OBJECT DRUGS

• Procainamide (Pronestyl)

PRECIPITANT DRUGS

• Cimetidine (Tagamet, etc.)
• Co-trimoxazole (Bactrim, Septra)
• Ketoconazole (Nizoral, etc.)
• Levofloxacin (Levaquin, etc.)
• Triamterene (Dyrenium)

Comment:

The renal clearance of procainamide may be reduced by these drugs, resulting in elevated procainamide concentrations, particularly in patients with renal dysfunction. Pending more study, other drugs reported to inhibit cationic tubular secretion (e.g., amiodarone, dofetilide, diltiazem, metformin, and verapamil) should be used with careful monitoring in patients taking procainamide.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative:
• Cimetidine: Other H₂-receptor antagonists such as famotidine (Pepcid), nizatidine (Axid), and ranitidine (Zantac) could be used instead of cimetidine.
• Triamterene: Spironolactone (Aldactone) or amiloride (Midamor) could be used as a potassium-sparing diuretic.
• Monitor: Be alert for increased procainamide effects (e.g., prolonged QRS or QTc intervals) in patients taking drugs that are known to reduce cationic renal clearance.