Digoxin and Spironolactone interaction
Digoxin 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 Digoxin label · effective 2025-04-10
…Conivaptan 33% 43% Diltiazem 20% NA Indomethacin 40% NA Mirabegron 29% 27% Nefazodone 27% 15% Nifedipine 45% NA Propantheline 24% 24% Quinine NA 33% Rabeprazole 29% 19% Saquinavir 27% 49% Spironolactone 25% NA Telmisartan 20 to 49% NA Ticagrelor 31% 28% Tolvaptan 30% 20% Trimethoprim 22 to 28% NA Digoxin Concentrations Increased, but Magnitude is Unclear Alprazolam,…
Serum potassium levels should be carefully monitored when digoxin is given to patients at high risk of hypokalemia ( e.g. , those receiving diuretics, corticosteroids, or other drugs that commonly lead to potassium loss; those with gastrointestinal losses through diarrhea, vomiting, or nasogastric suction; or those with potassium-losing endocrinopathies or nephropathies).
In some assays, spironolactone, canrenone and potassium canrenoate may be falsely detected as digoxin, at levels up to 0.5 ng/mL.
Spironolactone and DLIS are much more extensively protein-bound than digoxin.
As a result, assays of free digoxin levels in protein-free ultrafiltrate (which tend to be about 25% less than total levels, consistent with the usual extent of protein binding) are less affected by spironolactone or DLIS.
From the Spironolactone label · effective 2026-08-26
Digoxin Spironolactone and its metabolites increase the apparent exposure to digoxin.
Reduce digoxin concentrations by decreasing the dose by approximately 15-30% or by modifying the dosing frequency and continue monitoring [see Clinical Pharmacology ( 12.3 )] .
Digoxin: Spironolactone oral suspension can interfere with radioimmunologic assays of digoxin exposure ( 7.4 )
In patients taking concomitant digoxin, measure serum digoxin concentrations before initiating spironolactone using an assay that does not interact with spironolactone.
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.