Is sublingual captopril (angiotensin-converting enzyme inhibitor) useful for a 62-year-old male patient with congestive heart failure and diabetes mellitus type 2 presenting with acute hypertensive heart failure and pulmonary edema?

Sublingual Captopril Is Not Recommended for Acute Hypertensive Heart Failure with Pulmonary Edema

Sublingual captopril should not be used in this clinical scenario—intravenous nitroglycerin combined with loop diuretics is the evidence-based first-line treatment for acute hypertensive heart failure with pulmonary edema. 1, 2, 3

Why Sublingual Captopril Is Not Appropriate

The 2019 ESC Council on Hypertension guidelines for hypertensive emergencies do not include sublingual captopril in their recommended treatment algorithms for acute cardiogenic pulmonary edema. 1 Instead, nitroprusside is explicitly identified as the drug of choice for acute pulmonary edema caused by hypertensive heart failure, as it acutely lowers both ventricular preload and afterload, with nitroglycerin as a good alternative. 1

The American College of Cardiology recommends sublingual nitroglycerin (0.4-0.6 mg repeated every 5-10 minutes up to four times) followed by intravenous nitroglycerin (starting at 0.3-0.5 μg/kg/min) as the immediate vasodilator therapy for acute pulmonary edema. 2, 3 This should be combined with furosemide 20-80 mg IV administered shortly after diagnosis. 2, 3

The Evidence on Sublingual Captopril

While one 1990 study showed that sublingual captopril 25 mg produced hemodynamic improvements in severe heart failure patients, it had critical limitations for acute use: 4

• Delayed onset of action: 16-22 minutes versus 12-19 minutes for nitroglycerin 4
• Delayed peak effect: 47-84 minutes versus 25-55 minutes for nitroglycerin 4
• This study was conducted in stable chronic heart failure patients (NYHA class III-IV), not in acute hypertensive crisis with pulmonary edema 4

In acute pulmonary edema, minutes matter—the delayed onset makes sublingual captopril unsuitable when rapid blood pressure reduction and preload/afterload reduction are critical. 1, 2

Correct Treatment Algorithm for This Patient

Immediate Management (First 15 Minutes)

• Administer sublingual nitroglycerin 0.4-0.6 mg immediately, repeated every 5-10 minutes up to four times if systolic BP remains adequate 2, 3
• Start IV nitroglycerin at 0.3-0.5 μg/kg/min (or 20 mcg/min, titrating up to 200 mcg/min based on hemodynamic response) 2, 3
• Administer furosemide 20-80 mg IV shortly after establishing the diagnosis 2, 3
• Apply non-invasive positive pressure ventilation (CPAP or BiPAP) immediately—this reduces mortality (RR 0.80) and need for intubation (RR 0.60) 2, 3

Blood Pressure Target

• Reduce BP by approximately 25% during the first hours using IV vasodilators with loop diuretics 3
• The goal is rapid afterload reduction without compromising coronary perfusion 1, 2

If Inadequate Response

• If urine output is <100 ml/h for 1-2 hours, double the loop diuretic dose up to the equivalent of 500 mg furosemide 2
• For refractory cases with systolic BP 70-100 mmHg, consider dobutamine 2-20 mcg/kg/min IV for inotropic support 3

Role of Oral ACE Inhibitors in This Patient

ACE inhibitors like captopril are first-line chronic therapy for heart failure and should be initiated once the patient is stabilized. 1 However:

• Do not start ACE inhibitors during acute pulmonary edema 1
• Wait until congestion is relieved and the patient is euvolemic 1
• Start with captopril 6.25 mg three times daily orally (not sublingual), then titrate to target dose of 50-100 mg three times daily over weeks 1

Critical Cautions for ACE Inhibitor Initiation

This patient requires specialist consultation before starting captopril due to: 1

• Symptomatic hypotension (systolic BP <90 mmHg is a caution) 1
• Diabetes mellitus increases risk of hyperkalemia 1
• Monitor creatinine (acceptable increase up to 50% above baseline or to 3 mg/dl) and potassium (acceptable up to 5.5 mmol/l) 1

Common Pitfall to Avoid

Never use sublingual captopril as acute treatment for hypertensive pulmonary edema—its delayed onset (16-22 minutes to effect, 47-84 minutes to peak) makes it inappropriate when immediate vasodilation is needed. 4 The historical use of sublingual captopril for hypertensive emergencies has been abandoned in modern guidelines in favor of IV agents with predictable, titratable effects. 1