Terazosin as First Line Preoperative Blockade in Filipino Patients Diagnosed with Pheochromocytoma

Abstract

Pheochromocytoma, a rare cause of hypertension, is potentially fatal if left untreated. Definitive treatment is resection of the mass. Preoperative blockade is important to improve intraoperative hemodynamic stability and reduce morbidity during resection. Phenoxybenzamine, a non-selective alpha adrenergic blocker, has been widely used as preoperative blockade, but is unavailable in the Philippines. Terazosin, a selective alpha 1 antagonist and is widely available as treatment for benign prostatic hypertrophy, has been documented in reports as a suitable preoperative drug in reducing blood pressure in pheochromocytoma patients. The objective is to present four cases of Filipino pheochromocytoma patients who were treated with terazosin as first line preoperative blockade. Four Filipino patients from the Philippine General Hospital were diagnosed with pheochromocytoma based on biochemical and imaging studies. They were started on different doses of terazosin, the maximum dose as high as 4 mg per day. One patient experienced orthostatic hypotension at this dose, but was resolved after reducing the dose to 3 mg per day. A beta blocker (metoprolol on 3 cases, carvedilol) was added for reduction of the symptoms. One patient was also diagnosed with diabetic ketoacidosis, and was treated as such. Two patients experienced labile changes with blood pressure during resection but were resolved with the use of intravenous nicardipine for elevated blood pressure, and crystalloids during bouts of hypotension. All of the patients' blood pressure returned to normal after resection of the mass.
Terazosin, a selective alpha 1 antagonist, at a maximum dose of 4 mg per day, may be safely given to Filipino patients diagnosed with pheochromocytoma as first line preoperative blockade.