, etc. In some cases the underlying mechanisms have been elucidated experimentally and those situations in which potentiation may occur can now be reasonably predicted. This relates particularly to acute hypertensive crises which have been seen to follow com-