Treatment Of Viral Infections (97, 98) Flashcards
What are viruses
Tiny microorganisms that infect and replicate inside host cells
How do viruses replicate and survive
Cannot replicate on its own, and use cell machinery to synthesize protein, DNA and RNA
Virus =
Severe active respiratory syndrome coronavirus 2
(SARSC2)
Disease =
Coronavirus disease 2019
(COVID19)
Problems 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
A competent immune system has the ability to
-respond best to viral infections
-eliminates or effectively destroy virus replication
-work synergistically with the drug
Who is at risk to frequent viral infections
Immunocompromised
Examples of patients who are susceptible to viral infections
-cancer patients, leukaemia or lymphoma
-immunosuppressants
-AIDS
How do most antiviral drugs work
Inhibiting replication of virus inside host cell
-don’t directly destroy mature visions
What kind of viruses are currently able to be controlled by antiviral therapy
-cytomegalovirus
-hepatitis viruses
-herpes viruses
-human immunodeficiency virus
-influenza viruses
-respiratory syncytial virus
Antiretroviral drugs are used to treat
Infections caused by HIV
-the virus at causes AIDS
Antiviral drugs are used to treat
Infections caused by viruses
-generally every other virus other than HIV
Host cells produce ___ into ___
DNA into RNA
Retroviral cells produce __ into ___
RNA into DNA
HIV
Leads to AIDS
-retrovirus family
-sexually, IV drug use, mother to fetus
Protozoal opportunistic infections in HIV patients
Toxoplasmosis of the brain + others
Fungal opportunistic infections in HIV patients
-candidiasis of the lungs, esophagus, trachea
-pneumocystis jiroveci pneumonia, others
Viral opportunistic infections in HIV patients
CMV, HSV, others
Bacterial opportunistic infections in HIV patients
Various mycobacterial infections, extrapulmonary TB
opportunistic neoplasias infections in HIV patients
Kaposi’s sarcoma
There are four groups of antiretrovirals, what are the three we are focusing on
-reverse transcriptase inhibitors
-protease inhibitors
-integrase inhibitors
Antivirals for HIV
Reverse transcriptase inhibitors
Reverse transcriptase inhibitors
Block activity of the enzyme reverse transcriptase
-prevents production of new DNA from viral RNA
Subclasses of Reverse transcriptase inhibitors
Nucleosides RTIs and non-nucleoside RTIs
Nucleoside RTIs
Competes with cell nucleosides for DNA synthesis
-look similar to nucleoside bases and are able to join in the construction halting the furthering of DNA
Zidovudine
Nucleoside RTIs
-reverse transcriptase inhibitor
-for HIV
-milestone drug
Adverse effects of Nucleoside RTIs
Bone marrow suppression, anemia and neutropenia
Protease inhibitors
Inhibit the retroviral protease enzyme which prevents viral protein preparation
Protease is needed to chop up amino acid chains to make into proteins, inhibiting this stops protein prep
A viral enzyme means a good..
Drug target
Protease inhibitors adverse effects
Hyperglycemia to the point of new/exacerbate diabetes
Ritonavir
Protease inhibitor
-many drug to drug interactions
-CYP450 inhibitor and inducer (can make it tricky with multiple drugs)
HIV integrase strand transfer inhibitors (INSTI)
Inhibit insertion of HIV DNA into CD4 (T helper) cell DNA
-by inhibiting integrase (enzyme)
Combination therapy is essential for
HIV treatment
-antiviral resistance is increasing bc HIV has so many random mutations
HAART or Highly active antiretroviral therapy
-goal is to reduce HIV in plasma - viral load
=no aids development
=cannot pass virus to others
Drug combinations
-2 NRTIs + 1 NNRTI
-2 NRTIs + 1/2 protease inhibitors
-BIKTARVY
BIKTARVY
Single tab treatment of HIV 1 infection (inc drug adherence)
-integrase inhibitor + 2 NRTIs
PrEP or pre exposure prophylaxis
Take daily if at risk for contracting
Example- if ur partner has HIV
-Tenofovir and emtricitabine
-2 RTI combination
To prevent acquisition of HIV infection by uninflected persons..
Daily drug regime of PrEP
PEP or post exposure prophylaxis
Drugs taken very soon after possible exposure to HIV
-start within 3 days lasts 28
Example of a PEP
Raltegravir + tenofovir + emtricitabine
Most common form of influenza virus
A
~96%
Most common hepatitis
B and C
-also the only chronic conditions
Influenza virus A surface proteins
H and N
-H1N1 and H3N2
Non nucleoside RTIs
Do not reseamble a nucelotide and rather stop the enzyme from working than join the DNA synthesis
Non nucleoside RTIs
Do not reseamble a nucelotide and rather stop the enzyme from working than join the DNA synthesis
Three viruses apart of the herpesvirus group
-varicella zoster virus
-herpes simplex virus
-cytomegalovirus
Varicella zoster virus includes
-chickenpox (varicella)
-shingles (herpes zoster)
Herpes simplex viruses includes
-HSV 1 (oral herpes)
-HSV 2 (genital herpes)
Neuraminidase inhibtors
Prevent release of virus from host cell
-treat influenza virus
-treatment begins within 2 days of symptoms
Example of neuraminidase inhibtiors
Oseltamivir
Oseltamivir
Neuraminidase inhibitor
-active against influenza A and B virus
-adverse effects= nausea and vomiting
Neuraminidase inhibtors can be used
Prophylactically when vaccination is not possible or in early stages of infection
-usually stock piled to use in swine flu
Neuraminidase inhibtiors can reduce recovery time when used
Therapeutically
Baloxavir (DO NOT STUDY)
Newer flu drug
-single dose regime
-equal effectiveness to oseltamivir
DNA polymerase inhibtors
Synthetic nucleoside analogues
-stops viral DNA synthesis
Example of DNA polymerase inhibtiors
Acyclovir
Acyclovir
Used to suppress replication of herpes virus
-good for initial and recurrent episodes
-oral, topical, parenteral forms
Cytomegalovirus
Member of herpesvirus family
-asymptomatic (risky in immunocompromised patients)
-spread by bodily fluids
Ganciclovir
DNA polymerase inhibitor
-synthetic nucleoside analogue
Ganciclovir
DNA polymerase inhibitor
-synthetic nucleoside analogue
Ganciclovir is used to treat
-Cytomegalovirus (which affects brain, eye, lung, GI)
-CMV retinitis (ophthalmic eyes)
Ganciclovir is available in
Oral and parenteral forms
Ribavirin
Synthetic nucleoside
-mechanisms are unclear
Ribavirin is used to treat
-respiratory syncytial virus
-hep C
Ribavirin is taken
Via nasal inhalation
-hospitalized infants with RSV
