Drugs and genetics

Use reliable resources to research and learn about an antibiotic or antiviral whose mechanism of action inhibits/effects at least one of the following:

DNA replication
DNA transcription
DNA/RNA translation
Viral replication processes
Mutation of microbial/viral DNA or RNA
The following questions should be answered when discussing your drug and may be listed by question.

Full name of the drug and its manufacturer.
The mechanism of action (MOA) of the drug. This should be a detailed answer with explanation of what the drug does to inhibit bacteria or viral pathogens. Include the following information in this explanation of the drugs MOA.
What enzyme/protein or pathway does it affect.
What is the drugs effect and how does that inhibit the pathogen growth or result in direct death
What disease or condition is the drug used for?
Are there multiple uses for the drug and what are they?
If the drug is an antibiotic, is it narrow spectrum or broad spectrum?
If it is an antiviral, does it affect host cell genetic machinery?
Does the drug pose any risks to the patient taking it and what are they. (Please DO NOT just list common side effects. Be specific about what causes those side effects)
The title of your post must include the name of the drug you are researching for easy reference by others.