Chlorothiazide and Spironolactone interaction
Chlorothiazide and Spironolactone: 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 Chlorothiazide (DIURIL) label · effective 2021-11-01
Thiazides may add to or potentiate the action of other antihypertensive drugs.
Lithium generally should not be given with diuretics (see PRECAUTIONS , Drug Interactions ).
Other Antihypertensive Drugs - additive effect or potentiation.
Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity.
Non-steroidal Anti-inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 (COX-2) Inhibitors - In some patients, the administration of a non-steroidal anti-inflammatory agent including a selective COX-2 inhibitor can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics.
From the Spironolactone label · effective 2026-08-26
NSAIDs: May reduce the diuretic, natriuretic and antihypertensive effect of spironolactone oral suspension ( 7.3 )
…drugs that can increase potassium include: ACE inhibitors angiotensin receptor blockers aldosterone blockers non-steroidal anti-inflammatory drugs (NSAIDs) heparin and low molecular weight heparin trimethoprim 7.2 Lithium Like other diuretics, spironolactone oral suspension reduces the renal clearance of lithium, thus increasing the risk of lithium toxicity.
Nonsteroidal Anti-inflammatory Drugs (NSAIDs) In some patients, the administration of an NSAID can reduce the diuretic, natriuretic, and antihypertensive effect of loop, potassium-sparing, and thiazide diuretics.
Therefore, when spironolactone oral suspension and NSAIDs are used concomitantly, monitor closely to determine if the desired effect of the diuretic is obtained [see Clinical Pharmacology ( 12.3 )] .
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.