... is to readminister the drug which has been dis-continued. Increased adrenergic activity also occurs as a result of increasedrelease of catecholamines. Examples of this include pheochromocytoma ... theuse of sympathomimetic drugs such as amphetamines, phencyclidine, orcocaine. The drug of choice in these conditions is a direct-acting alpha-blocker,such as phentolamine. Administration of beta-blockers ... severely symptomatic.Symptoms may include palpitations, chest pain, dyspnea, dizziness, or fatigue.Physical examination findings include an irregularly irregular pulse, varyingintensity of the first...