CP3-2 antivirals Flashcards
What are the two types of influenza virus that cause flu in humans?
Influenza A
Influenza B
What are the subtypes of influenza A?
A(H1N1)
A(H3N2)
What are the 2 lineages of influenza B?
B(Victoria)
B(Yamagata)
How are individuals with influenza treated if they are not hospitalised or in an at risk group?
No treatment
Who is classed as at risk of complicated influenza?
Those with chronic diseases affecting neurological, hepatic, renal, pulmonary or cardiac systems
Those with diabetes mellitus
Those with severe immunosuppression
Those aged over 65
Pregnant women (and up to 2 weeks post partum) especially if they have a BMI >40
What is used to treat influenza in those who need medication?
Oseltamivir (Tamiflu) - a neuraminidase inhibitor
Amantadine- a M2 proton channel blocker
What type of influenza does amantadine treat?
Type A only
Why is amantadine not used any more?
Due to high resistance to it
How effective is oseltamivir?
If given early, shortens duration of symptoms and reduces complications. Reduces death in hospitalised adults and shortens duration of hospital stay for children.
What herpes viruses have active antivirals?
HSV1 and 2
Varicella zoster virus (VZV)
Cytomegaly virus (CMV)
What antiviral are HSV1 & 2 and VSV susceptible to?
Acyclovir
Which HSV1&2 manifestations require treatment with acyclovir?
Genital or encephalitis
(Not oral or meningitis)
Which VSV manifestations require treatment with acyclovir?
Chicken pox in adults and shingles in those >60, the immunocompromised and/or if the eyes are involved
What is the mechanism of action of aciclovir?
It is a nucleoside analogue which uses the viral DNA polymerase inhibitor to terminate the chain in replication by replacing guanosine.
What mechanisms of resistance affect the action of aciclovir?
Mutations in viral thymidine kinase no longer phosphorylate aciclovir preventing the drug from working.
Mutations in DNA polymerase reduces recognition of phosphorylated aciclovir as a substrate
How does CMV manifest in the immunocompetent? Do we treat it?
Asymptomatic or mononucleosis with prolonged fever and hepatitis
No
How does CMV manifest in the immunosuppressed?
As GI disease or pneumonitis or hepatitis or nephritis or retinitis
What drugs treat CMV?
Ganciclovir (a nucleoside analogue)
Cidofovir (a monphosphate nuceloside analogue)
What treatment of CMV is most likely to be affected by drug resistance?
Ganciclovir
What drug is used to treat HIV?
AZT aka zidovudine
What is the mechanism of action of zidovudine?
Nucleoside analogue - nuceloside reverse transcriptase inhibitor terminates DNA production as used in the place of thymidine.
What is a disadvantage of only using AZT as treatment for HIV?
Using only one drug means resistance is likely to develop
What is used in conjunction with AZT to treat HIV and AIDS?
Saquinavir and ddC
What is the mechanism of action of saquinavir?
Protease inhibitor
What it the triple therapy used to treat HIV?
HAART
What is the most common treatment of HIV?
2x NRTI drugs and 1x NNRTI/PI/INI
What are the three mechanisms of actions of the drugs which can be used to treat HIV?
Protease inhibitors (prevent cleavage of protein precursors preventing production of new virons)
Non-nucleotide reverse transcriptase inhibitors (directly bind to reverse transcriptase stopping it functioning)
Integrate inhibitors (binds to inter grade preventing viral DNA inserting into the host genome)
How is dual therapy for HIV administered?
Either orally or intramuscularly
Who is treated for HIV infection?
Everyone infected irrespective of CD4 count
What is the aim of HIV treatment?
Viral suppression to prevent CD4 levels declining and progression of disease
Why are some NRTIs effective for HBV infection?
As reverse transcriptase is involved in the life cycle of HBV
What are the drugs in use for treating HBV?
Entecavir
Tenofovir D
Tenofovir alafenamide
What makes an effective antiviral?
High potency to the virus and genetic barriers to resistance.
Who is treated for HBV infection?
Those infected with developing liver fibrosis
How is it determined whether someone is at risk of developing liver fibrosis?
By ALT levels, eAg/eAb status, DNA, FibroScan estimation of liver fibrosis and age
What are the mechanism of actions of Hep C virus drugs?
Protease inhibitor
Polymerase inhibitors
Replication complex inhibitors
What non-panegenotypic drugs are used to treat HCV?
Zepatier (elbasvir and grazoprevir)
Harvoni (ledipasvir and sofosbuvir)
What pangenotypic drugs are used to treat HCV?
Maviret (gleceprevir and pibrentasvir)
Epclusa (sofosbuvir and velpatasvir)
What is the aim of HCV treatment?
To cure
How long does HCV treatment usually take?
12 weeks
Who is offered HCV treatment?
Everyone with HCV infection
