Antiviral Agents Flashcards
(26 cards)
Antiviral Meds
- Limited in number of meds (harder to kill viruses)
- Hard to suppress viral replication
- viruses use host cell biochemical processed (DNA) to reproduce
- hard to suppress viral replication w/out harming the host
Acyclovir (Zovirax), Valacyclovir (Valtrex), Famiciclovir, Foscarnet
Acyclovir (Zovirax)
used for most infections caused by HERPES VIRUS groups:
- Herpes Simplex Virus (HSV) : oral (HSV1) and Genitalia (HSV2) - VERY active against - Varicella-zoster Virus (VZV) - moderately affective against - Herpes Zoster (Shingles) - Chickenpox (Varicella) - Cytomegalovirus (CMV) - strains are resistant to acyclovir
1st choice agent, topical, oral, IV
**Eliminates symptoms not the actual virus, cannot cure HSV!
Herpes Simplex Virus Type 1
Oral Herpes - Cold Sores
Transmitted through oral secretions or sores on the skin. Spread through kissing or sharing objects such as toothbrushes or eating utensils.
Can be spread even if sores aren’t present
Herpes Simplex Virus Type 2
Genital Herpes
Transmitted via intimate sexual contact.
Can be spread even if sores aren’t present
Acyclovir-Resistance
HSV develops resistance 3 ways:
- Decrease product not thymidine kinase
- Alteration of thymidine kinase so it no longer converts Acyclovir to acyclo-GMP
- Alteration of viral DNA polymerase so its less sensitive to inhibition
HSV-2 Genital Tx: Initial Infection
topical acyclovir reduces duration of viral shedding, does NOT accelerate healing
HSV-2 Genital Tx: Recurrent genital infections
topical acyclovir; not effective
Oral treatment best for both initial and Recurrent infections
HSV-2 Genital Tx: severe initial infection
IV acyclovir
HSV-2 Teaching Point
always wear a condom
HSV 2 (immunocompromised) Tx
immunocompromised patients, oral acyclovir can be used to treat primary infections of gum and mouth
severe infections in immunocompromised pts need IV acyclovir (chemo pt’s)
HSV-1 (cold sores) Tx
Oral acyclovir can be used prophylactically to prevent recurrent episodes of cold sores
Use of Valacyclovir (Valtrex)
Herpes Labilalis
Cold Sore
Aministration of IV Acyclovir
SLOWLY over 1 Hour (can have allergic rxn)
Acyclovir Adverse Effects
Phlebitis - most common Inflammation at IV site reversible Nephrotoxicity Elevated BUN and Creatinine Neurological Toxicity
Neurological Toxicity
agitation, tremors, delirium, hallucinations, myoclonus (rare)
Valacyclovir (Valtrex)
Prodrug of Acyclovir
Treats: Herpes Zoster (shingles), Herpes Simplex 2, Herpes Labialis (cold cores)
has a bigger biavailability in the body than Acyclovir (55%)
Prodrug
turns into something else in the body when given
ex: IV Valtrex turns into acyclovir in the body
Valtrex Adverse Effects
Can cause Thrombotic Thrombocytopenic Purpura and Hemolytic Uremic Syndrome in immunocompromised patient’s
Thrombotic Thrombocytopenia Purpura (TTP)
little petechea that turns into big blotches of collected blood (clotting problem)
Hemolytic Uremic Syndrome
kidneys are attacked; hemolytic breakdown of RBCs
Famiciclovir (Famvir)
Prodrug to treat Herpes Zoster and HSV-2
-Absorption from GI tract followed by enzymatic conversion to peniclovir (active form)
Benefits are equivalent to Acyclovir
-minimal adverse effects
Food decreases rate of absorption
Peniciclovir Cream (Denavair)
topical med for Cold Sores
given q2hrs x4days, except when sleeping
Modest benefits
Decreased healing time from 5 to 4.5 days
Docosanol Cream (Abreva)
topical med for Cold Sores
5x/day; OTC
Modest Benefits
Decreased healing time from 4.8 days to 4.1 days
Chicken Pox Isolation Precautions
Contact w. Airborne precautions
- until lesions are dry and crusted
- NO pregnant women to care for pt - causes teratogenic effects
