title: Risk of acute kidney injury from oral acyclovir: a population-based study.
abstract: BACKGROUND
  Intravenous acyclovir-induced acute kidney injury (AKI) from drug crystallization in the renal tubules is described in case reports, review articles, and drug prescribing manuals. Similarly, AKI from oral acyclovir is described in case reports, but the risk in routine practice is unknown.
  
  
  METHODS
  Retrospective population-based cohort study.
  
  
  METHODS
  We studied a large cohort of older patients in Ontario, Canada, receiving new outpatient prescriptions from 1997 to 2011 for oral acyclovir or valacyclovir (which is metabolized to acyclovir). The comparison drug was famciclovir, an antiviral used for indications similar to acyclovir, but with no known renal toxicity.
  
  
  METHODS
  Outpatient prescription for oral acyclovir, valacyclovir, or famciclovir.
  
  
  RESULTS
  The primary outcome was hospital admission with AKI in the 30 days after the initial prescription.
  
  
  METHODS
  We assessed the primary outcome with health care diagnostic codes. In a subpopulation, we assessed AKI using available laboratory serum creatinine measurements.
  
  
  RESULTS
  76,269 patients received acyclovir or valacyclovir and 84,646 received famciclovir. On average, patients were aged 76 [IQR, 71-81] years and prescription duration was 7 days. Acyclovir or valacyclovir use was not associated with a higher risk of hospital admission with AKI (209 [0.27%] events with acyclovir or valacyclovir vs 238 [0.28%] events with famciclovir [relative risk, 0.97; 95% CI, 0.81-1.17]). Results were consistent in adjusted analyses, in all subgroups, and in the subpopulation with laboratory measurements.
  
  
  CONCLUSIONS
  Diagnostic codes had high specificity but low sensitivity and underestimated the incidence of AKI. Only a limited number of patients (n = 2,729) had serum creatinine values available.
  
  
  CONCLUSIONS
  In this population-based study of older adults, oral acyclovir use was not associated with a higher risk of AKI compared to famciclovir.
authors: Division of Nephrology, Western University, London, Ontario, Canada.
authors: Ngan N
authors: NN
authors: Lam
authors: Matthew A
authors: MA
authors: Weir
authors: Zhan
authors: Z
authors: Yao
authors: Peter G
authors: PG
authors: Blake
authors: Michael M
authors: MM
authors: Beyea
authors: Tara
authors: T
authors: Gomes
authors: Sonja
authors: S
authors: Gandhi
authors: Muhammad
authors: M
authors: Mamdani
authors: Ron
authors: R
authors: Wald
authors: Chirag R
authors: CR
authors: Parikh
authors: Daniel G
authors: DG
authors: Hackam
authors: Amit X
authors: AX
authors: Garg
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology*; D000212:Acyclovir / Q000008:administration & dosage / Q000009:adverse effects*; D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000998:Antiviral Agents / Q000008:administration & dosage / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D005260:Female; D006561:Herpes Simplex / Q000188:drug therapy; D006562:Herpes Zoster / Q000188:drug therapy; D006801:Humans; D008297:Male; D009864:Ontario / Q000453:epidemiology; D010045:Outpatients; D011159:Population Surveillance; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000998:Antiviral Agents; D003404:Creatinine; D000212:Acyclovir