China
Africa
Explore chapters and articles related to this topic
Antiviral therapeutics for viral infections of the central nervous system
Published in Avindra Nath, Joseph R. Berger, Clinical Neurovirology, 2020
Acyclovir is widely distributed in various tissues and body fluids. CSF concentrations are about 50% of simultaneous plasma concentrations. The principal route of elimination is by the kidney; 45%–79% of a dose is recovered unchanged, the percentage declining with decreasing creatinine clearance. In patients with renal failure, mean peak plasma concentrations nearly doubled and the elimination half-life increased to 19.5 hours. Dosage reductions are advised for various stages of renal impairment [9]. Less than 1% of a dose of valacyclovir is recovered as unchanged drug in the urine. In multidose studies the amount of acyclovir recovered across dose levels ranged from about 40% to 50%. Between 7% and 12% of the dose is found as the 9-carboxymethoxymethylguanine metabolite. Overall, acyclovir accounts for 80%–85% of total urinary recovery.
Aciclovir and Valaciclovir
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Renee-Claude Mercier, Gregory Mertz
In anuric patients, aciclovir is slowly cleared from the body by nonrenal routes. Studies in humans given radiolabeled aciclovir intravenously showed that 71–99% of an administered dose was excreted in the urine, but up to 14.1% of the dose was excreted in the urine as the inactive metabolite, 9-carboxymethoxymethylguanine (CMMG). Unchanged urinary aciclovir proportions ranged from 62% to 91% of the dose (de Miranda et al., 1982).
Comment on ”Acute Retinal Necrosis: Is the Current Valacyclovir Regimen Adequate?”
Published in Ocular Immunology and Inflammation, 2022
Joanna von Hofsten, Marie Studahl
Increasing the dosage of acyclovir/valacyclovir might result in nephro- and neurotoxicity. Moreover, high serum concentrations of acyclovir as well as its metabolite 9-carboxymethoxymethylguanine (CMMG) are positively correlated with acyclovir-induced neuropsychiatric symptoms (AINS).5,6 Disruption of the blood-brain barrier (BBB) further enhances concentrations of acyclovir and CMMG in the cerebrospinal fluid (CSF).6 Involvement of the optic nerve and retina in ARN suggests classification of this manifestation as a central nervous system disease. We do not have data on BBB disruption in ARN patients, in which case ARN patients could possibly be susceptible for developing AINS.