Фоскарнет натрия

Описание

Foscamet sodium is a new, injectable antiviral agent useful in the treatment of severe cytomegalovirus retinitis in immunodepressed patients. Foscarnet sodium acts by inhibiting viral-specific DNA polymerases; its side-effects include decreased hemoglobin levels and acute tubular necrosis.

Использование

Inhibits viral DNA polymerase and reverse transcriptase.
Foscarnet is the only antiviral approved by the FDA for the treatment of acyclovir-resistant HSV infections, a growing problem in the AIDS population. Foscarnet does not require HSV-encoded thymidine kinase. Foscarnet therapy reduces the healing time, pain, and viral shedding. It is administered intravenously, 40 mg/kg every 8 to 12 hours within 7 to 10 days in patients suspected of having acyclovir-resistant herpes simplex infection. Foscarnet is administered for 10 days. Associated side effects include azotemia secondary to nephrotoxicity, hyperphosphatemia, hypocalcemia, anemia, nausea, vomiting, and genital ulceration. Patients may eventually develop resistant strains. Preliminary trials indicate that topical 1%foscarnet cream may have some benefit for the treatment of acyclovir-resistant mucocutaneous HSV infection in patients with AIDS.

Определение

ChEBI: The trisodium salt of phosphonoformic acid. It is used as an antiviral agent in the treatment of cytomegalovirus retinitis (CMV retinitis, an inflamation of the retina that can lead to blindness) and as an alternative to ganciclovir for AIDS patients who r quire concurrent antiretroviral therapy but are unable to tolerate ganciclovir due to haematological toxicity.

Общее описание

pyrophosphateanalog that inhibits replication in herpesviruses(CMV, HSV, and VSV) and retroviruses (HIV).Foscarnet(Foscavir) is taken up slowly by the cells and does not undergosignificant intracellular metabolism. Foscarnet is a reversible,noncompetitive inhibitor at the pyrophosphatebindingsite of the viral DNA polymerase and RT. Theultimate effect is inhibition of the cleavage of pyrophosphatefrom deoxynucleotide triphosphates and a cessation ofthe incorporation of nucleoside triphosphates into DNA(with the concomitant release of pyrophosphate).Becausethe inhibition is noncompetitive with respect to nucleosidetriphosphate binding, foscarnet can act synergistically withnucleoside triphosphate antimetabolites (e.g., zidovudineand didanosine triphosphates) in the inhibition of viral DNAsynthesis. Foscarnet does not require bioactivation by viralor cellular enzymes and, hence, can be effective against resistantviral strains that are deficient in virally encoded nucleosidekinases.
Foscarnet is a second-line drug for the treatment of retinitiscaused by CMV in patients with AIDS. The drug causesmetabolic abnormalities including increases or decreases inblood Ca2 levels. Nephrotoxicity is common, and this sideeffect precludes the use of foscarnet in other infections causedby herpesvirus or as single-agent therapy for HIV infection.Foscarnet is an excellent ligand for metal ion binding,which undoubtedly contributes to the electrolyte imbalancesobserved with the use of the drug.Hypocalcemia, hypomagnesemia,hypokalemia, and hypophosphatemia and hyperphosphatemiaare observed in patients treated with foscarnet.Side effects such as paresthesias, tetani, seizures, and cardiacarrhythmias may result.

Клиническое использование

Foscarnet sodium was approved by the U.S. FDA for the treatment of CMV retinitis in patients with AIDS. In combination with ganciclovir, the results have been promising, even in progressive disease with ganciclovir-resistant strains. Foscarnet sodium also is effective in the treatment of mucocutaneous diseases caused by acyclovir-resistant strains of HSV and VZV in patients with AIDS. Foscarnet sodium is administered IV at 60 mg/kg three times a day for initial therapy and at 90 to 120 mg/kg daily for maintenance therapy. The plasma-half life is 3 to 6 hours. Foscarnet sodium penetrates into the CSF and the eye. The drug is neurotoxic, and common adverse effects include phlebitis, anemia, nausea, vomiting, and seizures. Foscarnet sodium carries the risk of severe hypocalcemia, especially with concurrent use of IV pentamidine. Foscarnet sodium used with zidovudine (ZDV) has an additive effect against CMV and acts synergistically against HIV.