Sacubitril/Valsartan: what it does and what to watch
Also known as: ARNI, Angiotensin receptor-neprilysin inhibitor · Angiotensin receptor-neprilysin inhibitor (ARNI) · Updated 2026-08-20 · Educational — not medical advice
In plain language: This medicine combines two actions: one component blocks angiotensin II receptors to relax blood vessels and reduce strain on the heart, while the other blocks an enzyme called neprilysin that normally breaks down natural hormones helping the body clear excess sodium and fluid. Blocking this breakdown boosts the protective effect of those hormones on the heart.
What it's used for
- Treatment of certain types of chronic heart failure
- Reducing the risk of hospitalization and supporting heart function in heart failure with reduced pumping ability
Common side effects
- Dizziness
- Low blood pressure symptoms such as light-headedness
- Cough
- Fatigue
- Nausea
Get medical help if…
Angioedema, a rapid swelling of the face, lips, tongue, or throat that can affect breathing, more likely if switched from an ACE inhibitor without an adequate gap between the two medicines
High potassium levels, particularly with reduced kidney function or other potassium-raising medicines
Worsening kidney function, especially with dehydration or other kidney-affecting medicines
Lab values it can move
Few guides tell you this part: medicines show up in blood work. If you take Sacubitril/Valsartan and a value below looks off on your report, this may be part of the story — never stop a medicine without your doctor.
Potassium levels are checked before starting and periodically during treatment, since this medicine can raise potassium, particularly with reduced kidney function.
PotassiumKidney function is monitored, since this medicine's effect on blood vessels and fluid balance can influence creatinine levels.
CreatinineKidney filtering capacity is tracked over time, guiding dose decisions and helping detect worsening kidney function early.
eGFR (Estimated Glomerular Filtration Rate)Good to know
- This medicine must never be combined with an ACE inhibitor; a gap of at least 36 hours is required when switching between the two because of the risk of serious angioedema
- Not used during pregnancy, as it can cause serious harm to a developing baby; contraception is discussed with anyone who could become pregnant
- Kidney function and potassium levels are checked before starting and periodically during treatment
- Seek emergency care immediately for swelling of the face, lips, tongue, or throat, or sudden difficulty breathing or swallowing
- Blood pressure is monitored closely, especially when starting or increasing the dose
Questions people ask
Why is there a strict gap required when switching from an ACE inhibitor to this medicine?
Both this medicine and ACE inhibitors affect a pathway linked to angioedema, a sudden, potentially dangerous swelling of the face, lips, tongue, or throat. Taking them too close together significantly raises this risk. A gap of at least 36 hours between stopping an ACE inhibitor and starting this medicine allows the earlier medicine to clear and reduces that danger.
Why can't this medicine be used during pregnancy?
Medicines that act on this hormone pathway can seriously harm a developing baby's kidney development and other organ systems, particularly later in pregnancy. Because of this, this medicine is avoided throughout pregnancy, and anyone who could become pregnant while taking it discusses reliable contraception and pregnancy planning with a prescriber before starting or continuing treatment.
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