Two medicines, side by side
Spironolactone vs losartan
Spironolactone and losartan are both labeled for high blood pressure. Drugs@FDA records approvals of spironolactone since 1960 and of losartan since 1995. Pharmacies paid $0.0426 per spironolactone 25 mg tablet and $0.0327 per losartan potassium 50 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, spironolactone is an aldosterone antagonist and losartan an angiotensin 2 receptor blocker.
Check it at the source: the spironolactone FDA label on DailyMed (effective November 28, 2025); the losartan FDA label on DailyMed (effective January 20, 2026).
Highlights of the spironolactone record
Spironolactone (Aldactone) · label of November 28, 2025
Used for
From the label: indicationsALDACTONE is an aldosterone antagonist indicated for: • The treatment of NYHA Class III–IV heart failure and reduced ejection fraction to increase survival, manage edema, and to reduce the need for hospitalization for heart failure ( 1.1 ). • Use as an add-on therapy for the treatment of hypertension, to lower blood pressure. […]
On the market
- Earliest approval on file
- January 21, 1960
- Generic labelers
- 38 labelers
- Pharmacy cost
- $0.0426 per tablet
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 6
Highlights of the losartan record
Losartan (Cozaar) · label of January 20, 2026
FETAL TOXICITY When pregnancy is detected, discontinue COZAAR as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus [see Warnings and Precautions (5.1) ]. WARNING: FETAL TOXICITY See full prescribing information for complete boxed warning. When pregnancy is detected, discontinue COZAAR as soon as possible. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus.
Used for
From the label: indicationsCOZAAR is an angiotensin II receptor blocker (ARB) indicated for: Treatment of hypertension, to lower blood pressure in adults and children greater than 6 years old. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. ( 1.1 ) Reduction of the risk of stroke in patients with hypertension and left ventricular hypertrophy. […]
On the market
- Earliest approval on file
- April 14, 1995
- Generic labelers
- 43 labelers
- Pharmacy cost
- $0.0327 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 77
Source: FDA drug labels via openFDA (Spironolactone label of November 28, 2025, Losartan label of January 20, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do spironolactone and losartan differ on the record?
In FDA's classes, spironolactone is an aldosterone antagonist and losartan an angiotensin 2 receptor blocker.
How each works, in its label's words: Spironolactone, “Spironolactone and its active metabolites are specific pharmacologic antagonists of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent …”; Losartan, “Angiotensin II [formed from angiotensin I in a reaction catalyzed by angiotensin converting enzyme (ACE, kininase II)] is a potent vasoconstrictor, the primary vasoactive hormone of the …”
Half-life, in each label's words: Spironolactone, “The mean half-life values of its metabolites including canrenone, 7-α-(thiomethyl) spirolactone (TMS), and …”; Losartan, “The terminal half-life of losartan is about 2 hours and of the metabolite is about 6-9 hours.”
Only the losartan label carries a boxed warning.
Generics: spironolactone since 1980; losartan since 2010 (Drugs@FDA).
| Spironolactone | Losartan | |
|---|---|---|
| Labeled for | Heart failure, Edema (fluid retention), High blood pressure | High blood pressure, Chronic kidney disease, Stroke prevention |
| Pharmacologic class | Aldosterone Antagonist | Angiotensin 2 Receptor Blocker |
| How it works (label) | Spironolactone and its active metabolites are specific pharmacologic antagonists of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent sodium-potassium exchange site in the distal convoluted … | Angiotensin II [formed from angiotensin I in a reaction catalyzed by angiotensin converting enzyme (ACE, kininase II)] is a potent vasoconstrictor, the primary vasoactive hormone of the renin-angiotensin system, and an important component … |
| Half-life (label) | The mean half-life values of its metabolites including canrenone, 7-α-(thiomethyl) spirolactone (TMS), and 6-β-hydroxy-7-α-(thiomethyl) spirolactone (HTMS) are 16.5, 13.8, and 15 hours, respectively. | The terminal half-life of losartan is about 2 hours and of the metabolite is about 6-9 hours. |
| Earliest approval on file (Drugs@FDA) | January 21, 1960 | April 14, 1995 |
| First generic approved | May 7, 1980 | April 6, 2010 |
| Generic labelers (NDC) | 38 labelers | 43 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.0426 per tablet (Spironolactone 25 mg tablet) | $0.0327 per tablet (Losartan potassium 50 mg tablet) |
| 12-month price change | -14% | +2% |
| Boxed warning | No | Yes |
| Shortage now | A presentation being discontinued | No current entry |
| Recalls recorded | 6 | 77 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 139,757 | 200,566 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
What next?
- Alternatives to spironolactone
- every medicine labeled for the same conditions