Post-op IA continuous infusion. Monitor CV & resp vital signs, patient's state of consciousness, neurologic impairment. Patient w/ epilepsy, impaired cardiac conduction, bradycardia, severe shock or digitalis intoxication, Stokes-Adam syndrome or Wolff-Parkinson-White syndrome. Central nerve blocks. Preexisting abnormal neurological pathology. Hepatic & renal impairment. Foetal bradycardia/tachycardia. Monitor ECG for patient under antiarrythmic drugs class III. Severe & untreated HTN, arteriosclerotic heart disease, cerebral vascular insufficiency, heart block, advanced diabetes, poorly controlled thyrotoxicosis, ventricular fibrillation, prefibrillatory rhythm, tachycardia, MI, phenothiazine-induced circulatory collapse & prostatic hypertrophy. Porphyric patients. May impair ability to drive or operate machinery.