Alpha-blockers (prazosin, doxazosin, terazosin and phenoxybenzamine) should be used as first-line agents in suspected pheochromocytoma. Alpha-methyldopa or clonidine may also be used Treatment of benign pheochromocytoma should be surgical resection. The following issues should be considered:
○ until surgery is performed, the use of beta-blockers should be avoided, unless arrhythmias are present and adequate alpha blockade has been achieved; ○ surgical resection should be carefully planned in advance with involvement of a team of surgical, medical, intensivist and anesthesia consultants who have experience in the management of patients with pheochromocytoma; ○ laparoscopic surgery should be considered before open surgery for resection of pheochromocytoma except for very large tumours; ○ administration for 10 to 14 days of phenoxybenzamine (10 mg to 20 mg two to three times daily), prazosin (1 mg to 3 mg two to three times daily), terazosin (2 mg to 10 mg two times daily) or doxazosin (2 mg to 4 mg two to three times daily) is indicated for patients with severe paroxysmal or sustained hypertension; ○ the tyrosine hydroxylase inhibitor metyrosine (0.25 g to 1 g four times daily) should also be considered; ○ immediately before surgery, administration of intravenous fluids should be considered to ensure adequate volume expansion to avoid shock after tumour removal; ○ for hypertensive crises before/during surgery, phentolamine hydrochloride should be readily available and, if necessary, administered intravenously; and ○ intravenous propranolol should be used for treatment of arrhythmias
For patients with pheochromocytoma diagnosed during early pregnancy, if a decision is made to terminate the pregnancy, this should be performed under alpha and beta blockade (as above), followed immediately by tumour resection. In late pregnancy, alpha and beta blockade, followed by elective caesarean section and immediate tumour resection are recommended For patients with inoperable or metastatic malignant pheochromocytoma, blood pressure control and adrenergic symptoms may be controlled with alpha-adrenergic blockade (phenoxybenzamine, prazosin, doxazosin, terazosin) plus beta blockade and/or tyrosine hydroxylase inhibition with metyrosine. A combination of cyclophosphamide, vincristine and dacarbazine may be used for chemotherapy for metastatic pheochromocytoma. Treatment with high-dose iodine-131 metaiodobenzylguanidine induces only a moderate response, but may help control blood pressure |
