Answer
Probenecid and cimetidine increase blood exposure to aciclovir (AUC) by competing for active renal tubular secretion and reducing its renal clearance, but no dosage adjustment is necessary because aciclovir has a wide therapeutic index.
Sources for this answer
- Zovirax SuspensionGlaxoSmithKline UK · emc · SmPC §4.5 Interaction with other medicinal products · Version 28Document updated
Sources checked