What is the best course of action for a patient who develops a dry cough and itchy raspy throat while taking lisinopril (Angiotensin-Converting Enzyme inhibitor) and is subsequently started on amlodipine (Calcium Channel Blocker) 5mg QD (once daily)?

Management of ACE Inhibitor-Induced Cough with Transition to Amlodipine

Immediate Action: Confirm Appropriate Management

Discontinuing lisinopril was the correct decision, as cessation is the only uniformly effective treatment for ACE inhibitor-induced cough. 1 The cough should resolve within 1-4 weeks, though in some patients resolution may take up to 3 months. 1

Critical Error in Current Management

Switching to amlodipine alone represents suboptimal therapy if this patient has heart failure, hypertension with compelling indications for RAAS blockade, or post-MI status. 2 The preferred alternative is an angiotensin receptor blocker (ARB), not a calcium channel blocker, as ARBs provide equivalent cardiovascular benefits without causing cough. 1, 3

Why ARBs Are Superior to Amlodipine for This Scenario:

• ARBs have cough rates similar to placebo (2-3%) compared to ACE inhibitors (7.9%) because they don't inhibit ACE and therefore don't cause bradykinin accumulation. 3
• ARBs maintain the same cardiovascular protection as ACE inhibitors for heart failure, hypertension, and post-MI patients. 2, 3
• The American College of Chest Physicians gives a Grade A recommendation for switching to an ARB when ACE inhibitor-induced cough occurs. 1

Recommended Management Algorithm

Step 1: Switch to an ARB (Preferred)

Start losartan 25-50 mg once daily as the most studied ARB for patients with ACE inhibitor-induced cough. 3 Alternative ARBs include:

• Candesartan 4-8 mg once daily (can titrate to 32 mg daily) 1, 3
• Valsartan 20-40 mg twice daily (can titrate to 160 mg twice daily) 1, 3

Monitor within 1-2 weeks: blood pressure, renal function (creatinine), and potassium levels. 3

Step 2: If ARB Is Not an Option

Continue amlodipine 5 mg daily, which has demonstrated ability to suppress ACE inhibitor-induced cough in 61% of patients in controlled trials. 1, 3 However, this approach sacrifices the RAAS blockade benefits unless the patient has no compelling indication for such therapy.

Alternative cough suppression strategies (if continuing ACE inhibitor is essential):

• Nifedipine 30 mg daily (51% cough reduction) 1
• Sodium cromoglycate 10 mg inhaled QID 1
• Indomethacin 50 mg BID 1

Step 3: Monitor for Cough Resolution

Expect cough resolution within 1-4 weeks after stopping lisinopril, though up to 3 months is possible. 1, 3 If cough persists beyond 3 months, investigate other causes of chronic cough. 1

Important Clinical Pitfalls to Avoid

Pitfall 1: Assuming All ACE Inhibitors Will Cause Cough

Consider rechallenge with an ACE inhibitor if there's a compelling reason. Approximately 30% of patients with confirmed ACE inhibitor-induced cough do not develop cough on rechallenge. 3 Additionally, 55% of patients who continue ACE inhibitors despite cough experience spontaneous resolution after 3.9 months. 4

Pitfall 2: Assuming ARBs Never Cause Cough

While rare, ARBs can occasionally cause cough (though at rates similar to placebo). 3, 5 One case report documented losartan-induced cough that resolved with enalapril substitution, though this is exceptionally uncommon. 5

Pitfall 3: Missing Angioedema Risk

If the patient had angioedema (not just cough), never use an ACE inhibitor again and use extreme caution with ARBs. 1 Angioedema occurs in <1% of ACE inhibitor users but is life-threatening. 1 The current presentation of dry cough and itchy throat without lip/tongue/facial swelling suggests cough, not angioedema.

Pitfall 4: Discontinuing Beta-Blockers

If this patient has heart failure, do not discontinue beta-blocker therapy when switching from ACE inhibitor to ARB. 2 Both medications work through complementary mechanisms and are essential for mortality reduction. 2

Patient-Specific Considerations

Risk Factors Present in This Patient:

The dry cough with "itchy raspy throat" is classic for ACE inhibitor-induced cough, characterized by a persistent tickling sensation. 1 This occurs in 5-35% of ACE inhibitor users and is:

• More common in women 1
• More common in non-smokers 1
• Not dose-dependent 1
• A class effect (all ACE inhibitors cause it) 1

Monitoring Parameters After ARB Initiation:

• Renal function: Check creatinine within 1-2 weeks; increases >0.3 mg/dL occur in 5-15% of patients with mild-moderate symptoms. 1
• Potassium: Hyperkalemia risk increases with diabetes, renal dysfunction, or concurrent potassium-sparing diuretics. 1
• Blood pressure: Assess for hypotension, especially if patient is volume-depleted. 1