M15 - antibiotics

Question 1

define antibiotics

Answer 1

a drug used to treat or prevent infection caused by micro-organisms

Question 2

define bacteriostatic

Answer 2

inhibit the growth of bacteria

Question 3

define bacteriocidal

Answer 3

kills bacteria

Question 4

are antibiotics considered a subsititute for a functional immune system?

Answer 4

no

Question 5

list some features of an ideal antibiotic

Answer 5

Selective toxicity/minimal toxicity to host
long half life
no adverse drug interactions/side effects

Question 6

list some antibiotic targets

Answer 6

• cell wall
• ribosomes
• dna replication

Question 7

cell wall protects cell from internal osmotic pressure, what is it targeted by?

Answer 7

B-lactam (penicillins) and glycopeptide antibiotics

Question 8

what is the bacteria cell wall made up of?

Answer 8

repeated sugar units cross linked by peptide side chains

Question 9

which antibiotic causes suicide of the cell?

Answer 9

penicillin

Question 10

amoxycillin has a wide spectrum and a wide tissue distribution, what % binds to plasma proteins?

Answer 10

20

Question 11

what is special about co-amoxiclav?

Answer 11

inhibits beta-lactamases and provides better pain relief 2-3 days after

Question 12

what is co-amoxiclav not suitable for

Answer 12

empiric prescribing

Question 13

for empiric prescribing, is penicillin better than amoxycillin

Answer 13

penicillin

Question 14

list three advantages of penicillin (beta-lactam antibiotcics)

Answer 14

safe
narrow to wide spectrum
variety

Question 15

list three disadvantages of penecillin

Answer 15

resistance
rapidly excreted
hypersensitivity

Question 16

how do glycopeptides inhibit peptidoglycan synthesis?

Answer 16

binds to end of peptide side chains and prevents its incorporation into the cell wall

Question 17

what does protein synthesiis involve?

Answer 17

ribosomes moving along mRNA molecules that have been transcribed from DNA

Question 18

what is side effect of glycopeptides?

Answer 18

can cause renal toxicity

Question 19

list a couple of antibiotics targeting protein synthesis

Answer 19

tetracyclines –> deoxycyline
macrolides –> erythromycin
lincosamides –> clindamycin

Question 20

what is toxic regarding aminoglycosides? (gentamicin)

Answer 20

causes damage to kidneys and VIII cranial nerve (deafness and dizziness), so need to monitor blood levels of aminoglycosides

Question 21

what is the mode of action of tetracyclines?

Answer 21

actively transported into cell

Question 22

what is the adverse effect of tetracycline?

Answer 22

destruction of normal intestinal flora resulting in increased secondary infections;staining and impairment of the structure of bone and teeth

Question 23

what is the mode of action of lincosamides?

Answer 23

prevents peptide bond synthesis

Question 24

where is lincosamides (clindamycin) found and used?

Answer 24

high concentration in bones, used for abscesses of bone or soft tissue or joint replacement

Question 25

which antibiotics are associated with the macrolides?

Answer 25

erythromycin
clarythromycin
azithromycin

Question 26

which antibiotics inhibit nucleic synthesis?

Answer 26

metronidazol; anaerobes and protozoa

Question 27

metronidazole

Answer 27

28% of all primary care dental prescriptions

activity against anaerobes and some parasites

Question 28

ciprofloxacin (IV & oral) and levofloxacin (IV) (bacteriocidal)

Answer 28

they are a part of fluoroquinolones and the use of these broad spectrum antibiotics is now severely restricted in tayside in an attempt to reduce the risk of clostrum difficile gut infection, especially in elderly patients

Question 29

side effect of antibiotics

Answer 29

metronidazole - interacts with alcohol
gentamicin - renal and VIII damage
nausea, vomiting, diarrhoea

Question 30

what are the antibodies we try to avoid using?

Answer 30

the 4 Cs antibiotics 
- cephalosporins 
- co-ampxiclav *
-ciprofloxacin 
- clindamycin
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