Can Angiotensin Receptor Blockers (ARBs) help with shortness of breath (SOB)?

Can ARBs Help with Shortness of Breath?

Yes, ARBs can help with shortness of breath, but only if the SOB is caused by heart failure with reduced ejection fraction (HFrEF). ARBs reduce mortality and hospitalizations in HFrEF patients, which translates to improvement in heart failure symptoms including dyspnea 1.

When ARBs Are Indicated for SOB

ARBs are specifically recommended as Class I, Level A therapy for patients with:

• Prior or current symptoms of chronic HFrEF (LVEF ≤40%) who are intolerant to ACE inhibitors due to cough or angioedema 1
• Symptomatic heart failure (NYHA Class II-IV) with reduced ejection fraction 1

ARBs have been proven in large randomized controlled trials to reduce mortality and heart failure hospitalizations, which directly impacts symptoms like shortness of breath 1.

Critical Clinical Algorithm

Step 1: Identify the Cause of SOB

• If SOB is from HFrEF → ARBs are appropriate (but ACE inhibitors are preferred first-line) 1
• If SOB is from heart failure with preserved ejection fraction (HFpEF) → ARBs do NOT reduce mortality or morbidity 2
• If SOB is from other causes (COPD, asthma, pulmonary embolism, etc.) → ARBs will NOT help

Step 2: Choose the Right RAAS Inhibitor

The hierarchy for HFrEF treatment is:

1. First choice: ARNI (sacubitril/valsartan) for NYHA Class II-III patients who tolerate ACE inhibitors/ARBs - reduces mortality and morbidity by 20% compared to enalapril 1
2. Second choice: ACE inhibitors - first-line therapy, reduce morbidity and mortality 1, 3
3. Third choice: ARBs - only if ACE inhibitor intolerance (cough in up to 20% of patients, or angioedema in <1%) 1, 3

Step 3: Initiation and Monitoring

• Start ARBs at low doses and titrate upward to doses proven effective in clinical trials 1
• Monitor closely: blood pressure, renal function (serum creatinine/eGFR), and serum potassium (avoid if K+ >5.0 mEq/L) 1, 3
• Check labs 1-2 weeks after initiation, after each dose increase, at 3 months, then every 6 months 1

Important Caveats and Pitfalls

ARBs produce similar hemodynamic and neurohormonal effects to ACE inhibitors but have a significantly lower incidence of cough and angioedema 1, 3. However:

• ARBs are NOT superior to ACE inhibitors for mortality reduction - they are alternatives when ACE inhibitors cannot be tolerated 3, 4
• Do NOT combine ARB + ACE inhibitor routinely - this increases adverse effects (withdrawals due to side effects) without reducing mortality or hospitalizations 1, 2
• Caution with angioedema: Although rare, some patients who developed angioedema with ACE inhibitors can also develop it with ARBs 1
• Wait 36 hours after stopping an ACE inhibitor before starting an ARB to avoid overlapping effects 3

Evidence Quality Note

The recommendation for ARBs in HFrEF is based on multiple large randomized controlled trials showing consistent benefits in reducing heart failure hospitalizations and mortality 1. However, a 2017 meta-analysis found that ACE inhibitors, but not ARBs, significantly reduced all-cause mortality (RR 0.89 vs 1.02), reinforcing that ACE inhibitors should remain first-line therapy 4.

Bottom line: ARBs help SOB only when it's caused by HFrEF, and only after ACE inhibitors have been tried first or are contraindicated. For all other causes of SOB, ARBs provide no benefit.