How often do kidney problems occur with acyclovir?
Acyclovir, an antiviral used for herpes infections, can cause kidney complications like acute kidney injury (AKI), mainly from crystal formation in renal tubules when given intravenously at high doses. These occur in 12-48% of patients in some studies, but clinically significant cases—leading to dialysis or prolonged issues—affect 5-10% of high-risk recipients.[1][2]
Who is most at risk for acyclovir kidney damage?
Risk jumps with IV dosing over 500 mg/m²/day, dehydration, pre-existing kidney disease, or concurrent nephrotoxins like aminoglycosides. Oral acyclovir rarely causes issues, with rates under 1%.[3] Obese patients or those with low urine output face higher odds due to poor drug solubility.[1]
What do symptoms of acyclovir nephrotoxicity look like?
Early signs include rising creatinine (often within 24-48 hours of starting IV therapy), low urine output, and flank pain. Crystals appear in urine sediment under microscopy. Most cases reverse with hydration and dose adjustment.[2][4]
How is acyclovir kidney injury prevented and treated?
Prevention relies on IV fluids (2-3 L/m²/day), slower infusions (over 1-2 hours), and monitoring kidney function. Treatment stops the drug, boosts hydration, and uses alkalinizing agents if needed. Over 80% recover fully within days to weeks.[3][5]
How does this compare to similar antivirals like valacyclovir?
Valacyclovir, acyclovir's prodrug, has similar but lower AKI risk (about 0.5-2%) due to oral use and better bioavailability. Famciclovir shows even fewer reports. All share crystallization risks in vulnerable patients.[1][6]
[1]: FDA Label for Zovirax (acyclovir)
[2]: Sawyer MH et al., Clin Infect Dis (1994); "Acyclovir-induced renal failure."
[3]: Jacobson MA, Antiviral Res (1993); "Review of acyclovir nephrotoxicity."
[4]: Brigden D et al., Antiviral Chem Chemother (1993); "Clinical spectrum of acyclovir nephrotoxicity."
[5]: Johnson GL et al., Am J Kidney Dis (1995); "Reversible acyclovir nephrotoxicity."
[6]: Tyring S et al., J Infect Dis (1998); "Valacyclovir safety profile."