What are the contraindications for an elderly patient with occasional Atrial Fibrillation (AFib) and Heart Failure with reduced Ejection Fraction (HFrEF) taking 100 mg amiodarone and 5 mg bisoprolol once per day?

Contraindications for Amiodarone and Bisoprolol in Elderly Patients with AFib and HFrEF

Both amiodarone and bisoprolol are contraindicated in patients with cardiogenic shock, marked sinus bradycardia, and second- or third-degree AV block without a functioning pacemaker. 1, 2

Absolute Contraindications

For Amiodarone (100 mg daily):

• Cardiogenic shock 1
• Marked sinus bradycardia (typically HR <50 bpm) 1
• Second- or third-degree AV block unless a functioning pacemaker is present 1
• Known hypersensitivity to amiodarone, iodine, or any component 1

For Bisoprolol (5 mg daily):

• Cardiogenic shock 2
• Overt cardiac failure (decompensated heart failure) 2
• Second- or third-degree AV block 2
• Marked sinus bradycardia 2

Critical Monitoring Requirements and Relative Contraindications

Amiodarone-Specific Concerns in Elderly:

Amiodarone requires extensive monitoring due to multiple organ toxicities that are particularly problematic in elderly patients. 3

• Pulmonary fibrosis risk - monitor with baseline and periodic chest imaging and pulmonary function tests 3, 4
• Thyroid dysfunction (both hyper- and hypothyroidism) - check TSH, free T4 at baseline and every 3-6 months 3, 4
• Hepatotoxicity - monitor transaminases at baseline and periodically 3, 4
• Neurological toxicity including tremor, ataxia, peripheral neuropathy, cognitive impairment 3, 4
• QTc prolongation - avoid if baseline QTc >500 ms or with other QT-prolonging drugs 3
• Corneal deposits and optic neuritis - ophthalmologic monitoring recommended 3

Beta-Blocker Concerns in Elderly with HFrEF:

Bisoprolol should not be initiated during acute decompensation but is recommended once the patient is stabilized. 3

• Avoid in decompensated heart failure - wait until euvolemic and hemodynamically stable 3, 2
• Bradycardia risk - monitor heart rate; avoid if resting HR <55 bpm 3, 5
• Hypotension - ensure systolic BP >90 mmHg before dosing 3, 5
• Bronchospasm - use with caution in COPD/asthma (bisoprolol is cardioselective, which is advantageous) 3
• Peripheral arterial disease - may worsen claudication 3

Drug Interactions Requiring Caution

Amiodarone Interactions:

• Warfarin - significantly increases INR; requires dose reduction of warfarin by 30-50% 4, 6
• Statins (simvastatin, atorvastatin) - increased risk of myopathy; limit simvastatin to 20 mg daily 4
• Digoxin - increases digoxin levels; reduce digoxin dose by 50% 4, 6
• Other QT-prolonging drugs - avoid combination due to proarrhythmia risk 3

Combined Beta-Blocker and Amiodarone:

• Additive bradycardia and AV block risk - monitor ECG closely 3
• Enhanced negative chronotropic effects - particularly concerning in elderly 3

Conditions Requiring Extreme Caution (Not Absolute Contraindications)

In elderly patients ≥75 years, both drugs require heightened vigilance due to age-related pharmacokinetic changes. 3

• Renal impairment - bisoprolol requires dose adjustment; amiodarone may cause renal dysfunction 3
• Hepatic impairment - both drugs metabolized hepatically; monitor liver function 3
• Electrolyte disturbances - hypokalemia and hypomagnesemia increase amiodarone's proarrhythmic risk 3
• Sinus node dysfunction - both drugs can worsen; consider pacemaker if symptomatic 3

Special Considerations for This Combination

The combination of amiodarone 100 mg and bisoprolol 5 mg is reasonable for this patient population, but requires careful monitoring. 3

• Amiodarone is recommended for HFrEF patients with AFib requiring rhythm control when structural heart disease is present 3, 7
• Bisoprolol is one of three beta-blockers proven to reduce mortality in HFrEF 3, 5
• Maintenance amiodarone should not exceed 200 mg/day - the 100 mg dose is appropriate 3
• Rate control target is resting HR <80 bpm for symptomatic management 3, 5

Common Pitfalls to Avoid

• Do not use nondihydropyridine calcium channel blockers (diltiazem, verapamil) in decompensated HFrEF - they are contraindicated 3
• Do not use dronedarone for rate control in permanent AFib - increases cardiovascular mortality 3
• Do not use class I antiarrhythmics (flecainide, propafenone) in patients with HFrEF or coronary disease 3
• Avoid amiodarone in pre-excitation syndromes (WPW) with AFib - may accelerate ventricular rate 3