Anti-Bacterials

Question 1

Bactericidal vs Bacteriostatic

Answer 1

Bactericidal kills bacteria

Bacteriostatic slows bacterial proliferation, less effective in immunocompromised

Question 2

Gram + bacteria susceptibility

Answer 2

cell wall synthesis interfered with well by beta-lactams

Question 3

Gram - susceptibility

Answer 3

Cell wall impermeant and beta-lactamase enzymes prevent cell wall interference

Question 4

Mycobacteria beta lactam susceptibility

Answer 4

Different cell wall composition so beta-lactams don’t work

Question 5

Drug classes affecting cell wall

Answer 5

Beta-lactams (penicillins/cephalosporins)
Vancomycin
Polymyxins
Anti-mycobacterials

Question 6

beta-lactam MOA

Answer 6

Prevents transpeptidation and decarboxylation in formation of proteoglycan cell wall

Question 7

penicillins used in what situations

Answer 7

benzylpenicillin (IV), phenoxymethylpenicillin (oral) for narrow spectrum non-resistance gram + infection

Question 8

beta-lactamase resistant drugs

Answer 8

Methicillin (IV), flucloxacillin (oral) for beta-lactamase producing organisms

Question 9

Broad-spec penicillins

Answer 9

Amoxicillin/ampicillin (oral) more hydrophilic so can enter some gram - bacteria, beta-lactamase producing bacteria resistant to these so given with clavulinic acid which inhibits the enzyme

Question 10

Pseudomonas drugs

Answer 10

Ticarcillin/piperacillin (IV)

Question 11

Penicillin SE

Answer 11

Hypersensitivity when metabolised

GI disturbance/infection due to destruction of gut flora

Question 12

Vancomycin MOA

Answer 12

Prevents transglycosylation in cell wall synthesis by binding to precursors

Question 13

Vancomycin uses (all IV)

Answer 13

beta-lactam sensitive people
MRSA
C. difficile bowel superinfection

Question 14

Polymyxin uses

Answer 14

Topical application to ear/eye/skin or for gut sterilisation pre-surgery, not used much as very toxic

Question 15

Anti-mycobacterials

Answer 15

Isoniazid (bacteriostatic unless rapidly dividing mycobacterium)
Ethambutol

Question 16

Isoniazid MOA

Answer 16

Inhibits mycolic acid synth

Question 17

Ethambutol MOA

Answer 17

Inhibits mycolic acid incorporation in cell wall

Question 18

Ethambutol uses

Answer 18

Combination with isoniazid, useful for isoniazid resistant

Question 19

Cephalosporin 3 generations of drugs and uses

Answer 19

1st - cephardroxil (oral, for resistant UTIs)
2nd - cefuroxime (IV/oral, when other antibios ineffective)
3rd - Ceftazidime (Oral for gram - (2nd gen for +), ceftriaxone has longer half life)

Question 20

Sulphonamides MOA

Answer 20

sulfamethoxazole inhibit folate synthesis step in DNA synth, bacteriostatic

Question 21

Trimethoprim MOA

Answer 21

Inhibits tetrahydrofolate from dirhydrofolate in DNA synth, bacteriostatic

Question 22

Folic acid synth inhibitor uses

Answer 22

Co-trimoxazole (sulfamethoxazole + trimethoprim mix) used mainly to treat P. jiroveci pneumonia and toxoplasmosis, lots of resistance though
Don’t affect humans as all of our folate is dietary not synthesised

Question 23

Sulphonamide SE

Answer 23

Allergic reactions

Aplastic/haemolytic anaemia in rare cases

Question 24

Sulphones use

Answer 24

Dapsone similar to sulphonamides but also affect mycobacteria and used in leprosy

Question 25

Quinolone MOA

Answer 25

Ciprofloxacin inhibits DNA gyrase to prevent bacterial DNA supercoiling

Question 26

Quinolone uses

Answer 26

Broad spec and bactericidal so used against gram - and resistant strains (but resistance developing due to use in farming

Question 27

Quinolone SE

Answer 27

Nausea vomiting etc | Rarely convulsions as it's a GABA antagonist

Question 28

Rifampicin MOA

Answer 28

Prokaryotic RNA polymerase inhibitor, bacteriostatic

Question 29

Rifampicin use

Answer 29

In combination TB therapy, broad spec

Question 30

Rifampicin SE

Answer 30

Orange secretions

Question 31

5-nitroimidazole MOA

Answer 31

Metronidazole produces metabolites that interfere with DNA and it's synth

Question 32

5-nitroimidazole SE

Answer 32

GI disturbance

Question 33

5-nitroimidazole use

Answer 33

Used against certain protozoa and selective for anaerobes (e.g. H. pylori)

Question 34

Bacterial protein synth inhibitor classes

Answer 34

Tetracyclines Aminoglycosides Chloramphenicol Macrolides

Question 35

Tetracycline MOA

Answer 35

Doxycycline, tetracycline, tigecycline prevent aa binding to tRNA at A site, bacteriostatic

Question 36

Tetracycline SE

Answer 36

Reduced effectiveness with metal ions e.g. milk Ca++ Avoided in kids/pregnant women as binds to Ca++ Diarrhoa/nausea

Question 37

Aminoglycoside MOA

Answer 37

Streptomycin/gentamycin prevents codon/anti-codon recognition when given IV

Question 38

Aminoglycoside use

Answer 38

Not used much as very hydrophilic and toxic to host at active conc Sometimes with beta-lactam Last resort if lots of resistance

Question 39

Chloramphenicol MOA

Answer 39

Prevents transpeptidation during translation, bacteriostatic

Question 40

Chloramphenicol use

Answer 40

Well absorbed in CNS so used in meningitis | Broad spec, used in life threatening infections where there's resistance

Question 41

Macrolides MOA

Answer 41

Erythromycin, clarithromycin block translocation in bacterial protein synth

Question 42

Macrolides use

Answer 42

Treat gram + bacteria in penicillin resistant patients | Used in mycoplasmas and legionella

Question 43

Macrolides SE

Answer 43

Inhibits P450 so not to be taken with warfarin, can causes cholestatic hepatitis