Anti-Virals Flashcards
Influenza vaccination schedule for 2 to 8 year olds
2 vaccinations spaced 1 month apart
- prime
- boost
Influenza surface proteins
H - hemagglutinin (bind epithelial cells = Infectivity)
N - neuraminidase = (virons bud off = communicability/spread)
Antigenic drift vs. Antigenic shift
Antigenic drift = yearly mutations in surface antigens requiring new vaccine and new antibodies
Ex. Covid XBB
Ex. yearly flu vaccination due to mutation of H and N
Antigenic shift = host becomes infected with two forms of the virus from different species
Ex. H1N1
Oseltamivir mechanism of action
Neuraminidase inhibitor
prevents the virus from budding off and spreading / communicability
Used for prophylaxis and treatment
List the Neuraminidase inhibitors
Oseltamivir
Zanamivir
Indications for Oseltamivir and Zanamivir
Prophylaxis
- can be taken consecutively in immunocompromised patients to bridge gap to vaccination
Treatment
- start as soon as possible, no later than 48 hours
SE Oseltamivir
Renal dose adjustment required
SE and contraindications of Zanamivir
- Do not give to people with respiratory disease (asthma, COPD, etc.)
- Can cause bronchospasm, respiratory decline, and death
Oseltamivir and Zanamivir drug interactions
Stop 48 hours before flu vaccination
If taking and vaccination given, will need to be re-vaccinated
wait 2 weeks before re-starting after the vaccination
Age for prescription of Oseltamivir
> 1 year
Safe in preganncy
Age for prescribing of Zanamivir
> 5 years of age (prophylaxis)
7 years of age (treatment)
*Inhaled, have to be able to coordinate administration
Contraindicated in respiratory diseases
Age for prescribing flu vaccination
LAIV >/= 2 years
No pregnancy
less effective as age increases
no immunocompromised patients
IIV > 6 months of age
Safe in pregnancy
Acyclovir Spectrum
Herpes Simplex Virus (HSV) > varicella zoster virus (VZV) > cytomegalovirus (CMV)
Acyclovir Mechanism of action
activated by the viral thymidine kinase (virus specific)
Converted into GTP (guanosine tri phosphate)
NUCLEOSIDE ANALOG
incorporated into the growing DNA by viral DNA polymerase
- halt DNA strand growth
- inhibit DNA polymerase
Acyclovir SE
Devoid of systemic SE
Drink a lot of water - renally cleared
Local burning and stinging
Prescription age for Acyclovir
3 months of age
Prescription age for valacyclovir
2 years
Pregnancy and acyclovir and valacyclovir
Safe in pregnancy
Should not breast feed
Prescribed in third trimester to prevent infection and transmission during delivery
Elderly and Acyclovir and Valacyclovir
Renal dose adjustment
Increased risk for renal damage and CNS effects (seizures, tremors)
Oral bioavailability of acyclovir vs. valacyclovir
30 % vs. 50%
Valacyclovir mechanism of action
Prodrug of acyclovir (NUCLEOSIDE ANALOG)
better bioavailability
Converted by liver
Thymidine kinase activates drug to form GTP
Stops DNA transcription and DNA polymerase
SE and contraindication of valacyclovir
Liver and renal inflammation (crystalizes)
Contraindicated in immunocompromised
*Higher risk of TTP
Thrombotic thrombocytopenia purpura and HUS hemolytic uremic syndrome
Drug monitoring Acyclovir / valacyclovir
CBC, WBC
- hemolytic uremic syndrome
- thrombotic thrombocytopenia purpura
LFTs
BUN, Creatinine clearance
- hepato and renal toxicity
Treatment Chickenpox children
Prevention
Vaccination
15 months and 4 years
Treatment
No anti-viral
Treatment Chickenpox adults
Anti-viral therapy within 72 hours
Ex. Valacyclovir
Treatment Shingles adults
Anti-viral therapy within 72 hours
Vaccination 1 year post infection (MI/Stroke risk if < 12 months)
65 years to 71 years
2 vaccinations 2-6 months apart
Treatment Chickenpox exposure pregnancy / neonate
Varicella immunoglobulin
pregnant adult: valacyclovir or acyclovir IV
neonate (> 2 months): can have acyclovir IV
Varicella or herpes zooster infection near eye
Medical emergency, refer to ER and opthalmology
*Retina/optic nerve/vision loss risk
