Antivirals Flashcards
Viruses
- Tiny microorganisms that infect and replicate inside host cells
- Coronavirus - SARS CoV-2
How do Viruses work
- use host cell machinery to synthesize protein, DNA, and RNA
- Viruses can’t replicate on own
- Must attach/enter a host cell
Problems of viral treatments
- Infections live in host cells- to kill virus may also kill cells
- Initially asymptomatic- delay treatment until virus is well established
Host defense in a competent immune system
- best response to viral infections
- Well functioning immune system will eliminate or effectively destroy virus replication
- Healthy immune system works with the drug to eliminate or suppress viral activity
Host Defense in Immunocompromised
Have frequent viral infections especially
1. cancer pts
2. Transplant pts
3. AIDs pts disease attacks their immune system
Antiviral medications
Do what
- work by inhibiting replication of virus in host
- don’t directly destroy mature virions
Viruses controlled by current antiviral therapy
- Cytomegalovirus (CMV)
- Hep virus
- Herpes virus
- HIV
- Influenza virus (flu)
- Respiratory syncytial virus (RSV)
Antiretroviral Drugs
treat HIV infections virus causing AIDs
HIV host cells
DNA becomes RNA
HIV retroviral
RNA becomes DNA
HIV
-Leads to AIDs
-Retrovirus family
-Transmitted sexually, iv drugs(blood), mom to fetus
Opportunistic Infections in HIV pts
- Protozoal
- Fungal
- Viral
Opportunistic infections in HIV: Protozoal
Toxoplasmosis of the brain
Opportunistic infections in HIV: Fungal
-Candidiasis of lungs, esophagus, trachea
-Pneumocystis jirovecii pneumonia
Opportunistic infections in HIV: Opportunistic infections in HIV: Viral
-CMV
-HSV
-others
Opportunistic infections in HIV: Bacterial
-Various mycobacterial infections
-Extrapulmonary tuberculosis (TB)
Opportunistic Neoplasms in HIV:
Kaposi’s Sarcoma
Antivirals for HIV
-Reverse transcriptase inhibitors
-Protease Inhibitors
-Integrase Inhibitors
Reverse transcriptase inhibitors (RTIs)
Block activity of enzyme reverse transcriptase
-prevent production on new DNA from viral RNA
Reverse Transcriptase inhibitors: subclasses
-Nucleoside RTIs
-Non-nucleoside RTIs
Nucleoside RTIs
Competes with cell nucleosides for DNA synthesis
-Zidovudine (AZT: azidothymidine)
Zidovudine (AZT: azidothymidine): Adverse effects
Bone Marrow suppression
-anemia and neutropenia
Protease Inhibitors
Inhibit the retroviral protease enzyme, preventing viral protein preparation
What is a good target for antiviral drugs
viral enzymes
Protease inhibitor adverse effects
-Hyperglycemia
-Cause new or exacerbate diseases
Protease Inhibitor- Ritonavir
has many drug-drug interactions
-CYP450 inhibitor and inducer
Other Protease Inhibitor drugs
-atazanavir
-fosamprenavir
-indinavir
-nelifnavir
Integrase Inhibitors
HIV integrase Strand Transfer Inhibitors (INSTIs)
HIV integrase Strand Transfer Inhibitors (INSTIs)
Inhibit insertion of HIV DNA into CD4 (T-helper) cell DNA
Other Integrase inhibitors
-raltegravir
-dolutegravir
-bitegravir
-elvitegravir
What type of therapy is used for HIV treatment
Combination therapy is essential
Highly Active AntiRetroviral Therapy (HAART)
Goal is to reduce HIV in plasma - Viral load
-No AIDs development
-cannot pass virus to others
Drug combinations
- 2 NRTIs + 1NNRTI
- 2 NRTIs + 1 or 2 Protease inhibitors
- BIKTARVY (bictegravir/emtricitabine/tenofovir/alafenmide)
BIKTARVY (bictegravir/emtricitabine/tenofovir/alafenmide)
-Single tab treatment of HIV-1 infection (2018)
-Integrase inhibitor + 2 NRTIs
Pre-Exposure Prophylaxis (PrEP)
Tenofivir and emtricitabine
-2 RTI combination
Daily drug regime for HIV is to
To prevent acquisition of HIV infection by uninfected persons
Post-Exposure Prophylaxis (PEP)
-Drugs taken very soon after possible exposure to HIV
-start within 3 days and lasts 28
-Eg. Raltegravir + tenofovir + emtricitabine
Influenza
Has many different strains
-A is 96%
-B
-C is less severe symptoms
What causes the differentiation in influenza
H + N surface proteins
-eg. H1N1 vs. H3N2
Herpes virus group
-Varicella Zoster virus
-Herpes simplex virus
Cytomegalovirus
Varicella virus types
-Chicken Pox (Varicella)
-Shingles (Herpes zoster)
Herpes simplex virus types
-HSV-1 (Oral)
-HSV-2 (Genital)
Drugs for influeza
-Oseltamivir (Tamiflu)
-Zanamivir
-Baloxavir
Influenza treatment
-Should begin within 2 days of symptom onset
-Can be used prophylactically if vaccine isn’t an option
-Can reduce recovery time when used therapeutically
Baloxavir treatment (Influenza)
-Newer drug
-single dose regime
- Equally effective as oseltamivir
Drugs for herpes virus
-Synthetic nucleoside analogues
-Acyclovir (Zovirax)
Synthetic nucleoside analogues
-treats herpes virus
-Nucleosides are DNA building blocks
-Stops viral DNA synthesis
Acyclovir (Zovirax)
-Used to suppress replication of herpes virus
-Used for initial and recurrent episodes
-Topical, oral, parenteral forms
What forms of herpes does Acyclvir suppress
-HSV-1
-HSV-2
-VSV
Drugs for herpes Cytomegalovirus
DNA Polymerase Inhibitors
-Ganciclovir
Cytomegalovirus
-Herpes virus family
-May have virus but no symptoms
-spread by bodily fluids
-can affect brain, eyes, lungs, and GI
Ganciclovir treats
-Cytomegalovirus
-CMV retinitis (Ophthalmic form is surgically implanted)
-available in parenteral forms
Ribavirin
-synthetic nucleoside
-PO or inhalation
-Treats- Respiratory syncytial virus (RSV), Hep C
