PHARM Influenza (Staudinger) Flashcards
What are the 3 neuraminidase inhibitors used as anti-influenza drugs and which can be given orally, via IV, and inhalation?
- Oseltamivir = oral
- Zanamivir = inhaled/inZpired
- Peramivir = IV
Which anti-influenza class has activity against both influenza A and B?
Neuraminidase inhibitors
What is the MOA of the neuraminidase inhibitors as anti-influenza drugs?
Interfere with the release (and activation) of influenza A and B progeny from infected host cells
What specifically is cleaved by neuroaminidase enzymes?
Neuroaminidase noramlly cleaves sialic acid from glycoproteins found on the cell surface of virions to promote continued viral replication.
NAIs impair the sepration of sialic acid, which renders the virions ineffective, resulting in halted viral spread.
Oseltamivir can interfere with flu vaccine effectivess. How can this be avoided?
Wait two weeks before
or 48hrs after
However, oseltamivir does NOT interact with CYP or UDPGT
What is the indication of oseltamivir?
Uncomplicated acute illness d/2 Influenza A and B
Prophylaxis is best if started within 48hrs of symptom onset
For 1yo +
3 common AE’s of olseltamivir; what may be done to decrease them?
- HA, nausea, and vomiting
- Take w/ food to decrease N/V
Doses of oseltamivir need to be adjusted in pt’s with what underlying problem?
Renal insufficiency
Which anti-influenza class of drugs can be given as once-daily prophylaxis?
Neuraminidase inhibitors (oseltamivir and/or zanamivir)
What are the 2 common AE’s of oseltamivir associated with prophylactic use?
Fatigue and diarrhea
What is the indication for zanamivir?
Acute uncomplicated Influenza A or B
Prophylaxis if started within 48hrs of sx onset
12yo +
After inhalation of zanamivir, where does 80-90% of it deposit?
Concentrated in lungs and oropharynx (aborbed, and excreted in urine)
Bioavailabilty is ~2%
Major AE’s associated with zanamivir; should not be administered with what underlying issue?
Cough
Bronchospam (ocassionally severe)*** –> don’t give to pt w/ underlying airway disease!
Reversible ↓ in pulmonary function
What are the contraindications of zanamivir?
Lactose intolerance
CNS dysfnx
Mental illness
Seizures (Watch this!)
Vaccine planned in next 2 weeks, or received in past 48hrs
What is the matabolism of zanamivir?
100% eliminated by the kidneys without any metabolic biotransformation
When should tx with neuraminidase inhibitors be given to be most effective against influenza?
Within 48 hours
What pt population peramivir is recommended for?
18yo +
What is the main potential AE of peramivir, and which rare AE has been seen?
Main = diarrhea
Hypersensitivity rxns –> Steven-Johnsons syndrome, Erythema multiforme have rarely been seen
↑ risk for delirium, hallucinations, and abnormal behavior
What is the MOA of baloxavir?
Polymerase acidic endonuclease inhibitor
Indicated for acute uncomplicated flu for pts 12yo + starting within 48hrs of sx onset
What are the 2 adamantanes used as anti-influenza drugs?
- Amantadine
- Rimantadine
Indication for amantadine
Prophylaxis and tx of sign and sx of Influenza A
CONTRAINDICATED: hypersensitivy to amantadine
What is the MOA of the adamantanes; amantadine and rimantadine used as anti-influenza drugs?
who knows???
Thought to block M2 proton ion channels, and therefore inhibit entry/uncoating of the viral RNA
May also inhbit reassembly WITHIN infected cells, preventing replication
No interaction with flu vaccne
Which adamantane is excreted unchanged in the urine and which undergoes extensive metabolism?
amantadine is excreted unchanged ***
rimantadine undergoes extensive metbolism
*** Fx impairment of the kideneys can increase clearance form 10-14 hr half-life to 7-10 day.
Why are the adamantanes no longer recommended for prevention or treatment of influenza?
High rates of resistance in both H1N1 and H3N2 viruses
Which anti-influenza class are both teratogenic and embryotoxic?
Adamantanes
2 most common AE’s of the adamantanes?
GI (nausea and anorexia)
CNS –> nervousness, difficulty in concentrating, insomnia, light-headedness
What is a more serious AE associated with the adamantanes; more frequent with which drug in the class?
- Marked behavioral changes + Delirium + Hallucinations
- Agitation + Seizures
- More frequent w/ amantadine
