Antibiotics & Antivirals (5) Flashcards
What are the three types of Influenza virus?
Influenza A - Multiple host species - Highest mortality
Influenza B - Mutates less
Influenza C - Common cold like
What makes Influenza A difficult to vaccinate against?
Antigenic drift/shift it undergoes. Every year the antigens change and adapt
What ion channel allow uncoating of vesicles containing viruses?
The M2 channel
What enzyme cleaves the vesicle allowing exocytosis of viruses?
Neuraminidase
Name a M2 channel blocker
Amantadine (Strong resistance amongst viruses)
Rimantadine
What are the adverse effects of M2 channels blockers?
GI issues
Hypotension
Nephrotoxic at high doses or in patients with renal issues
What are the adverse effects of neuraminidase inhibitors?
GI issues
Headache
Nosebleeds
Name a neuraminidase inhibitor
Zanamavir (Dry powder aerosol)
Oseltamivir (Oral prodrug)
How long after onset of disease is Oseltamivir most effective?
Within 36 hours of onset of symptoms as reduces the mortality by 32%
Why are the neuraminidase inhibitors very effective amongst different strands of viruses?
Because almost all have the same neuraminidase enzyme
What is the main issue with Oseltamivir?
H1 viruses are becoming resistant to it - H1N1 is resistant to Oseltamivir but not Zanamavir
Define time dependent killing
The antibiotic is needed at the site at low concentrations for a long period of time
Define concentration dependent killing
The antibiotic is needed at the site at high concentrations for a short period of time
What are the target sites for antibiotics?
DNA synthesis
Protein synthesis
Cell wall synthesis
Name an antibiotic that targets bacterial DNA synthesis
Trimethoprim (Folic acid antagonist)
Ciprofloxacin (Quinolone)
Name an antibiotic that targets bacterial Protein synthesis
Gentamicin (Aminoglycoside)
Erythromycin (Macrolide)
Tetracyclines
Name an antibiotic that targets bacterial cell wall synthesis
Penicillins/Carbapenems/Cephalosporins (Beta lactams)
Vancomycin (Glycopeptide)
Name some ADRs of antibiotics
Hypersensitivity reactions
Fever
Nausea
Diarrhoea (As natural flora disturbed)
What are the two pathways for gaining antibiotic resistance?
Intrinsic
Extrinsic
What is Intrinsic antibiotic resistance?
The bacteria becomes resistant due to a genetic mutation
What is Extrinsic antibiotic resistance?
The bacteria becomes resistant due to acquiring it from another bacterium
What are the three types of Extrinsic antibiotic resistance?
Transformation - Uptake DNA
Conjugation - Uptake Plasmids
Transduction - Bacteriophages transfer genetic material between bacteria
