TABLE 2.

Effect on antihypertensive drugs on aldosterone, renin, and aldosterone-to-renin ratio.

Drugs	Effect on aldosterone	Effect on renin	Effect on ARR	Interpretation when testing on drug
Beta-blockers	↓	↓↓	↑ (FP)	Increased ARR clinically not important (false-positive) if aldosterone low
Clonidine	↓	↓↓	↑ (FP)	Same as for beta-blockers
Methyldopa	↓	↓↓	↑ (FP)	Same as for beta-blockers
Calcium blockers (DHP)	↔↓	↔↑	↓ (FN)	Considered non-interfering in the 2020 Italian guidelines
Verapamil	↔	↔	↔	Considered non-interfering
ACEI	↓	↑↑	↓ (FN)	High renin does not exclude PA, testing must be repeated off-drug; low renin is strong predictor of PA
ARB	↓	↑↑	↓ (FN)	Same as for ACE inhibitors
Potassium-wasting diuretics	↔↑	↑↑	↓ (FN)	Considered prohibited during testing
MRA	↔/↑	↔/↑↑	↔/↓ (FN)	Previously considered prohibited during testing; based on the recent data may be continued (also during a confirmatory test and AVS), especially in patients with severe hypokalemia and/or poor BP control, and diagnosis of PA can be made in patients on MRA if aldosterone is high and renin low. However, if renin is not suppressed, then MRA should be discontinued for 4–6 weeks before retesting
Alpha-blockers	↔	↔	↔	Considered non-interfering
Moxonidine	↔	↔	↔	Single study in normotensives; considered non-interfering in the 2020 Italian guidelines
Hydralazine	↔	↔	↔	Rarely used nowadays; considered non-interfering

ACEI, angiotensin-converting enzyme inhibitors; ARB, angiotensin receptor blockers; ARR, aldosterone-to-renin ratio; AVS, adrenal venous sampling; BP, blood pressure; DHP, dihydropyridines; FN, false negatives; FP, false positives; MRA, mineralocorticoid receptor antagonist; PA, primary aldosteronism.