Losartan and Spironolactone and hydrochlorothiazide interaction
Losartan and Spironolactone and hydrochlorothiazide: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Losartan (COZAAR) label · effective 2026-01-20
Hypotension in Volume- or Salt-Depleted Patients In patients with an activated renin-angiotensin system, such as volume- or salt-depleted patients (e.g., those being treated with high doses of diuretics), symptomatic hypotension may occur after initiation of treatment with COZAAR.
NSAIDs: Increased risk of renal impairment and reduced diuretic, natriuretic, and antihypertensive effects.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including losartan)…
Renal Function Deterioration Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system and by diuretics.
Drug Interactions No clinically significant drug interactions have been found in studies of losartan potassium with hydrochlorothiazide, digoxin, warfarin, cimetidine and phenobarbital.
From the Spironolactone and hydrochlorothiazide label · effective 2026-02-10
…spironolactone and hydrochlorothiazide tablets with the following drugs or potassium sources may lead to severe hyperkalemia: • other potassium-sparing diuretics • ACE inhibitors • angiotensin II receptor antagonists • aldosterone blockers • non-steroidal anti-inflammatory drugs (NSAIDs), e.g., indomethacin • heparin and low molecular weight heparin • other drugs…
Thiazides may add to or potentiate the action of other antihypertensive drugs.
Drug interactions ACE inhibitors, Angiotensin II receptor antagonists, aldosterone blockers, potassium supplements, heparin, low molecular weight heparin, and other drugs known to cause hyperkalemia: Concomitant administration may lead to severe hyperkalemia.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.