Sketchy Pharm: Acyclovir, Valacyclovir, and Famciclovir Flashcards
Acyclovir is a _____________ analog.
guanine
Think of the purine-shaped luggage with the letter G printed all over it.
What needs to happen to acyclovir before it can inhibit viral DNA polymerase?
It needs to be phosphorylated by viral thymidine kinase. This is what allows acyclovir to be selective to virally infected cells. The second and third phosphorylations are accomplished by cellular kinases.
(Think of the attendant with the Hermes attire slapping the first P sticker onto the purine luggage and the attendants in regular clothes putting the second and third stickers on.)
Which enzyme is disrupted by acyclovir?
Viral DNA polymerase
Think of the TWO lines emerging from the x-ray. The entry to it is jammed.
How are cidofovir and foscarnet active against strains of HSV, CMV, and VZV that are resistant to acyclovir?
Those guanosine analogs are already phosphorylated, and so they can bypass the thymidine-kinase step (which viruses sometimes down-regulated to gain resistance).
(Think of the baggage handler CyD pulling the CAR NET under the line –he has a Pass that allows him to get under.)
___________ work by directly inhibiting viral DNA polymerase.
Foscarnet and cidofovir
Think of CyD with the CAR NET directly turning off the x-ray machine.
What is used to treat recurrent HSV?
Valacyclovir. It has better bioavailability and is dosed daily.
(Think of the VALet parking with their DAILY rate –their goal is to help “Frequent Flyers,” which can help you remember recurrent patterns.)
(Also, the clerk is popping a candy in his mouth, representing oral availability.)
Which of the drugs discussed in this scene can be given intravenously?
Acyclovir
Think of the IVy climbing up the Hermes column. The attendant from the baggage counter also wore a Hermes helmet.
IV acyclovir is first-line treatment for ____________.
HSV encephalitis and neonatal herpes infections
What are the drugs of choice for shingles?
Valacyclovir and famciclovir
Think of the advertisements for a FAMily VALue vacations under the shingles sign.
What is the treatment window for shingles antiviral therapy?
The first three days of symptoms
Think of the 3-day FAMily VALue pack.
Acyclovir is often used prophylactically for ______________.
immunocompromised patients and pregnant women having re-activations
(Think of the “PRePare for your flight” café with the organs in the counter and the pregnant woman customer.)
What side effects can IV acyclovir cause?
Interstitial nephritis and crystaluria
Think of the kidney-shaped trash can next to the acyclovir recycling bin with the sharp objects in it.
Acyclovir, valacyclovir, foscarnet, and cidofovir can all cause _____________, especially if given in high IV doses.
CNS disturbances, like seizures, vertigo, and delirium
Think of the zombied out passenger passing through the x-ray scanner.
