Once phaeochromocytoma is diagnosed, preoperatively following is given

Once a phaeochromocytoma has been diagnosed, an a- adrenoreceptor blocker (phenoxybenzamine) is used to block the effects of catecholamine excess and its consequences during surgery. A dose of 20 mg of phenoxybenzamine initially should be increased daily by 10 mg until a daily dose of 100-160 mg is achieved and the patient repos symptomatic postural hypotension. Additional b-blockade is required if tachycardia or arrhythmias develop; this should not be introduced until the patient is a-blocked. The infusion of large volumes of fluid or administration of noradrenaline can be necessary to correct postoperative hypotension in the presence of unopposed a-blockade.Ref: Bailey and Love 27e pg: 846