Antivirals 1 Flashcards
Why do drugs that block viral replication have limited effectiveness?
Because symptoms may appear late in the disease. AKA most viral particles have already been replicated. So drug won’t do much.
What is neurimidase?
A viral enzyme essential to the life cycle of the virus.
How do oseltamivir and zanamivir work?
Prevent the release of new visions.
Selective against type A and B
Do not interfere with the immune response to the influenza vaccine (will still build up a response)
Prevents infection prophylactically
Decreases intensity and duration of symptoms when given shortly after onset.
How are oseltamivir and zanamivir administers?
Oseltamivir: Oral
Zanamivir: Nasal.
They work exactly the same, but diff names for diff admins.
Side effects of oseltamivir?
GI problems.
Pro drug activated by liver.
Not much metabolism.
Side effects of zanamivir?
Bronchospasm.
Avoid in pts with asthma or COPD.
Spectrum of neurimidase inhibitors?
Influenza A and B
Spectrum of viral uncoating inhibitors?
Only influenza A. Effective for Tx and prevention. Does not impair body from building an immune response with vaccine.
Amantadine and rimantidine Spectrum Pharmacokinetics Adverse effects Resistance
- Only influenza A
- well absorbed orally
- GI, caution in pregnant people e
- Develops rapidly. Cross resistance between the two drugs, so now infrequently used.
Amantadine and rimantidine
Which one penetrates CNS?
Which one is extensively metabolized?
Amantidine.
Rimantidine is extensively processed by liver. Amantadine appears unchanged in urine.
Amantidine side effect
Penetrates CNS. May accumulate to toxic levels in pts with renal failure. Unchanged in urine.
Hepatitis types and what does an infection cause?
A, B, C, D, E. B and C are the most common, blood borne.
Replicate in and cause destruction of hepatocytes.
Interferon A
- MOA?
- Pharmacokinetics
- Adverse effects
- Mainly used for which hepatitis
- unknown
- Not active orally. Subcutaneous delivery common.
- Flu-like symptoms. Fatigue, mental depression. IFN retinopathy.
- Mainly use for B and C
IFN retinopathy
Presents as CWS and hemorrhages around the ON in the posterior pole.
3-5 months after tx.
Monitor pts on interferon therapy every 6 months.
Will improve if meds stop
5A inhibitors MOA
Interfere with RNA replication