THE EFFECTS OF VERAPAMIL AND DILTIAZEM PRETREATMENT ON POTASSIUM RELEASE IN DOGS AFTER THE ADMINISTRATION OF SUCCINYLCHOLINE

Verapamil exacerbates the increase in serum potassium after a large-do se potassium infusion or after the TV administration of succinylcholin e. We conducted a study in 12 canines conditioned fur 30 days acting a s their own controls. The canines had chronic tracheotomies and caroti d loops performed 2 wk before the experiment. Control canines were giv en 1 mg/kg succinylcholine at Time 0. Blood samples were analyzed for potassium at 0, 1, 3, 5, 10, 15, 30, and 60 min. One week later, the d ogs received 0.15 mg/kg of either verapamil or diltiazem, followed by a 5.6-mu g.kg(-1).min(-1) 10-min infusion of the same drug. The animal s were then even a bolus dose of succinylcholine 1 mg/kg, and the bloo d potassium was analyzed as before. There was no significant differenc e in the potassium concentration before the succinylcholine injection (Time 0) between the study groups. The canines pretreated with verapam il had a significantly greater increase (24% +/- 8%) in potassium conc entration than the control canines (14% +/- 6%) 15 min after succinylc holine administration. There was no difference between the potassium c oncentrations of the diltiazem-pretreated canines and the control grou p at any time point. Therefore, diltiazem pretreatment does not signif icantly influence potassium regulation after a succinylcholine injecti on, whereas verapamil pretreatment has measurable hyperkalemic effects . Implications: Succinylcholine is a drug that causes blood potassium to increase. Potassium influences heart rhythm. Verapamil and diltiaze m are drugs used for angina heart pain. We used dogs to determine the effect of verapamil or diltiazem on the blood's potassium after an inj ection of succinylcholine and found that verapamil had the greatest ef fect.