Pediatric Drug Interactions with Cimetidine

• Monitor INR when coadministered with warfarin due to increased anticoagulant effect.
• Assess serum levels or clinical response for theophylline, phenytoin, tricyclic antidepressants, and certain antiarrhythmics.
• Space dosing from agents requiring acidic pH (ketoconazole, atazanavir) to maintain efficacy.