Additive effect on the sinus & AV nodes w/ Ca-antagonists of the verapamil or diltiazem type. Exaggerated BP increases w/ norepinephrine or MAOIs; abrupt w/drawal of concomitant clonidine. Exaggerated BP reductions w/ diuretics, phenothiazines, narcotics, or other antihypertensives, hypotensive agents. Additive cardiodepressant effects w/ narcotics or anti-arrhythmic drugs. Enhanced negative chronotropic & negative dromotropic effects w/ reserpine, clonidine, α-methyldopa, guanfacine, &/or cardiac glycosides. Enhanced neuromuscular blockade of tubocurarine. Induced hypoglycemia & masked symptoms w/ insulin or oral antidiabetics.