STD antivirals Flashcards
List the drugs that treat HSV (3 drugs)
Acyclovir, Famciclovir, Valacyclovir
How long do you take these drugs typically?
7-10 days
What is Famciclovir’s dosing regimen?
250mg TID
What is Acyclovir’s dosing regimen?
2 options:
- 400mg TID
- 200mg 5x per day
* *Oral bioavailability FALLS with increasing dose so you need multiple doses daily
Metabolism & elim of all HSV drugs?
Little metabolism & renal elim (dose adjust for renal dysfunction)
If a patient is allergic to one of these HSV drugs will they be allergic to the others?
YES!
What is the MOA of these drugs?
Competes with deoxyguanosine triphosphate & completely inhibits viral DNA polymerase
What must happen to these drugs in order to be activated (and thus ONLY work on cells infected with HSV)?
The HSV infected cells phosphorylate these drugs via tyrosine kinase!
**Mutation in viral thymidine kinase –> resistance to drug
AE of acyclovir?
Neurotoxicity including seizures (cuz it penetrates the CSF). Valacyclovir shares this AE**
-Also nephrolithiasis, keep patient hydrated!
Famciclovir AE?
None
How is Famciclovir metabolized?
Metabolized to Penciclovir via de-acetylation
What is the relationship between acyclovir & valacyclovir?
Valacyclovir is a prodrug that is metabolized to acyclovir. It has better oral bioavailability than acyclovir
BONUS (from micro): If HSV becomes resistant to the “cyclovirs” via mutated thymine kinase, what drug do you use?
Foscarnet
HPV prophylaxis?
Cervarix or Gardasil
Gardasil protects from?
HPV 6, 11, 16, 18 (it guards against more than Cervarix does)
