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Adrenal Gland

Captopril suppression test


Author: Renu Virk, M.D. (see Authors page)

Revised: 21 September 2012, last major update - February 2010

Copyright: (c) 2002-2010, PathologyOutlines.com, Inc.




● Confirms the diagnosis of primary (hyper) aldosteronism

● One of four tests recommended for screening or confirmation: also oral sodium loading, saline infusion and fludrocortisone suppression (Horm Metab Res 2010 Jan 29 [Epub ahead of print])

● As effective as sodium loading in confirming the diagnosis of primary aldosteronism (Hypertension 2001; 37:1440, Curr Hypertens Rep 2002;4:245)

● Note: Captopril challenge test is used to diagnose renal artery stenosis, differs in that plasma renin (not aldosterone) is measured (Wikipedia)




● Captopril inhibits conversion of angiotensin I to angiotensin II, thereby decreasing aldosterone production in normal individuals; in patients with primary hyperaldosteronism, the plasma aldosterone levels are NOT suppressed by captopril




Measure plasma aldosterone levels at baseline and 2 hours after patient takes 25mg of captopril orally


Normal range


● Plasma aldosterone concentration (PAC) <15 ng/dl (416pmol.L) and PAC to plasma renin activity (PRA) ratio less than 50


Adverse effects


● Marked hypotension may occur due to captopril intake

● Blood pressure should be monitored regularly


Additional references


eMedicine (primary hyperaldosteronism)


End of Adrenal Gland > Captopril suppression test



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