Clonidine Suppression Test Revisited

Abstract

Background: The diagnosis of pheochromocytoma may be difficult because the clinical picture is variable. Objective: The purpose of this paper is to report our experience and to review the published data on the diagnostic significance and risks of the clonidine suppression test in the diagnosis of pheochromocytoma. Patients and Methods: 114 patients were evaluated for pheochromocytoma using the clonidine suppression test. Results: The diagnosis was established in four patients. Overall accuracy of the test in our own series was 98% when the normal response to clonidine was defined as total plasma catecholamines of less than 500 ng/L, or less than 70% of the baseline value. No serious complication was noted. Conclusion: Our data and the published series demonstrate that the clonidine suppression test is accurate and safe in patients with suspected pheochromocytoma.