In the previous three sessions you have learnt about inhalation anesthetics, intravenous anesthetics and the muscle relaxants for initiation as well as maintenance of anesthesia. Anesthetic agents may coadminster with some drugs which had been taken preoperatively for the management of chronic medical problems such as cardiovascular problem, renal problem and others or used in life saving procedure intraoperatively. Anesthetic drugs have great interaction with various drugs. Inorder to manage patients with coexisting disease who has been taken other drugs and to effectively utilize the benefits of these drugs intraoperatively when indicated the learner should have to understand the pharmacologic principles and how to use it. This session will equip the learner with knowledge, skill and attitude to use adrenergic agonist/antagonist, calcium channel blocker, digitalis and diuretics with the anesthetic agents in a minimized risk.