Influenza

What are three properties of viruses?

1. escape from immune surveillance

2. persistent of latent reservoirs

3. Drug resistance

What are some causes of drug resistance?

prevention of penetration of the drug to its target site, enzymatic destruction or inactivation o f a drug, cellular or metabolic changes at target site(s), and rapid efflux (pumping of drug out of cell) greater exit

What is hereditary drug resistance?

resistance (R) factor; intrinsic drug resistance that is passed on

How can viral resistance be mnimized?

by the discriminate use of drugs in appropriate concentrations and dosages

Who was considered a high risk group for H1N1 influenza?

children under 2, adults 65 years and older, and pregnant women

What are secondary complications of seasonal influenza?

bronchitis, sinusitis, otitis media, pneumonia, rhinitis

Which viral infection (flu vs cold) has a prominent headache?

flu

Which viral infection (flu vs cold) has a high fever for 3-4 days?

flu

Which viral infection (flu vs cold) has a hacking cough?

cold

Which viral infection (flu vs cold) has a gradual onset?

cold

Which viral infection (flu vs cold) has myalgia?

flu

When should you take a rapid influenza test?

3-4 days after symptom onset (but 48 hours according to dr. cha)

What is a RIDT?

rapid influenza diagnostic test

When is molecular testing recommended?

hospitalized patients (maybe also symptomatic with negative test)

What do M2 inhibitors block?

uncoating

What do VP inhibitors block?

transcription

What do NA inhibitors block?

release

What class of medications is zanamavir?

NA inhibitor

What is the brand name of zanamivir?

Relenza

What is the indication of zanamavir?

influenza A and B

What is the minimum age for zanamivir prophylaxis treatment?

5 years old

What is the minimum age for treatment using zanamavir?

7 years old

True or False: a positive rapid (or non rapid) test is needed in order to take zanamavir?

true

What is the route of administration for zanamivir?

intranasal or inhaled

True or false: zanamivir has good oral bioavailability?

false

How long is the recommended therapy with zanamivir?

5 days

How soon should you initiate therapy with zanamivir?

with 48 hours of developing symptoms

What are some ADRs of zanamivir?

pretty well tolerated; headache, diarrhea, nausea, bronchitis, cough

What patients should use zanamivir cautiously?

patients with underlying asthma or COPD due to respiratory side effects

What is the indication of oseltamavir?

type A and B influenza treatment or prophylaxis

What is the minimum age for oseltamavir?

1 year old

True or false: food alters the bioavailability of oseltamivir?

false

What are the adverse effects of oseltamavir?

NVD, abdominal pain, headache, dizziness, cough, insomnia, vertigo

What is postexposure influenza prophylaxis?

prophylaxis after exposure to influenza-infected individuals in household, workplace, social settings or community

What is seasonal influenza prophylaxis?

during community outbreak; prophylaxis for entire influenza vaccine

What is postvaccination influenza prophylaxis?

prophylaxis for 2-4 weeks after receving influenza vaccine

What is outbreak control influenza prophylaxis?

prophylaxis in institutional settings after influenza confirmed as present

What is the common dose of oseltamivir?

75 mg (12.5 mL) PO BID

True or false: oseltamivir needs to be adjusted for renal function.

true

What DDI does oseltamivir have?

probenecid will increase active metabolite x 2

What is the indication for peramivir?

salvage or serious influenza infection; when symptoms have lasted over 2 days

What is the minimum age for peramivir?

6 months old

What is the route of administration of peramivir?

IV only

What is the adult dose of peramivir?

600 mg infused over 15-30 mins

What are some ADRs of peramavir?

CNS, diarrhea, constipation, dysphagia, hypersensitivity

True or False: most influenza medications limit vaccine effectiveness

true

What class of medication is amantadine?

M2 inhibitor

What is the indication for amantadine and rimantiadine?

type A influenza ONLY; no activity against type B

When does amantadine or rimantadine need to be administered?

within 48 hours to reduce severity and shorten duration or illness

Which M2 inhibitor can be given to both children and adults?

amantadine

What are the ADRs of amantadine and rimantadine?

insomnia and dizziness

True or False: M2 inhibitors should be avoided due to increasing resistance

true

What is the MOA of baloxavir?

inhibits cap-dependent endonuclease (viral RNA polymerase)

What is the indication for baloxavir?

treatment ion 5–12-year-olds without chronic conditions, at least 12 years old

prophylaxis in at least 5 years old

What is the dose for baloxavir?

80 mg PO QD

What are the ADRs for baloxavir?

hypersensitivity

What drug interaction occurs with baloxavir?

magnesium (and other metal chelators), interacts with efficacy of vaccine

What are the priority groups for antiviral prophylaxis during an influenza season?

hospitalized for influenza, health care workers and EMS and other response providers with direct patient contact, highest risk outpatients (immunocompromised, pregnant), moderate-risk outpatients (children 12-23 months, people over 65, and people with underlying health conditions)

What is the best machanism for prevention of influenza?

vaccination