Flashcards in 12 Treatment of Viral Infections Cupo Deck (89)
In anti-viral therapy, what is the MOA of Direct Inactivation of Virus (Virucides)?
Cryotherapy or podophyllin in HPV. Destroys host/virus simultaneously. Limitation --> only for mucocutaneous lesions
What is Acyclovir (Zovirax)?
Synthetic, purine nucleoside analog
What is the spectrum of Acyclovir activity?
HSV-1, HSV-2, VZV, EBV, CMV. Potency 10 fold more potent vs HSV-1 and HSV-2 than VZV; even less active against CMV
What are the therapeutic uses of Acyclovir?
Genital Herpes Simplex I or II (5mg/kg/Q8h IV). Herpes (varicella) zoster (10mg/kg/Q8h IV). Mucocutaneous herpes relapse in immunocompromised. Disseminated or visceral HSV infection (i.e., Hepatitis, Gastritis, and Enteritis). CMV prophylaxis
What is the elimination of Acyclovir?
Renal excretion via GF and tubular secretion
What are the ADRs associated with Acyclovir?
GI (N/V/D). CNS (HA, dizziness, fatigue, altered sensorium, tremor, seizures). Skin rash. Crystalluria (risk factors: increased SCr, other toxins, dehydration)
What are the DDIs with Acyclovir?
Probenecid (increased T1/2, and acyclovir concentration). Other nephrotoxins (cyclosporine, tacrolimus)
What is Valacyclovir (Valtrex)?
Amino acid ester prodrug of Acyclovir. Developed to achieve therapeutic concentrations of Acyclovir at target sites to treat moderately susceptible strains (i.e., VZV, CMV)
What is Valacyclovirs spectrum of activity?
HSV-1, HSV-2, VZV, EBV, and CMV
What are the ADRs associated with Valacyclovir?
GI (N/V/D, constipation, abdominal pain, anorexia, dyspepsia). CNS (HA), eye pain, photophobia, tremors, dizziness. Increased LFTs
What are the DDIs with Valacyclovir?
What is Famciclovir (Famvir)?
Synthetic acyclic guanine derivative. A prodrug of Penciclovir
What is Famciclovirs spectrum of activity?
HSV-1, HSV-2, VZV, EBV
What are the ADRs associated with Famciclovir?
N/V/D, abdominal pain. HA. Fatigue. Dizziness
What are the DDIs with Famciclovir?
What is HSV-1?
More frequently associated with non-genital lesions (i.e., oral cavity, facial area)
What is HSV-2?
Usually genital lesions
What are some unique HSV properties?
Can invade and replicate in CNS. Ability to establish a latent infection
What is the Primary Infection of Genital Herpes?
HSV-2. Initial manifestation up to 3 weeks. Systemic complication: paresthesias, swelling, dysuria, inguinal adenopathy. More severe 1st episode, more likely to recur
How is Valacyclovir dosed for first genital herpes episode?
1,000mg BID x10 days
How is Valacyclovir dosed for recurrent genital herpes (episodic)?
500mg TID x3-5 days. OR. 1,000mg QD x5 days
How is Valacyclovir dosed for recurrent genital herpes (suppressive)?
500mg QD. OR. 1,000mg QD
How is Acyclovir dosed for first genital herpes episode?
400mg TID or 200mg 5x/day for 10 days
How is Acyclovir dosed for recurrent genital herpes (episodic)?
400mg TID x5 days. OR. 800mg BID x5 days. OR. 200mg 5x/day for 5 days
How is Acyclovir dosed for recurrent genital herpes (suppressive)?
How is Famciclovir dosed for first genital herpes episode?
250mg TID x10 days
How is Famciclovir dosed for recurrent genital herpes (episodic)?
125mg BID x5 days
How is Famciclovir dosed for recurrent genital herpes (suppressive)?
250mg BID up to 1 year
What is HSV Encephalitis?
Usual etiology: HSV-1. Most common, sporadic viral infection in CNS. High mortality (up to 70%) without prompt Rx