Propranolol Does Not Require Discontinuation for Adrenal Function Testing in Primary Adrenal Insufficiency

Medication Interference with Adrenal Testing

Beta‑blockers, including propranolol, are absent from the lists of drugs that interfere with cortisol measurement or adrenal function testing in the International Consensus Guidelines for Primary Adrenal Insufficiency. 1 (Consensus)
CYP3A4‑inducing agents (e.g., anti‑epileptics, rifampin, phenytoin, phenobarbital) increase cortisol clearance and may confound test results. 1 (Consensus)
CYP3A4‑inhibiting agents (e.g., certain antifungals and antiretrovirals) decrease cortisol clearance and may confound test results. 1 (Consensus)
Etomidate directly suppresses adrenal steroidogenesis and should be avoided before adrenal function testing. 1 (Consensus)

The recommended diagnostic pathway for suspected primary adrenal insufficiency does not require stopping beta‑blockers before testing. 3 (Guideline recommendation)
A morning serum cortisol < 250 nmol/L together with an elevated ACTH level is diagnostic of adrenal insufficiency in the setting of acute illness. 4 (Guideline recommendation)
The standard 250 µg cosyntropin (corticotropin) stimulation test is considered positive when the peak cortisol response is < 500 nmol/L, confirming the diagnosis. 4 (Guideline recommendation)
When adrenal crisis is clinically suspected, testing should be performed immediately and glucocorticoid therapy initiated before results are available. 3 (Guideline recommendation)

Propranolol’s beta‑adrenergic blockade does not directly affect cortisol synthesis or metabolism. 1 (Pharmacologic evidence)
Propranolol does not interfere with ACTH secretion or its action on the adrenal cortex. 5 (Pharmacologic evidence)
Propranolol does not alter aldosterone production pathways. 5 (Pharmacologic evidence)

Propranolol can mask typical hypoglycemia warning signs (tachycardia, tremor) in patients with adrenal insufficiency, requiring clinicians to monitor glucose closely. 2 (Clinical observation)

If hypertension emerges during fludrocortisone replacement, the first step is to reduce the fludrocortisone dose. 4 (Therapeutic guidance)
If blood pressure remains elevated after adjusting mineralocorticoid therapy, addition of vasodilators is recommended while continuing appropriate mineralocorticoid replacement. 3 (Therapeutic guidance)
Beta‑blockers may be employed safely for essential hypertension in patients with primary adrenal insufficiency, as they do not interfere with diagnostic testing. 6 (Therapeutic guidance)

Proceed directly with adrenal function testing (morning cortisol and ACTH) without stopping propranolol when Addison’s disease is suspected. 3 (Guideline recommendation)
Clinical features that should prompt immediate testing include hyponatremia, hyperkalemia, or unexplained hypotension. 3 (Clinical trigger)