Switch Losartan to Entresto (Sacubitril/Valsartan)
The next step is to switch losartan to sacubitril/valsartan (Entresto). This patient with new-onset HFrEF (EF 35%) is already on several appropriate medications but is missing the most critical evidence-based therapy for reducing mortality and hospitalization in heart failure with reduced ejection fraction.
Rationale for Sacubitril/Valsartan
The 2021 ACC Expert Consensus Decision Pathway explicitly recommends angiotensin receptor-neprilysin inhibitors (ARNIs) as first-line therapy for HFrEF, alongside beta-blockers, mineralocorticoid receptor antagonists, and SGLT2 inhibitors 1. The PARADIGM-HF trial demonstrated that sacubitril/valsartan reduced the composite endpoint of cardiovascular death or HF hospitalization by 20% compared to enalapril, with benefits seen for both death and hospitalization 2. This patient is currently on losartan (an ARB), making the transition to sacubitril/valsartan straightforward and guideline-recommended 1.
Key implementation points:
- Ensure a 36-hour washout period from losartan before initiating sacubitril/valsartan to minimize angioedema risk 1
- Start at 24/26 mg or 49/51 mg twice daily, targeting 97/103 mg twice daily 1, 3
- Monitor blood pressure, renal function, and potassium after initiation 1
Why Not the Other Options?
Option 1: Switch Dapagliflozin to Sitagliptin - INCORRECT
This would be a significant step backward. Dapagliflozin is already optimal therapy for this patient. SGLT2 inhibitors like dapagliflozin are now cornerstone therapy for HFrEF, reducing mortality and hospitalization regardless of diabetes status 1, 4. The DAPA-HF trial showed dapagliflozin reduced worsening heart failure or cardiovascular death by 27% (HR 0.73,95% CI 0.60-0.88) in patients without diabetes 4. Sitagliptin (a DPP-4 inhibitor) has no proven benefit in heart failure and would eliminate a life-saving medication 5.
Option 3: Switch Carvedilol to Long-Acting Metoprolol - INCORRECT
Carvedilol is already an evidence-based beta-blocker for HFrEF. Both carvedilol and metoprolol succinate (extended-release) have proven mortality benefits in HFrEF 6, 2. The 2021 guidelines state "only evidence-based beta-blockers should be used" and list both carvedilol and metoprolol succinate as appropriate 1. Switching between these agents offers no additional benefit and delays optimization of other therapies. The patient should continue carvedilol and focus on adding missing guideline-directed medical therapy.
Option 4: Add HCTZ to Lasix - INCORRECT
While combination diuretic therapy can be considered for refractory congestion, this is not the priority after initial diuresis. The 2021 ACC guidelines recommend adding thiazide diuretics only when reaching high doses of loop diuretics (equivalent to furosemide 80 mg twice daily) 1. The question states the patient "already received diuretics," suggesting decongestion has been achieved. The focus should now shift to disease-modifying therapy that reduces mortality and prevents rehospitalization, not further diuresis.
Missing Therapy: Mineralocorticoid Receptor Antagonist
After switching to sacubitril/valsartan, this patient also needs a mineralocorticoid receptor antagonist (MRA) such as spironolactone or eplerenone 1, 2. The 2022 AHA/ACC/HFSA guidelines recommend four foundational drug classes for HFrEF: ARNI (or ACE-I/ARB), beta-blocker, MRA, and SGLT2 inhibitor 7. This patient currently has only two of the four (beta-blocker and SGLT2 inhibitor).
Implementation Algorithm
Step 1: Stop losartan and wait 36 hours
Step 2: Initiate sacubitril/valsartan 24/26 mg or 49/51 mg twice daily
Step 3: Monitor BP, creatinine, and potassium at 1-2 weeks
Step 4: Uptitrate sacubitril/valsartan every 2-4 weeks to target dose 97/103 mg twice daily 1
Step 5: Add spironolactone 12.5-25 mg daily (if not contraindicated by hyperkalemia or severe renal dysfunction) 1, 2
Step 6: Continue dapagliflozin, carvedilol, and other appropriate therapies
Critical Pitfalls to Avoid
- Do not combine sacubitril/valsartan with ACE inhibitors due to increased angioedema risk 1
- Do not delay ARNI initiation waiting for "stable" patients—the 2025 European consensus supports early initiation even in hospitalized patients after decongestion 8
- Do not discontinue dapagliflozin—it provides independent mortality benefit and should be continued alongside ARNI 1, 4
- Monitor for hypotension but recognize that asymptomatic low blood pressure does not require dose reduction if the patient is clinically stable 8