Week 10: Nucleoside Analogues, Antivirals for Hep C, and Influenza

Question 1

Nucleoside Analogues MOA

Answer 1

Acyclovir, Famciclovir, Valacyclovir

- Interfere with DNA synthesis and inhibit viral replication

Question 2

Acyclovir/Valacyclovir active against/indications

Answer 2

Valacyclovir - prodrug of acyclovir (can be taken less often)

• herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus, Epstein-Barr virus (mono), CMV, and herpes virus B
• *herpes/shingles

Question 3

Famciclovir active against / indications

Answer 3

HSV1 and HSV2, VZV, EBV, and hepatitis B virus

Question 4

Nucleoside analogues MOA

Answer 4

Acyclovir/valacyclovir - few ADRs when given PO

Famciclovir: H/A

Question 5

Nucleoside analogues cautions/CIs

Answer 5

• renal impairment - hard on kidneys - can cause crystal urea if adequate hydration is not maintained - nephrotoxicity
• OK in pregnancy
• OK in pediatrics > 2 years old

Question 6

Nucleoside analogues monitoring/pt education

Answer 6

• start drug at earliest sign of infection - Herpes zoster (shingles) - start therapy within 3 days of outbreak
• monitor for symptoms of renal failure
• monitor for mental status changes
• monitor for blood dyscrasias

Question 7

HCV treatment Ledipasvir/Sofosbuvir, Sofosbuvir/Velpatasvir

Answer 7

• always a drug combination treatment
• prescribed based on genotype and stage of dz
• I-VI genotypes (I & IV are difficult to treat; II & III are easier to treat)

Question 8

HCV treatment cautions/CIs

Answer 8

• BBW: hepatitis B virus reactivation - test patients for current or prior Hep B infection prior to starting tx
• hard on kidneys and liver - monitor for hepatic and renal issues
• drug interactions between ledipasvir/sofosbuvir and amiodarone - may cause serious bradycardia (amiodarone accumulates)

Question 9

Neuraminidase Inhibitors MOA

Answer 9

Oseltamivir (Tamiflu)-oral, Zanamivir (Relenza)-inhaled, Peramivir (Repivab)-IV

• Inhibits the neuraminidase enzyme, which prevents the release of virus and halts the spread of infection (does not kill the virus)
• effective against influenza A & B

Question 10

Neuraminidase Inhibitors ADRs

Answer 10

• neuropsychiatric evens
• severe skin reactions
• Zanamivir - bronchitis, cough, SOA (avoid if hx of respiratory dz)

Question 11

Neuraminidase Inhibitors important facts/monitoring

Answer 11

• start treatment within the first 48 hours of flu sx.

- monitor renal function (antivirals are hard on kidneys)

Question 12

Baloxavir Marboxil MOA

Answer 12

interferes with viral RNA transcription - inhibits the replication of the influenza virus

• effective against influenza A & B
• single dose - long half life - expensive