Crystalluria acyclovir

Acyclovir is available for use orally, topically, and par-enterally (for IV use). When given IV, acyclovir can cause phlebitis, lethargy, confusion, tremors, skin rashes, nausea, and crystalluria Side effects when given orally include nausea, vomiting, diarrhea, headache, dizziness, and skin rashes. Topical administration causes transient burning, stinging, and pruritus. 

ACYCLOVIR When given IV, acyclovir can cause crystal-luria (presence of crystals in the urine) and mental confusion. The nurse helps the patient maintain adequate hydration to prevent crystalluria by encouraging the patient to drink 2000 to 3000 mL of fluid each day (if the disease condition permits). In addition, the nurse should give careful attention to assessing the mental status of the patient. 

Blossom AP, Cleary JD, Daley WP. Acyclovir-induced crystalluria. Ann Pharmacother 2002 36(3) 526. 

In an in vivo animal study, at doses not causing crystalluria or tissue crystal deposition, short term exposure to acyclovir caused increased renal vasoconstriction and an associated fall in renal blood flow and single nephron plasma flow [22]. Longer-term treatment resulted in a fall in glomerular ultrafiltration coefficient. Thus, it is not clear whether the pathogenesis of acyclovir-induced AKI in humans reflects an obstructive nephropathy from intratubular precipitation of acyclovir, a hemodynamic response, or a type of toxic, immunologic, or hypersensitivity reaction. It is also possible that more than one process may be involved. 

Valacyclovir is the L-valyl ester of acyclovir, with oral bioavailability three to five times that of oral acyclovir. Following ingestion, it is rapidly converted by intestinal and hepatic hydrolases to acyclovir. Valacyclovir has gastrointestinal and neurological side effects similar to those seen with acyclovir. To date, significant nephrotoxicity and crystalluria as seen with acyclovir has only rarely been reported with... 

Potter JL, Krill CE. Acyclovir crystalluria. Pediatr Infect Dis 1986 5 710-712. 

Acyclovir is eliminated in the urine by glomerular filtration and by active tubular secretion, which is inhibited by probenecid. Nephrotoxic effects, including hematuria and crystalluria, are enhanced in patients who are dehydrated or who have preexisting renal dysfunction. Adequate hydration is equally important in the case of indinavir, since it causes nephrolithiasis. However, more than 80% of a dose of indinavir is eliminated via hepatic metabolism. The answer is (A). 

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