Short answer: The Aldactone label has no missed-dose instructions and no patient leaflet. It describes tablets taken once daily or in divided doses, with or without food but consistently with respect to food. Spironolactone itself has a half-life of 1.4 hours, while its active breakdown products last about 14 to 17 hours. Ask your prescriber or pharmacist what to do.
| Situation | What the label says |
|---|---|
| Schedule | Once daily or in divided doses, consistently with respect to food (2.1 to 2.4) |
| Missed-dose rule | None in the label |
| Half-life | Spironolactone 1.4 hours; its metabolites 13.8 to 16.5 hours (12.3) |
No. We checked the Aldactone prescribing information from Pfizer on DailyMed. It has no missed-dose section and no patient leaflet. Section 2.1 says it can be taken with or without food, but consistently with respect to food.
Section 12.3 gives a mean half-life of 1.4 hours for spironolactone and 13.8 to 16.5 hours for its metabolites, including canrenone. Most of the effect between doses comes from these metabolites.
Aldactone is labeled for heart failure, high blood pressure, edema and primary hyperaldosteronism (section 1). Use for acne or hair loss is outside the label, so the label has no schedule or missed-dose rule for it.
This page summarizes FDA labeling. It is not personalized medical advice; confirm what to do with your prescriber or pharmacist.