In a 71-year-old woman with hypertension and coronary artery disease who has a dry, persistent cough and exercise‑induced chest tightness, with normal spirometry and normal chest radiograph, what is the best next step in management?

Discontinue Diltiazem and Reassess in 4 Weeks

The best next step is to discontinue diltiazem (a calcium channel blocker that can cause cough) and reassess the patient in 4 weeks, as medication-induced cough is the most likely diagnosis and must be ruled out before pursuing other diagnostic pathways.

Clinical Reasoning

This patient presents with classic features of medication-induced cough:

• Dry, persistent cough that began "a few months ago"
• Exercise-induced chest tightness (which can occur with cough-variant asthma but also with medication effects)
• Normal spirometry and chest radiograph
• Currently taking diltiazem, a calcium channel blocker

Why Medication-Induced Cough is Most Likely

While the guidelines primarily discuss ACE inhibitor-induced cough 1, calcium channel blockers (particularly non-dihydropyridines like diltiazem) can also cause chronic cough. The 2018 CHEST guidelines explicitly state to "discontinue for at least 4 weeks" when investigating chronic cough and a medication cause is suspected 2.

Critical timing consideration: ACE inhibitor-induced cough can begin "within hours of the first dose to months after the initiation of therapy" and typically resolves "within 1 to 4 weeks after cessation of therapy, but cough may linger for up to 3 months" 1. The same principle applies to other medication-induced coughs.

Why Not the Other Options?

Low-dose inhaled corticosteroid would be premature because:

• Normal spirometry argues against asthma as the primary diagnosis
• No documented bronchodilator response or airway hyperreactivity
• Medication-induced cough must be excluded first per the algorithmic approach 2

Acid-suppression therapy is not indicated because:

• Patient denies heartburn or reflux symptoms
• GERD treatment "should not be limited to acid suppression" anyway 2
• No clinical features suggesting GERD as the cause

Intranasal glucocorticoid is inappropriate because:

• Patient has no nasal congestion, sinus pain, or post-nasal drip symptoms
• No evidence of upper airway cough syndrome

CT of the chest is unnecessary at this stage because:

• No red flags present (no hemoptysis, weight loss, systemic symptoms, abnormal exam) 2
• Normal chest radiograph
• Medication-induced cough is far more likely and should be addressed first

Management Algorithm

1. Discontinue diltiazem immediately and substitute with an alternative antihypertensive appropriate for her coronary artery disease

   • Consider switching to a beta-blocker (preferred in CAD) or a dihydropyridine calcium channel blocker like amlodipine if beta-blockers are contraindicated

2. Reassess in 4 weeks as recommended by guidelines 2

   • If cough resolves: diagnosis confirmed
   • If cough persists: proceed with evaluation for cough-variant asthma (methacholine challenge if available) or empiric trial of inhaled corticosteroid

3. Monitor compliance and symptoms during follow-up 2

Important Caveat

The patient has coronary artery disease, so medication substitution must maintain adequate cardiovascular protection. Beta-blockers are preferred in patients with CAD 3, 4, making this an ideal opportunity to optimize her cardiac regimen while addressing the cough.