Treatment of Viral Infections - Ch. 97 & 98 Flashcards
What are viruses?
Tiny microorganisms that infect and replicate insiede host cells
What is SARS CoV -2?
Virus = Severe acute respirotory syndrome coronavirus 2
Disease is called Coronavirus disease (COVID-19)
What are some problems associated with viral treatments?
Viruses are difficult to kill because they live inside host cells
- any drug that kills a virus may also kill cells
Viral infections are often initially asymptomatic
- delay of treatment until infection is well established (extensive replication)
What is the best response to viral infections?
Competent immune system
-Good immune system with eliminate/destroy virus replication
A healthy immune system works _______________ with the drug to eliminate or suppress viral activity
Synergistically
Who has frequent viral infections?
Immunocomprimised patients
-Cancer pt. leukemia, lymphoma
-Transplant pt. (immunosuppressants)!!!
-AIDS (attacks immune system)
How do most antiviral drugs work?
Inhibit replication of the virus inside the host cell
-Doesnβt directly destroy mature virions
What viruses are controlled by current antiviral therapy?
Cytomegalovirus (CMV)
Hepatitis virus
Herpes virus
Human immunodeficiency virus (HIV)
Influenza virus (Flu)
Respiratory syncytial virus (RSV)
What are the 2 families of antiviral medications?
Antiretroviral drugs
Antiviral drugs
What are antiretrovirals used to treat?
infections caused by HIV, the virus that causes AIDS
What are antivirals used to treat?
Infections caused by viruses
HIV is a member of which family?
Retroviruses
-Host cells turn DNA into RNA
retroviruses reverse it
HIV is a virus that leads to what syndrome?
Aquired immunodeficiency syndrome (AIDS)
How is HIV transmitted?
Sexual activity
Intravenous drug use
Mother to fetus
Whata re the 5 oppurtunist infections seen in HIV-infected patients?
Protozoal
Fungal
Viral
Bacterial
Oppurtunistic neoplasias
What are protozoal opportunistic infections?
Toxoplasmosis of the brain, others
What are fungal opportunistic infections?
Candidiasis of lungs, esophagus, trachea
Pneumocystis jirovecii pneuomonia, others
What are viral opportunistic infections?
CMV, HSV, others
What are bacterial opportunistic infections?
Various mycobacterial infections, others
Extra pulmonary tuberculosis (TB)
What are Opportunistic neoplasias?
Kaposiβs sarcoma, others
What are the 3 focused groups of antivirals for HIV (antiretrovirals)?
Reverse transcriptase inhibitors
Protease Inhibitors
Integrase inhibitors
How do Reverse transcriptase inhibitors (RTIs) work?
Block activity of the enzyme reverse transcriptase and prevents production of new DNA from viral RNA
Whata re the subclasses of RTIs?
Nucleoside RTIs (NRTIs)
Non-nuceloside RTIs (NNRTIs)
What do NRTIs do?
Competes with cell nucelosides for DNA syntehsis
Example of NRTI?
Zidovudine (AZT: Azidothymidine)
What is the major adverse effect associated with NRTIs?
Bone marrow supression
-anemia and neutropenia
How do Protease inhbitors (PIs) work?
Inhbit the retroviral protease enzyme which prevents viral protein preparation
What adverse effects are associated with PIs? (protease inhibitors)
Hyperglycemia, new/exacerbate diabetes
What are some examples of protease inhibitors?
!! Ritonavir
atazanavir sulfate
fosamprenavir
indinavir
nelfinavir
Ritonavir has many what?
Drug-drug interactions
CYP450 inhibitor and inducer
What is the full name for integrase inhibitors?
HIV integrase strand transfer inhibitors (INSTIs)
How do INSTIs work?
Inhbits insertion of HIV DNA into CD4 (T-helper) cell DNA
Examples of INSTIs?
Raltegravir
Dolutegravir
Bictegravir
Elvitegravir
What is essential for HIV treatment?
Combination therapy
What is the name of anti-viral therapy used to treat HIV?
Highly active antiretroviral therapy (HAART)
What is the goal of HAART?
Reduce HIV in plasma - viral load
= no AIDS development
= cannot pass virus to other people
What are some HIV anti-viral drug combos?
2 NRTIs + 1 NNRTI
2 NRTIs + 1 or 2 Protease inhibitors
BIKTARVY bictegravir/emtricitabine/tenofovir
alafenamide
What is BIKTARVY?
Single tab treatment of HIV-1 infection (Aug 2018)
Intergrase inhibitor + 2 NRTIs
What is taken to prevent acquisition of HIV infection by uninfected persons?
Pre-exposure Prophylaxis (PrEP) as a daily drug regime
What is Pre-exposure Prophylaxis (PrEP)?
Tenofovir and emtricitabine
2 rti combination
What is taken very soon after possible exposure to HIV?
Post-exposure Prophylaxis (PEP)
When can you start PEP?
Within 3 days
-Lasts 28 days
Example of PEP drugs?
Raltegravir + tenofovir + emtricitabine
What are the types of influenza virus?
A (~96%)
B
C
Which influenza virus has less severe symptoms?
Influenza C
What does influenza A have on the surface of its virus?
H and N surface proteins
e.g, H1N1, H3N2
What are the different kinds of Hepatitis viruses?
A, B, C, D, E, G
What viruses belong to the Herpesvirus group?
Varicella zoster virus
Herpes simplex viruses
Cytomegalovirus
What viruses are part of Varicella zoster?
Varicella = Chickenpox
Herpes Zoster = Shingles
What are the first two kinds of herpes?
HSV-1 = oral herpes
HSV-2 = genital herpes
What antivirals are used for influenza?
Neuraminidase inhibitors
How do neuraminidase inhibitors work?
Prevents realse of virus from host cell
Examples of neuraminidase inhbitor drugs?
Oseltamivir (Tamiflu)
zanamivir
Oseltamivir (Tamiflu) is active against which types of influenza?
influenza A and B virus
What adverse effects are associated with Oseltamivir (Tamiflu)?
GI disturbances
-nausea, vomiting, diarrhea
Treatment of influenza should being within what?
2 days of influenza symptom onset
When can neuraminidase inhibitors be used prophylactically?
When vaccination is not possible or in early stages of infection
Neuraminidase inhibitors were stock piled to use during what?
Swine (H1N1) flu
Neuraminidase inhibitors can reduce what when used therapeutically?
Recovery time
What is a newer flu drug?
Baloxavir
-Single dose regime
Baloxavir has equal effectiveness to which drug?
Oseltamivir
What drugs are used for Herpes virus (VZV and HSV)?
DNA polymerase inhibitors
How do DNA polymerase inhibitors work?
Act as synthetic nucleoside analogues which stops viral DNA syntehsis
Example of DNA polymerase inhbitor drug used to treat herpes virus?
Acyclovir (Zovirax)
What is Acyclovir used for?
Suppress replication of Herpes (HSV-1, HSV-2, VZV)
-For treatment of initial and recurrent episodes of these infections
What are the available forms of acyclovir?
Oral
Topical
Parenteral
What is Cytomegalovirus (CMV)?
Member of herpes virus family
Many have the virus but donβt show symptoms
How is cytomegalovirus spread?
Bodily fluids
-high risk in immunocomprimised patients
What drugs are used for cytomegalovirus (CMV)?
DNA Polymerase inhibitors
Exampels of DNA polymerase inhibitors used to treat CMV?
Ganciclovir
What can ganciclovir affect?
Brain, eye, lung and GI tract
Ganciclover is used to treat CMV ________?
CMV retinitis
-Ophthalmic form surgically implanted
What are the available forms of Ganciclovir?
Oral
Parenteral
What antiviral DNA polymerase inhibitor is used to treat respiratory syncytial virus (RSV) and hepatitis C?
Ribavirin (mechanism unclear)
How is Ribavirin administered?
PO or nasal inhalation
Which patients is Ribavirin nasal inhalation used?
Hospitalized infants with RSV