Antibiotics (1/2) Flashcards
desirable goals when designing antibiotics
- a drug with few adverse side effects and drug interactions
- specifically toxic i.e. damages a specific organism and not the patients cells and tissues
- able to achieve high conc at site of infection
- long half life
- wide range of formulations (oral tablets, IV formula, topical creams)
half life
is the time taken for the concentration of a drug within plasma to fall to a half of what its initial starting concentration was.
how is half life determined
by how quickly the drug is eliminated (clearance) from the plasma and how widely it spreads within the tissues (volume of distribution).
why is it good if antibiotic has a long half life
With antibiotics, the drug needs to stay active in the patient for as long as possible so it can work against the infection without needing repeat dosages. You can imagine this would be good for improving compliance in a patient’s treatment regime (e.g. only taking 3 tablets instead of 7) and would help in a hospital to reduce the workload of the staff having to re-administer or re-hang IV bags.
how can e classify antibiotics
- if they are lethal to bacteria or slow/ stops growth and reproduction
- if it attacks a wide variety of bacteria or specific few
- the site of action on the bacteria
- chemical structure of the antibiotics
if lethal to bacteria
bactericidal
if slows/stops growth and reproduction
bacteriostatic
attacks a wide variety
broad spectrum
attacks a specific few
narrow spectrum
name the four mechanisms of action
- inhibit cell wall synthesis
- inhibit cell membrane function
- inhibit protein synthesis
- inhibit nucleic acid synthesis
which family of antibiotics inhibit cell wall synthesis
Beta- lacta,s
Glycopeptides
which family of antibiotics inhibit protein synthesis
tetracyclines
aminoglycosides
macrolides
which family of antibiotics inhibit cell membrane function
polymixins
which family of antibiotics inhibit nucleic acid synthesis
quinolones
name the Beta-lactams
Penicillins
Cephalosporins
Carbapenems