Table 4. Important antiarrhythmic drug-drug interactions in elderly patients.

Underlying disease	Drugs	Adverse effects
CHF	Disopyramide, flecainide, sotalol	Decompensation
Cardiac conduction disorders	Class 1 drugs, β and Ca2+ blockers	Heart block
COPD	Sotalol	Bronchospasm
Prostate hypertrophy	Disopryramide	Urinary retention
Hypokalemia	Digoxin	Arrhythmias
CAD	Class 1 drugs	Proarrhythmia
Postural hypotension	β and Ca2+ blockers, quinidine, procainamide	Falls

CHF: congestive heart failure; COPD: chronic obstructive pulmonary disease; CAD: coronary artery disease.