anti-viral drugs

Question 1

Stopping a Virus

Answer 1

Host Defence Mechanisms
Humoral
Cell mediated
Antiviral Agents
Inhibition of nucleic acid synthesis
Inhibition of viral proteins this is why they work better in early stages

Question 2

immune-stimulation with vaccine

Answer 2

Administration of human immune globulin

Administration of immuno-stimulant drugs

Question 3

anti herpetic agents

Answer 3

Aciclovir – An analogue of the purine nucleoside guanosine. These things get incorporated into dna and can induce toxicicty if used wrongTransformed by phosphorylation into active state by viral enzymes- the virus helps here
Greater affinity for viral than host enzymes therefore less toxic- limitation on dose used as it can beome toxic if goes into human dna
Incorporates into viral DNA
Inhibits viral DNA synthesis- early stages where most replicaton occurs

Question 4

pharmacokinetics of acycloviraciclovir

Answer 4

Aciclovir half-life is 2.5 hours
Crosses the blood-brain barrier- can get into the cranium and cause a viral enchaph
Excreted in the kidneys
Resistance is rare
Administration: May be prescribed topically or intravenously

Question 5

unwanted acyclovir effects

Answer 5

Nausea and headaches

Transient burning sensation on application good idea to tell a patient this or they may give up with it.

Question 6

idoxuridine

Answer 6

A thymidine analogue
Phosphorylated in cells and is incorporated into cellular and viral DNA
Unlike aciclovir it does not block DNA synthesis
Mainly used against DNA viruses and is too toxic for systemic use
Topically only!!!!!

Question 7

hiv anti-viral

Answer 7

Zidovudine (AZT)

Question 8

Zidovudine (AZT)

mode of action

Answer 8

A thymidine analogue
Cytopathic against HIV-1
Inhibits viral RNA-dependent DNA polymerase
Prevents further nucleotides from being incorporated into a growing strand of DNA
Action can be enhanced by aciclovir and interferon- synergistic effect
Administration: Orally or by continuous intravenous infusion- cannot be quick needs a drip

Question 9

pharmacokinetics of ATZ

Answer 9

Rapidly absorbed from GIT- good because it is given orally
Peak plasma concentration after 30-90 minutes
Metabolised in the liver and excreted via kidneys

Question 10

ATZ UNWANTED EFFECTS

Answer 10

Anaemia
Granulocytopaenia- not many granulocytes (white blood cells)

Regular blood count every 2 weeks

Question 11

Reverse transcriptase inhibitors

Answer 11

An RNA-dependent DNA polymerase inhibitor

They are nucleoside analogues – some of the newer drugs e.g. nevirapine are non-nucleosides

Question 12

non-nucleoside analogues

Answer 12

Used in the treatment of AIDS

Example: Nevirapine and Delavirdine

Question 13

interferon

Answer 13

Interferons – a group of cytokines drugs-naturally occuring
3 main types: Alpha/Beta/Gamma
Can be used with MS
Glycoproteins produced by the body in response to a viral infection
Enhance the cytotoxic capacity of T-lymphocytes

Question 14

prions

Answer 14

proteins that case configuration changes in protein
autoclave
cod- blood infusion or growth hormone steroids
expensive