Eplerenone
2 medicines
Eplerenone is an aldosterone-blocking diuretic used for high blood pressure and heart failure; it can raise blood potassium to dangerous levels, so regular blood tests are required and it must not be combined with strong CYP3A4 inhibitors such as ketoconazole or certain HIV medicines.
Key facts
- Eplerenone (sold as Inspra) is a selective aldosterone blocker, a potassium-sparing type of diuretic used for high blood pressure and heart failure.
- It is taken once or twice daily by mouth, and its full blood-pressure effect can take up to four weeks to show.
- It can raise blood potassium to dangerous levels, hyperkalaemia, so regular blood tests to check potassium and kidney function are required throughout treatment.
- It must not be combined with strong CYP3A4-inhibiting medicines, such as ketoconazole, itraconazole, clarithromycin, or ritonavir, since these sharply raise eplerenone levels and the risk of dangerous potassium rises.
What eplerenone treats
Eplerenone treats high blood pressure and chronic heart failure with reduced heart pumping function, and is used after a heart attack in people who develop heart failure or reduced heart function. It works alongside, not instead of, other heart failure medicines such as ACE inhibitors and beta blockers.
How eplerenone works
Aldosterone is a hormone that tells the kidneys to hold onto salt and water while excreting potassium; in heart failure, aldosterone levels are often higher than normal and contribute to fluid overload and scarring of heart tissue. Eplerenone blocks aldosterone's receptor in the kidney and heart, so the body releases more salt and water while retaining potassium, easing fluid buildup and reducing strain on the heart.
Before you take it
- Do not take it if your blood potassium is already high, or if you have significant kidney impairment; your prescriber will check both before starting.
- Tell your prescriber about all other medicines, especially potassium supplements, salt substitutes, other potassium-sparing diuretics, ACE inhibitors, ARBs, and antifungal or HIV medicines.
- Avoid grapefruit juice in large amounts, since it moderately raises eplerenone levels.
- Tell your prescriber if you have diabetes with kidney involvement, since this increases the risk of high potassium.
Side effects
Common effects include dizziness, headache, fatigue, nausea, and mild increases in blood potassium.
Seek urgent medical care for:
- Muscle weakness, cramping, or an irregular heartbeat, which can signal dangerous potassium levels.
- Severe dizziness or fainting.
- Swelling of the face, lips, or tongue.
- A significant drop in urine output.
Safety essentials
- Blood potassium and kidney function must be checked before starting eplerenone and at regular intervals during treatment, since hyperkalaemia can be serious and sometimes silent until it affects heart rhythm.
- Never combine eplerenone with strong CYP3A4 inhibitors (certain antifungals, some antibiotics, some HIV medicines) or with potassium supplements unless your prescriber has specifically approved it.
- Report any muscle weakness, cramping, or unusual heart rhythm promptly, since these can be early signs of high potassium.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.