title: The effect of acyclovir on the tubular secretion of creatinine in vitro.
abstract: BACKGROUND
  While generally well tolerated, severe nephrotoxicity has been observed in some children receiving acyclovir. A pronounced elevation in plasma creatinine in the absence of other clinical manifestations of overt nephrotoxicity has been frequently documented. Several drugs have been shown to increase plasma creatinine by inhibiting its renal tubular secretion rather than by decreasing glomerular filtration rate (GFR). Creatinine and acyclovir may be transported by similar tubular transport mechanisms, thus, it is plausible that in some cases, the observed increase in plasma creatinine may be partially due to inhibition of tubular secretion of creatinine, and not solely due to decreased GFR. Our objective was to determine whether acyclovir inhibits the tubular secretion of creatinine.
  
  
  METHODS
  Porcine (LLC-PK1) and human (HK-2) renal proximal tubular cell monolayers cultured on microporous membrane filters were exposed to [2-14C] creatinine (5 μM) in the absence or presence of quinidine (1E+03 μM), cimetidine (1E+03 μM) or acyclovir (22-89 μM) in incubation medium.
  
  
  RESULTS
  Results illustrated that in evident contrast to quinidine, acyclovir did not inhibit creatinine transport in LLC-PK1 and HK-2 cell monolayers.
  
  
  CONCLUSIONS
  The results suggest that acyclovir does not affect the renal tubular handling of creatinine, and hence, the pronounced, transient increase in plasma creatinine is due to decreased GFR, and not to a spurious increase in plasma creatinine.
authors.affiliation: Division of Clinical Pharmacology and Toxicology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada.
authors.forename: Patrina
authors.initials: P
authors.lastname: Gunness
authors.forename: Katarina
authors.initials: K
authors.lastname: Aleksa
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
mesh_terms: D000212:Acyclovir / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D002648:Child; D003404:Creatinine / Q000378:metabolism*; D006801:Humans; D007275:Injections, Intravenous; D007684:Kidney Tubules / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D034421:Sus scrofa; D019789:Tetraethylammonium / Q000378:metabolism
chemical_list: D019789:Tetraethylammonium; D003404:Creatinine; D000212:Acyclovir