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While I was reading about Antiviral therapy, I noticed a difference between FA and Microbiology MRS ...

In FA, it is said that Ganciclovir is monophoshorylated by HSV\VZV thymidine kinase and then bi and tri phosphorylated by the cellular kinases so that it has a preferential action against viruses since our cells don't have this thymidine Kinase ..

Now in MRS, it is said that Ganciclovir does not need the viral thymidine kinase to be monophosphorylated and can be mono, bi and triphosphorylted by the cellular enzymes

I think MRS makes more since on this since it explains why Ganciclovir is more toxic to the kidneys and the bone marrow than Acyclovir, which needs the viral Kinases for sure

So what do you guys think??

P.S. I am studying from MRS 2004 edition and FA 2008 edition
 

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While I was reading about Antiviral therapy, I noticed a difference between FA and Microbiology MRS ...

In FA, it is said that Ganciclovir is monophoshorylated by HSV\VZV thymidine kinase and then bi and tri phosphorylated by the cellular kinases so that it has a preferential action against viruses since our cells don't have this thymidine Kinase ..

Now in MRS, it is said that Ganciclovir does not need the viral thymidine kinase to be monophosphorylated and can be mono, bi and triphosphorylted by the cellular enzymes

I think MRS makes more since on this since it explains why Ganciclovir is more toxic to the kidneys and the bone marrow than Acyclovir, which needs the viral Kinases for sure

So what do you guys think??

P.S. I am studying from MRS 2004 edition and FA 2008 edition
Both Acyclovir & Ganciclovir are Guanosine analogs (nucleosides) so would require conversion to the triphosphate form to be effective.

For Ganciclovir, first phosphorylation is viral specific & requires TK in
HSV & a phosphotransferase (ul97) in CMV.


*Source. Kaplan lecture notes Pharmacology 2009.

If u still have any doubts google "UL97 mutation & Ganciclovir resistance" u well get ur answer :happy:
 
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