6.1 Principles of antibiotic use

Question 1

what supply do antibiotics need to get to the source of action

Answer 1

blood supply (pus, dead tissue and prosthetics don’t have blood supplies)

Question 2

2 principles of rational antimicrobial use

Answer 2

1 ensure effective treatment

2 minimise collateral damage (resistance, antibiotic related illnesses, adverse effects)

Question 3

define prophylaxis

Answer 3

use of antibiotics to prevent infection of a previously uninfected site
primary= prevent initial infection
secondary= prevent recurrent episodes of infection

Question 4

what are likely sources of high temperature (5)

Answer 4

urine, wounds, chest, lines, abdomen

Question 5

define empirical treatment

Answer 5

therapy begun on the basis of a clinical “educated guess” in the absence of complete or perfect information

Question 6

factors involved in choosing antibiotic(s) (9)

Answer 6

site of infection
seriousness
likely organism
patient factors and circumstances
cost
toxicity and side effects
local/national resistance rates
other underlying diseases
contraindications

Question 7

list 3 routes and why is the route of antibiotic important

Answer 7

oral, I.V. and topical

to ensure effective drug concentrations at the site of infection

Question 8

what pharmacokinetics are important when choosing a route of antibiotics (4)

Answer 8

absorption
distribution (serum and tissue concentrations, protein binding, crossing natural boundaries)
metabolism (half life)
excretion

Question 9

define a bactericidal antibiotic and give an example

Answer 9

kills bacteria (disrupts cell wall)
penicillins, gentamicin

Question 10

define a bacteriostatic antibiotic and give an example

Answer 10

inhibits growth of bacteria (stops replication)

tetracyclines, sulphonamides

Question 11

what situations are bactericidal agents preferred (3)

Answer 11

immunocompromised
immunodeficient (HIV)
difficult cites (meningitis)

Question 12

stages of antibiotic review

Answer 12

stop if there's no evidence of infection
switch from IV to oral
change antibiotics to a narrower spectrum with results of cultures
continue and review again at 72hrs
outpatient parenteral antibiotic therapy

Question 13

when and why switch from IV to oral antibiotics

Answer 13

often within 48hrs, reduces hospital-acquired infections from lines
saves medical and nursing time
reduces discomfort for patients and enables earlier discharge
reduce chance of adverse effects

Question 14

criteria for save IV to oral switch

Answer 14

COMS
clinical improvement observed
oral route is not compromised
markers are showing a trend towards normalising
specific indication/deep seated infection

Question 15

most infections respond to ? days of treatment

Answer 15

5-7 (10 for severe)

Question 16

benefits of outpatient parenteral antimicrobial therapy

Answer 16

reduces number of hospital bed days and allows care of the patient in their own home
reduces risk of acquisition of nosocomial (hospital acquired) infections

Question 17

risks of outpatient parenteral antimicrobial therapy

Answer 17

developing acute or sub-acute and sometimes life-threatening complications (e.g. anaphylaxis, drug toxicity, line infection) or failure to resolve original infection