Are inhalers such as Incruse (umeclidinium bromide) contraindicated in hypertrophic obstructive cardiomyopathy?

Incruse is NOT contraindicated in hypertrophic obstructive cardiomyopathy

Incruse (umeclidinium bromide), a long-acting muscarinic antagonist (LAMA) inhaler, does not have a specific contraindication for use in patients with hypertrophic obstructive cardiomyopathy (HOCM). However, caution is warranted due to the anticholinergic mechanism of action and potential cardiovascular effects.

FDA Label Contraindications

According to the FDA prescribing information, Incruse is contraindicated only in 1:

• Severe hypersensitivity to milk proteins
• Hypersensitivity to umeclidinium or any excipients

HOCM is not listed as a contraindication.

Mechanistic Considerations in HOCM

The concern with anticholinergics in HOCM relates to their potential cardiovascular effects, though the mechanism differs from drugs explicitly warned against in HOCM guidelines:

What the HCM Guidelines Actually Prohibit

The 2011 ACCF/AHA guidelines clearly identify potentially harmful drugs in obstructive HCM 2:

Class III (Harm) - Avoid these:

• Pure vasodilators and high-dose diuretics (worsen obstruction)
• Dihydropyridine calcium channel blockers like nifedipine (vasodilation increases gradient)
• Positive inotropes (dopamine, dobutamine, norepinephrine - increase contractility and obstruction)
• Digitalis in absence of atrial fibrillation

Anticholinergic bronchodilators are NOT mentioned in these guidelines.

Why Anticholinergics Differ

Inhaled anticholinergics like umeclidinium:

• Have minimal systemic absorption (quaternary ammonium compound)
• Do not cause vasodilation or positive inotropy
• Do not directly worsen left ventricular outflow tract (LVOT) obstruction through the mechanisms that make vasodilators harmful

Practical Clinical Approach

For patients with HOCM requiring COPD treatment:

1. Incruse can be used - there is no absolute contraindication

2. Monitor for:

   • Tachycardia (anticholinergics can increase heart rate, which may worsen symptoms in HOCM)
   • Worsening dyspnea or chest pain
   • Changes in exercise tolerance

3. Optimize HOCM management first 2, 3:

   • Ensure beta-blockers are at target dose (heart rate <60-65 bpm)
   • Consider verapamil if beta-blockers contraindicated
   • Avoid dehydration (maintain preload)

4. Consider beta-blocker timing: If the patient is on beta-blockers for HOCM (Class I recommendation 2), these may partially offset any tachycardic effects from the anticholinergic

Cardiovascular Safety Data

Real-world evidence for umeclidinium shows acceptable cardiovascular safety 4:

• Noninferior to tiotropium for composite cardiovascular endpoints (MI, stroke, heart failure, sudden cardiac death)
• Low incidence rates of cardiovascular events across cohorts
• No specific signals for worsening obstructive cardiomyopathy

Key Caveats

Watch for drug interactions:

• Avoid combining with other anticholinergic medications 1
• Be cautious with narrow-angle glaucoma and urinary retention 1

The 2024 AHA/ACC HCM guidelines 5, 6 emphasize treating comorbidities per existing guidelines - this supports using appropriate COPD therapy when indicated, as untreated COPD significantly worsens outcomes 7.

Bottom line: Use Incruse in HOCM patients with COPD when clinically indicated, ensure optimal HOCM medical management (especially beta-blockade), and monitor for symptom changes. The theoretical concern about tachycardia is manageable and does not constitute a contraindication.