Ганцикловир

Описание

Ganciclovir is a parenterally-active antiviral agent indicated for sight- or life-threatening cytomegalovirus (CMV) infections in immunocompromised patients. Its suppressive effects on bone marrow and renal tubular secretion/absorption are reported to present potential limitations on adjunct therapies involving zidovudine, vincristine, adriamycin and amphotericin B. Recently, the emergence of CMV strains resistant to ganciclovir therapy has been reported.

Химические свойства

White Powder

Использование

Ganciclovir is a nucleoside analog structurally related to Acyclovir (A192400). Ganciclovir is an antiviral.

Определение

ChEBI: An oxopurine that is guanine substituted by a [(1,3-dihydroxypropan-2-yl)oxy]methyl group at position 9. Ganciclovir is an antiviral drug used to treat or prevent AIDS-related cytomegalovirus infections.

Показания

Ganciclovir (Cytovene) is an acyclic analogue of 2 deoxyguanosine with inhibitory activity toward all herpesviruses, especially CMV.

Приобретенная устойчивость

Prolonged, repeated courses lead to the selection of resistant strains, occurring in 8% of patients receiving the drug for >3 months. Studies of laboratory-derived resistant strains indicate that drug resistance can result from alterations in the phosphonotransferase encoded by the gene region UL 27, the viral DNA polymerase (gene region UL 54), or both.

Общее описание

Ganciclovir, 9-[(1,3-dihydroxy-2-propoxy) methyl]guanine)or DHPG (Cytovene), is an analog of acyclovir, with an additional hydroxymethyl group on the acyclic side chain.
After administration, similar to acyclovir, ganciclovir isphosphorylated inside the cell by a virally encoded proteinkinase to the monophosphate.Host cell enzymes catalyzethe formation of the triphosphate, which reaches more than10-fold higher concentrations in infected cells than in uninfectedcells.
The clinical usefulness of ganciclovir is limited by thetoxicity of the drug. Ganciclovir causes myelosuppression,producing neutropenia, thrombocytopenia, and anemia.These effects are probably associated with inhibition of hostcell DNA polymerase.Potential central nervous systemside effects include headaches, behavioral changes, and convulsions.Ganciclovir is mutagenic, carcinogenic, and teratogenicin animals.

Фармацевтические приложения

A synthetic 2′-deoxyguanosine nucleoside analog, supplied as the l-valine ester, valganciclovir, for oral administration and as the sodium salt for parenteral use. A slow-release ocular implant device is also available.

Механизм действия

Ganciclovir sodium is an acyclic deoxyguanosine analogue of acyclovir. Ganciclovir inhibits DNA polymerase. Its active form is ganciclovir triphosphate, which is an inhibitor of viral rather than of cellular DNA polymerase. The phosphorylation of ganciclovir does not require a virus-specific thymidine kinase for its activity against CMV. The mechanism of action is similar to that of acyclovir; however, ganciclovir is more toxic than acyclovir to human cells.

Фармаколо?гия

Activation of ganciclovir first requires conversion to ganciclovir monophosphate by viral enzymes: protein kinase pUL97 in CMV or thymidine kinase in HSV. Host cell enzymes then perform two additional phosphorylations. The resultant ganciclovir triphosphate competes with dGTP for access to viral DNA polymerase. Its incorporation into the growing DNA strand causes chain termination in a manner similar to that of acyclovir. Ganciclovir triphosphate is up to 100-fold more concentrated in CMV-infected cells than in normal cells and is preferentially incorporated into DNA by viral polymerase. However, mammalian bone marrow cells are sensitive to growth inhibition by ganciclovir.

Клиническое использование

Intravenous ganciclovir is indicated for the treatment of CMV retinitis in immunocompromised individuals, including those with AIDS, and for the prevention of CMV infection in organ transplant recipients.Oral ganciclovir is less effective than the intravenous preparation but carries a lower risk of adverse effects. It is Intravenous ganciclovir is indicated for the treatment of CMV retinitis in immunocompromised individuals, including those with AIDS, and for the prevention of CMV infection in organ transplant recipients.Oral ganciclovir is less effective than the intravenous preparation but carries a lower risk of adverse effects. It is

Побочные эффекты

Myelosuppression is the most common serious adverse effect of ganciclovir treatment; therefore, patients’ blood counts should be closely monitored. Neutropenia and anemia have been reported in 25 to 30% of patients, and thrombocytopenia has been seen in 5 to 10%. Elevated serum creatinine may occur following ganciclovir treatment, and dosage adjustment is required for patients with renal impairment. In animal studies, ganciclovir causes decreased sperm production, teratogenesis, and tumor formation.

Методы очистки

Recrystallise gangcyclovir from MeOH. Alternatively dissolve 90g of it in 700mL of 2O, filter and cool (ca 94% recovery). UV: max in MeOH 254nm ( 12,880), 270sh nm ( 9,040); its solubility in 2O at 25o is 4.3mg/mL at pH 7.0. ANTIVIRAL. [Ogilvie et al. Can J Chem 60 3005 1982, Ashton et al. Biochem Biophys Res Commun 108 1716 1982, Martin et al. J Med Chem 26 759 1983.]

Меры предосторожности

Ganciclovir interacts with a number of medications,some of which are used to treat HIV or transplant patients.Ganciclovir may cause severe neutropenia whenused in combination with zidovudine. Ganciclovir increasesserum levels of didanosine, whereas probeneciddecreases ganciclovir elimination. Nephrotoxicity mayresult if other nephrotoxic agents (e.g., amphotericin B,cyclosporine, NSAIDs) are administered in conjunctionwith ganciclovir.