Herpesvirus infections, drugs used

Antiviral Efficacy and Clinical Use. Vidarabine (Vira-A) was the first systemic agent used to treat herpesvirus infections, including CMV, herpes simplex virus, and varicella-zoster virus.42 In the past, this drug was administered by continuous intravenous infusion to treat severe systemic infections caused by these viruses, but systemic use of vidarabine has been replaced by safer and less toxic agents. Vidarabine is currently used primarily to treat local viral infections of the eye (e.g., herpes simplex keratoconjunctivitis) it is applied topically by ophthalmic ointment to treat these infections. 

Over-the-counter products containing colloidal silver or silver salts have been marketed for use in adults and children for a wide variety of diseases, including AIDS, cancer, tuberculosis, malaria, systemic lupus erythematosus, syphilis, scarlet fever, herpesvirus infections, pneumonia, typhoid, tetanus, and many others. The US Food and Drug Administration has issued a ruling that a colloidal silver product for any medical use will first have to be approved by the FDA under drug application procedures (11). 

Acyclovir is an antiviral drug used to treat herpesvirus infection. The basis of its action is that acyclovir resembles part of the guanosine nucleoside and is phosphorylated by the viral enzyme, deoxypyrimidine kinase. The phosphorylated triphosphate form of acyclovir is an inhibitor of the herpesvirus DNA polymerase. A related compound, ganciclovir, H2N works similarly. Uninfected cells do not efficiently phosphorylate acyclovir and ganciclovir, so DNA replication and vims growth are inhibited selectively in infected cells. 

Cytarabine is used to treat Burkitt s lymphoma and both myeloid and lymphatic leukemias. Its antiviral use is in the treatment of herpes zoster (shingles) infection (Table 43.3). It also is used to treat herpetic keratitis and viral infections resistant to idoxuridine. The drug generally is used topically, but it has been given by IV injection to individuals with serious herpesvirus infection (44). Cytarabine is deaminated rapidly in the body to an inactive compound, arabinosyluracil, which is excreted in... 

Iododeoxyuridine is a derivative of uridine used to combat herpesvirus. The viral enzyme, deoxypyrimidine kinase, readily phosphorylates 5-iododeoxyuridine and the viral DNA polymerase attempts, in turn, to incorporate them into DNA in place of the corresponding dNTP.The drug interferes with DNA replication. Uninfected cells phosphorylate 5-iododeoxyuridine only weakly, so DNA replication and virus growth are inhibited selectively in infected cells. 

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