Antivirals acyclovir

Antivirals Acyclovir 20 mg/kg every 8 hours then 4 mg/kg every 12 hours 10 mg/kg every 8 hours... 

The first successful antiviral, acyclovir, is a nucleoside analog, and is effective against herpesvirus infections. The first antiviral drug to be approved for treating HIV, zidovudine (AZT), is also a nucleoside analog. 

RP Quinn, et al. Radioimmunoassay for desciclovir, 2-(2-amino-9H-purin-9-yl) methoxy ethanol, a prodrug for the antiviral acyclovir. J Immunoassay 8 247, 1987. 

Antiviral Acyclovir Antiviral Control of viral infections Eye ointment... 

Products have also been synthesized incorporating the known antiviral acyclovir as part of a project to synthesize third generation antiviral agents [25]. The products are of structure shown below in 17. 

Treat with systemic antivirals (acyclovir, penciclovir, and famciclovir) for 5 days. 

Several synthetic pyrimidines and purines are useful drugs Acyclovir was the first effective antiviral compound and is used to treat herpes infections 6 Mercaptopunne is one of the drugs used to treat childhood leukemia which has become a very treatable form of cancer with a cure rate approaching 80%... 

The antiviral mechanism of action of acyclovir has been reviewed (72). Acyclovir is converted to the monophosphate in herpes vims-infected cells (but only to a limited extent in uninfected cells) by viral-induced thymidine kinase. It is then further phosphorylated by host cell guanosine monophosphate (GMP) kinase to acyclovir diphosphate [66341 -17-1], which in turn is phosphorylated to the triphosphate by unidentified cellular en2ymes. Acyclovir triphosphate [66341 -18-2] inhibits HSV-1 viral DNA polymerase but not cellular DNA polymerase. As a result, acyclovir is 300 to 3000 times more toxic to herpes vimses in an HSV-infected cell than to the cell itself. Studies have shown that a once-daily dose of acyclovir is effective in prevention of recurrent HSV-2 genital herpes (1). HCMV, on the other hand, is relatively uninhibited by acyclovir. 

Unlike idoxuridiae, BVdU, and acyclovir, viral strains susceptible to ribavirin have not been found to develop a resistance to the dmg. The resistance against ribavirin is less likely because the dmg exhibits multiple sites of antiviral action. 

Novel isosteres 545 of the antiviral agent acyclovir were synthesized in three stages (84JHC697) by dehydrative coupling of 3-amino-6-aminomethyl[ 1,2,4]triazin-5-(4//)-one with 2-(benzoyloxy)ethoxyacetic acid to give the respective amide that cyclized and deprotected to give 545. It showed no activity against herpes simplex virus types I and II in cell culture (Scheme 112). 

Acyclovir (Zovirax) and penciclovir (Denavir) are the only topical antiviral dragp currently available These dragp inhibit viral replication. Acyclovir is used in the treatment of initial episodes of genital herpes, as well as heqies simplex virus infections in immunocompromised patients (patients with an immune system incapable of fighting infection). Penciclovir is used for the treatment of recurrent herpes labialis (cold sores) in adults. 

In this context, it should be noted that the specific antiviral activity of ganciclovir against HSV (which is more potent than that of acyclovir) can be fully explained by the compound being specifically recognized as substrate by the HSV-encoded TK. For CMV, however, which does not encode a virus-specified TK, the activity of ganciclovir depends on the phosphorylation by a vims-encoded protein kinase, which... 

Golankiewicz B, Ostrowski T, Goslinski T, Januszczyk P, Zeidler J, Baranowski D, De Clercq E (2001) Fluorescent tricyclic analogues of acyclovir and ganciclovir. A structure-antiviral activity study, J Med Chem 44 4284 287... 

Recently, however, there have been a number of encouraging developments in the field of antiviral therapy. For example, acycloguanosine (acyclovir see Chapter 5) has been shown to be non-toxic to host cells while specifically inhibiting the replication of herpes vimses. Successfiil clinical trials have led to the introduction of this dmg for the treatment of a variety of herpetic conditions. 

Acyclovir (acycloguanosine. Fig. 5.221) is a novel type of nucleoside analogue which becomes achvated only in herpes-infected host cells by a herpes-specific enzyme, thymidine kinase. This enzyme inihates conversion of acyclovir initially to a monophosphate and then to the antiviral triphosphate which inhibits viral DNA polymerase. The host cell polymerase is not inhibited to the same extent, and the antiviral triphosphate is not produced in uninfected cells. Ganciclovir (Fig. 5.22J) is up to 100... 

Catechins and proanthocyanidins have a documented antiviral activity. Catechins from an extract of Cocos nucifera husk fibre exhibited a strong inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-l-ACVr) [62]. The use of 10 to 20ngml of ECG and EGCG has been reported to cause 50% inhibition of human immunodeficiency virus reverse transcriptase [89], while Kara and Nakayama [90] reported that a patented chewing gum containing tea catechins is claimed to prevent viral infections against influenza and to inhibit dissemination of this virus. 

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