Acyclovir [Zovirax]

Question 1

What is the drug class for Acyclovir [Zovirax]?

Answer 1

Anti-Viral Agent

Question 2

What is the MOA for Acyclovir [Zovirax]?

Answer 2

Block herpes virus nucleic acid synthesis

Question 3

What are the indications for Acyclovir [Zovirax]?

Answer 3

HSV-1, HSV-2 (~1/2), VZV (~1/10), EBV (~1/10), CMV (less), HHV-6 (less); treatment and suppression

Question 4

What are the common side effects/ADRs for Acyclovir [Zovirax]?

Answer 4

N, D, headache; nephritis, tremors, delirium, seizures with overdose

Question 5

What are the contraindications for Acyclovir [Zovirax]?

Answer 5

Hypersensitivity

Question 6

What are the common drug interactions for Acyclovir [Zovirax]?

Answer 6

Probenicid, cimetadine incr conc (risk neuro & renal toxicity); acyclovir decr elim of MTX

Question 7

How should you monitor Acyclovir [Zovirax]?

Answer 7

CrCl; Response

Question 8

Additional comments regarding Acyclovir [Zovirax]?

Answer 8

PO, IV, topical formulations; requires viral kinase for activation so accumulates only in virus infected cells (40x to 100x conc as in uninfected cells); eliminated via glomerular filtration and tubular secretion; variability in viral sensitivity so varying dosing levels by virus; resistance may develop; oral availability is ~10-30% & decr w/incr dosing; PO chronic genital suppression herpes safe to ten years; genital herpes Px decr viral shedding ~90% & decr risk transmission ~50%; Valcyclovir is prodrug of acyclovir (more potent but more $)