Potassium supplementation in ritodrine-induced hypokalemia.

Acute hypokalemia occurs during infusion of beta 2 agonists for tocolysis. This study examines the efficacy of supplemental potassium in treating this hypokalemia. Four groups of dogs were anesthetized and given lactated Ringer's solution (group I), potassium chloride (group II), ritodrine hydrochloride (group III), and ritodrine plus potassium (group IV). Arterial blood gases, pH, and serum and urinary electrolytes were measured. Results were analyzed by an analysis of variance. Serum potassium fell in groups I and III, rose in group II, and remained stable in group IV. Urinary potassium levels in groups that received ritodrine (III and IV) were not different from control levels. Potassium given with ritodrine will prevent hypokalemia. However, the risks of hyperkalemia exist if vigorous replacement is undertaken. There were no dysrhythmias and no adverse effects in any of the hypokalemic animals. Therefore, the routine administration of potassium is not advocated even in obstetric patients who undergo general anesthesia.