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When she woke last weekend, she just assumed the numbness in the face left side was from sleeping in the wrong position and it would go away. However during the day it continued. But she was very busy and had no time to spend on this, because so much to do, making long days at work

Sunday she woke with a sore face, tingling lips. WHAT IS IT? No clue, yet...

And then next morning at work, first meeting with colleagues and BANG an itchy spot on the lips breaks out. OUCH. HELP

The virus has spread! It was waiting until she had a low energy level, was tired. It acted fast and started to seduce the defense mechanism of the body. It started to grow and use the bodies cells and mechanism to feed and grow fast.

Her friend went to his office, came back and handed over a cream:" Just use this cream on the spots and you'll see that it will start to heal fast". And so it did.......

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What is the Herpes Simplex Virus?

Herpes Simplex virus is a very annoying virus that breaks out when your body is weakened. It sits and waits for that moment and start to grow. Blisters or skin rash occur, that can break out and release the viral load to others. The name is derived from the Greek word herpein: to creep, referring to this latent state.

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How does the medicine work?

First we have to discuss the molecules that the virus uses to feed itself and build new virus vector structures. For this purpose nucleoside structure are used. These structures are very similar to our DNA structures and are the backbones of several species. The virus builds up from molecules of , among others, guanosine.

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Figure with a Guanosine molecule and the Zovirax medicine

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Medicinal chemists discovered that if you use analogous molecular structures, you can trick the cells. For example, Zovirax (acyclovir) looks very similar: It has a guanosine part and a part of the sugar is copied in Zovirax. The body cannot really see that difference and treats it "as usual."

Lots of medicines are made via mimicking natural structures to fool the body/virus/bacteria.

Mechanism of action

The drug is converted by the bodies thymidine kinase to a monophosphate structure. Our body cannot add more phosphates fast, but the virus can! So in the last step the VIRUS converts the pro-drug to a toxic triphosphate molecule rapidly. It competitively inhibits and inactivates Herpes Simplex-specified DNA polymerases preventing further viral DNA synthesis without affecting the normal cellular processes in man. This medicine is very selective for infected cells, which increase the efficiency of the drug and minimizes resistance.

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Figure showing the work of the human kinase enzyme adding 1 phosphate group and the viral kinase enzyme adding the 2 extra causing the the DNA replication to STOP

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The other brands: Which one to buy?

Does it make a difference if you use Zovirax or if you buy Vectavir? Well, Yes it does, says the medicinal chemist.

A big difference between Zovirax and Vectavir is that the active triphosphate form of Vectavir persists within the cell for a much longer time than the activated form of Zovirax. That results in a much larger concentration of Anti viral given equivalent cellular doses(amount of cream).
And why does it stay in the cell longer? Let's have a look at its molecular structure:

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Figure showing the structural difference of Vectavir with Zovirax (see picture above)

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In Vectavir the oxygen atom in the chain has been replaced by a carbon atom, making it much less vulnerable for hydrolysis in the cell. It is far more stable!

Summary

Herpes Simplex virus can effectively been treated with anti viral creams. They work by inhibiting the DNA replication mechanism of the virus. Using more stable molecules, drug designers have made very efficient treatments for this nasty problem.

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The Steemit Medicine series give a scientific background for the mechanism of action of well known drugs in several diseases. Do you have a topic or medicine which you want to see discussed? Leave me a comment!

Previous series:
https://steemit.com/science/@beesteem/steemit-medicines-aspirin-how-it-works

https://steemit.com/science/@beesteem/coffee-and-chocolate-a-good-pair

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Bee Happy!
@beesteem