ST4 - Antibiotics

Question 1

What is the broad spectrum penicillin?

Answer 1

Co-amoxiclav

Question 2

What is the broad spectrum cephalosporin?

Answer 2

Cefuroxime

Question 3

How should penicillin G and V be administered?

Answer 3

G - IV V - Oral

Question 4

Are beta-lactams safe in pregnancy?

Answer 4

Yes

Question 5

In which patients are aminoglycosides (eg. gentamicin) at risk of causing toxicity?

Answer 5

Elderly, paediatric and neonatal patients, and those with kidney failure

Question 6

For the antibiotic to be effective, what to factors come into play?

Answer 6

The BREAK POINT (chosen concentration (mg/L) of an antibiotic which defines whether a species of bacteria is susceptible or resistant to the antibiotic) must exceed the MINIMUM INHIBITORY CONCENTRATION (the lowest concentration of a chemical that prevents visible growth of a bacterium)

Question 7

In which cases might prophylactic antimicrobial therapy be considered?

Answer 7

• Surgery - Prevention of IE - Post exposure prophylaxis eg. N. meningitidis

Question 8

When prescribing IV antibiotics, how often should they be reviewed?

Answer 8

Every 48 hours

Question 9

What are the indications for gentamicin?

Answer 9

Severe gram negative infections and bacterial endocarditis

Question 10

What antibiotics are used for serious staph. aureus infections?

Answer 10

Flucloxacillin

Question 11

What antibiotics are used for less serious staph. aureus infections?

Answer 11

Cephalosporins, clindamycin, erythromycin, lincomycin

Question 12

What antibiotics are used for MRSA infections?

Answer 12

VANCOMYCIN If nosocomial infection: Rifampicin and fusidic acid

Question 13

Which antibiotic targets the cell membrane, and what is it used for?

Answer 13

Colistin - used in infections with multi-resistant bacteria

Question 14

Which antibiotics target the cell wall?

Answer 14

Beta lactams - penicillins, cephalosporins, carbapenems

Question 15

How do beta lactams work?

Answer 15

BACTERICIDAL - Inhibit cell wall formation by preventing cross linking of peptoglycan

Question 16

How are beta lactams excreted?

Answer 16

Renally - alter dose in renal impairment

Question 17

Name 4 penicillins

Answer 17

Amoxicillin Penicillin V Flucloxacillin Piperacillin

Question 18

What is the best antibiotic for a staph aureus skin/soft tissue infection?

Answer 18

Flucloxacillin - only covers gram positives

Question 19

What antibiotic causes a widespread rash in glandular fever?

Answer 19

Amoxicillin

Question 20

What is co-amoxiclav used for?

Answer 20

Gram positive, negative and anaerobic cover - good soft tissue penetration

Question 21

What is amoxicillin used for?

Answer 21

Chest and ear infections Sometimes meningitis as it can cross the BBB

Question 22

What is tazocin used for?

Answer 22

Gram positive, negative and anaerobic cover - used in red flag sepsis, very unwell patients due to broad cover. Doesn’t get into the CNS!

Question 23

Name 3 cephalosporins

Answer 23

1st gen - cefalexin 2nd gen - cefuroxime 3rd gen - ceftriaxone The later the generation the better the GN cover but less GP cover

Question 24

What is cefalexin used for?

Answer 24

UTIs

Question 25

What is cefuroxime + metronidazole used for ?

Answer 25

Sepsis of unknown origin (IV)

Question 26

What is ceftriazone used for?

Answer 26

Meningitis!! Can cross BBB

Question 27

Name 2 carbapenems

Answer 27

Meropenem Ertapenem

Question 28

When are carbapenems used?

Answer 28

Very broad GN, GP and anaerobic cover Multi-drug resistant infections, and penicillin allergy

Question 29

What are the side effects of beta lactams?

Answer 29

Diarrhoea - could give C.diff! (the broader the cover, the higher the c diff risk) Deranged LFTs (coamoxiclav) Rash (amoxicillin)

Question 30

Which antibiotics target the cytoplasm?

Answer 30

Metronidazole and daptomycin

Question 31

What is metronidazole used for?

Answer 31

Bactericidal against anaerobes (clostridium) and protozoa

Question 32

What does metronidazole react with?

Answer 32

Alcohol

Question 33

What antibiotics target the ribosome?

Answer 33

Macrolides Clindamycin Aminoglycosides Tetracyclines Linezolid Chloramphenicol

Question 34

Give 3 examples of macrolides

Answer 34

Clarithromycin, erythromycin and azithromycin

Question 35

What are macrolides used for?

Answer 35

Pneumonia - to cover atypical organisms (give amox + clarithromycin)

Question 36

What are the side effects of macrocodes?

Answer 36

Caution in renal and liver failure Prolong QT interval Increase warfarin/phenytoin levels (P450 inhibitors) GI upset Rash

Question 37

What is clindamycin used for?

Answer 37

Toxic shock Nec fasc

Question 38

What is doxycycline used for?

Answer 38

Travellers diarrhoea, chlamydia

Question 39

When is doxycycline contraindicated?

Answer 39

Children under 12 Pregnancy Breastfeeding

Question 40

Give an example of an aminoglycoside, and what is it used for?

Answer 40

Gentamicin Wide spectrum but poor - use in combo Use for IE

Question 41

What are the side effects of gentamicin

Answer 41

Ototoxicity, renotoxic, myasthenia gravis reaction

Question 42

Which antibiotics target the chromosome?

Answer 42

Quinolones Trimethoprim Nitrofurantoin

Question 43

Give an example of a quinolone and its contraindications?

Answer 43

Ciprofloxacin Dont use in renal/hepatic failure, epilepsy, children or elderly (c diff risk)

Question 44

What is trimethoprim used for and when is it contraindicated?

Answer 44

UTI Not in renal failure, antifolate drugs (methotrexate), pregnancy

Question 45

When is nitrofurantoin used and when is it contraindicated?

Answer 45

UTI Not for pyelonephritis (conc not high enough), renal failure, infants, or pregnancy 3rd trimester (haemolysis risk)

Question 46

Which antibiotics require therapeutic monitoring routinely?

Answer 46

1. Gentamicin and vancomycin (IV) - narrow therapeutic index 2. Long term treatment 3. Renal impairment 4. Compliance issues

Question 47

When should gentamicin and vancomycin levels be measured and what is the target?

Answer 47

Trough level ie. just before the next dose Gent - aim below 1 or 2mg Vanc - aim between 10-15mg

Question 48

How should a patient with cellulitis be treated: a) hospital b) inpatient

Answer 48

a) IV flucloxacillin (+- ben pen) b) IV ceftriaxone Alternatives - clindamycin, daptomycin

Question 49

What is the adverse effect associated with: a) clindamycin b) daptomycin

Answer 49

a) c. diff b) rhabdomyolysis

Question 50

What is the most appropriate management of meningitis?

Answer 50

GP: IM ben pen Hospital: IV ceftriaxone (stat) Consider corticosteroids if bacterial IV fluids

Question 51

How should household contacts of meningitis be treated prophylactically?

Answer 51

Rifampicin over 2 days Ciprofloxacin stat Ceftriaxone stat (in pregnancy)

Question 52

What bacteria cause meningitis in: a) younger patients b) older patients and how does this alter management

Answer 52

a) N. meningitidis (5 days abx) b) strep pneumonia (10-14 days abx + steroids)

Question 53

What is the most common pathogen in patients with IE? a) native valve b) prosthetic valve and how should each be treated?

Answer 53

a) Strep viridans - benpen + gentamicin b) staph aureus - fluclox + vancomycin

Question 54

Should people get IE prophylaxis, and if so what should they get?

Answer 54

Only those with risk factors (heart disease) who are undergoing dental procedure or GI surgery Amoxicillin or clindamycin

Question 55

What are the side effects of vancomycin?

Answer 55

Red man syndrome, ototoxicity, GI upset