2023 Volume 36 Pages 75-80
Valacyclovir (VACV) is an acyclovir (ACV) prodrug. We here report a case of a healthy girl who developed acute kidney injury (AKI) after taking a regular dose of VACV. A 14-year-old girl, diagnosed with herpes zoster, was prescribed 3,000 mg/day of VACV by her previous doctor. She then complained of headache, neck and back pain, and generalized edema that appeared on the seventh day. After discontinuing the medication, she was admitted to a hospital, where a blood examination indicated an occurrence of renal functional impairment. AKI caused by VACV was suspected, and hemodialysis was performed 5 and 7 days after admission. A renal biopsy performed 10 days after admission revealed extensive vacuolar degeneration and loss of tubular epithelial cells without interstitial mononuclear cell infiltration or crystal formation, suggesting acute tubular necrosis caused by drug-induced toxic injury. Thereafter, the renal function improved, and she was discharged after 21 days of hospitalization. We later requested measurement of ACV blood concentration in a serum sample taken on day 7, which showed an abnormally high ACV level of 10.69 µg/mL (appropriate concentration: 0.8–1.6 µg/mL). This case indicates that VACV may induce kidney injury even with its regular doses in children with normal renal function. It is necessary to provide appropriate guidance regarding side effects and drinking volume when prescribing VACV to patients and to strive for prevention and early detection.
