Anti-hypertensive treatment in pheochromocytoma and paraganglioma: current management and therapeutic features.

Pheochromocytoma (PH) and paraganglioma (PG) are neuroendocrine neoplasms arising from chromaffin cells of the adrenal medulla and the sympathetic ganglia, respectively. Although are unusual cause of hypertension (HT) accounting for at most 0.1-0.2 % of cases, they may lead to severe and potentially lethal hypertensive crisis due to the effects of the released catecholamines. However, both PH and PG may be asymptomatic as similar to 30 % of subjects are normotensive or have orthostatic hypotension and in these cases the 24 h ambulatory blood pressure (BP) monitoring is an important toll to diagnose and treat HT. HT treatment may be difficult when PH or PG occurs in pregnancy or in the elderly subjects and in these cases a multidisciplinary team is required. When surgical excision is mandatory the perioperative management requires the administration of selective alpha 1-adrenergic blocking agents (i.e., doxazosin, prazosin or terazosin) followed by a beta-adrenergic blockade (i.e., propranolol, atenolol). This latter should never be started first because blockade of vasodilatory peripheral beta-adrenergic receptors with unopposed alpha-adrenergic receptor stimulation can lead to a further elevation of BP. Although labetalol is traditionally considered the ideal agent due to its alpha- and beta-adrenergic antagonism, experimental studies do not support its use in this clinical setting. As second regimen, the administration of vasodilators as calcium channel blockers (i.e., nicardipine, nifedipine) may be required to control BP. Oral and sublingual short-acting nifedipine are potentially dangerous in patients with hypertensive emergencies and are not recommend. The latest evidences into the diagnosis and treatment of hypertensive crisis due to PH and PG are reviewed here.