Drug General Information (ID: DDI8A76C3J)
Drug Name			Cimetidine		Drug Info		Procainamide		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiulcer Agents				Antiarrhythmic Agents
Structure

Mechanism of Cimetidine-Procainamide Interaction (Severity Level: Moderate)
Competitive inhibition of renal tubular secretion Click to Show/Hide Mechanism Graph
Drug Name		Cimetidine				Procainamide
Mechanism		Competitive inhibition of renal tubular secretion of procainamide				Procainamide
Key Mechanism Factor 1
		Factor Name		Renal tubular secretion
		Factor Description		Renal tubular secretion allows selective transfer of substances from the blood around the capillaries into the renal tubules via filtrate. Drug excretion may be reduced when two drugs compete for renal tubular secretion.
Mechanism Description		Decreased elimination of Procainamide caused by Cimetidine mediated competitive inhibition of renal tubular secretion

Recommended Action
Management		If these two drugs are given together, serum procainamide and NAPA levels, ECG changes, and hemodynamic status should be closely monitored. Patients should be advised to promptly notify their physician if they experience drowsiness, dizziness, syncope, confusion, tremor, or palpitations. Famotidine and nizatidine do not appear to interact in this manner and may be considered as alternatives.

References
1	Bauer LA, Black D, Gensler A "Procainamide-cimetidine drug interaction in elderly male patients." J Am Geriatr Soc 38 (1990): 467-9. [PMID: 2329253]
2	Christian CD, Meredith CG, Speeg KV "Cimetidine inhibits renal procainamide clearance." Clin Pharmacol Ther 36 (1984): 221-7. [PMID: 6204803]
3	Higbee MD, Wood JS, Mead RA "Procainamide-cimetidine interaction: a potential toxic interaction in the elderly." J Am Geriatr Soc 32 (1984): 162-4. [PMID: 6693705]
4	Lai MY, Jiang FM, Chung CH, et al "Dose dependent effect of cimetidine on procainamide disposition in man." Int J Clin Pharmacol Ther Toxicol 26 (1988): 118-21. [PMID: 2457561]
5	Rodvold KA, Paloucek FP, Jung D, Gallastegui J "Interaction of steady-state procainamide with H2-receptor antagonists cimetidine and ranitidine." Ther Drug Monit 9 (1987): 378-83. [PMID: 2447687]
6	Somogyi A, McLean A, Heinzow B "Cimetidine-procainamide pharmacokinetic interaction in man: evidence of competition for tubular secretion of basic drugs." Eur J Clin Pharmacol 25 (1983): 339-45. [PMID: 6194997]