What Are They For?
Blood pressure control and, for ACE inhibitors, ARBs, and especially ARNI, a core "four pillar" heart failure medication that reduces strain on the heart and helps you live longer with HFrEF (heart failure with reduced ejection fraction — a heart with weak contraction, ejection fraction under 40%).
How They Help (In Plain Terms)
These medications block a hormone system (the renin-angiotensin system) that, left unchecked, constricts blood vessels and causes the body to retain salt and water — both of which increase the heart's workload. ACE inhibitors and ARBs work at slightly different points in this system; ARBs are often used when ACE inhibitors cause a specific cough side effect. ARNI combines an ARB-like effect with an additional mechanism that boosts natural, protective hormones — which is why ARNI is now often preferred over ACE-I/ARB alone for HFrEF specifically, when appropriate and tolerated.
Common Examples
ACE inhibitors:
- Lisinopril (Prinivil, Zestril)
- Enalapril (Vasotec)
- Ramipril (Altace)
- Benazepril (Lotensin)
- Captopril (Capoten)
ARBs:
- Losartan (Cozaar)
- Valsartan (Diovan)
- Candesartan (Atacand)
- Irbesartan (Avapro)
- Olmesartan (Benicar)
ARNI:
- Sacubitril/valsartan (Entresto) — the only medication currently in this combination class
Common Side Effects to Know
- Dizziness or lightheadedness, especially when starting or increasing the dose
- A dry cough, specifically with ACE inhibitors (less common with ARBs or ARNI)
- Elevated potassium levels, monitored via blood tests
- Changes in kidney function values — usually mild and expected, monitored via blood tests
Practical Tips
- Don't stop abruptly without talking to your care team
- Report a persistent dry cough — switching from an ACE inhibitor to an ARB may be worth considering
- Stay hydrated, but don't overcorrect your fluid intake without your team's guidance
- Avoid NSAIDs, and be cautious with potassium supplements or salt substitutes, since many contain potassium (see Medications & Substances to Avoid)
What Your Care Team Monitors
Blood pressure, and kidney function and potassium levels via blood tests, especially after starting or changing the dose.
Common Questions
Why did my doctor switch me from an ACE inhibitor to ARNI?
ARNI has shown additional benefit specifically in HFrEF beyond ACE-I/ARB alone, so many heart failure patients are transitioned when appropriate.
Is a little dizziness normal when starting this?
Yes, it often improves as your body adjusts, but mention it at your next visit.
Can I take potassium supplements while on this medication?
Generally not without checking with your doctor first — the combination can raise potassium to unsafe levels.
Why does the dose keep going up over time?
For heart failure specifically, these medications are often gradually "titrated" toward a proven target dose over weeks to months, since the higher, evidence-backed doses provide more benefit than a low starting dose alone — your team increases it as your blood pressure and labs allow.