Hypertensive crisis in prazosin-treated pheochromocytoma.

The selective alpha1-adrenergic antagonist prazosin has recently been recommended for the preoperative management of pheochromocytoma, but we have observed a hypertensive crisis in a patient with such a tumor, despite prazosin therapy. Her blood pressure was easily controlled with small doses of phenoxybenzamine, suggesting that less selective alpha-adrenergic blockade might be advantageous in this situation. The involvement of alpha 2-adrenoreceptors in pressor responses and a lack of evidence for presynaptic alpha 2 control of peripheral sympathetic tone in man suggest that selective alpha 1-blockade is not the optimal treatment of hypertension due to high levels of circulating catecholamines.