JAL L4 β-Lactams

Question 1

R group of penicillins determines…. (5)

Answer 1

Selectivity (small enough to reach g-ve through porins)
Solubility (Na+ and K+ salts more soluble)
Stability (degrades in stomach pH?)
Bioavailability
β-Lactamase resistance

Question 2

e.g. of β-Lactamase sensitive? (2)

Answer 2

Pen G

Penicillin V

Question 3

e.g. of β-Lactamase resistant? (2)

Answer 3

Flucloxacillin: co-fluampicil
&
Temocillin (also resistant to G-ves)

Question 4

e.g. of broad spectrum (2)

Answer 4

amoxicillin

ampicillin

Question 5

e.g. of antipseudomonal (2)

Answer 5

piperacillin + tazobactam: Tazocin

Question 6

Pen G is also called

Answer 6

benzylpenicillin

Question 7

Pen G is orally active?

Answer 7

No

Question 8

Does pen G have good distribution?

Answer 8

Yes into tissues and fluids, not into CSF (unless meningitis)

Question 9

Pen G lasts for a long time?

Answer 9

Rapid excretion into the urine but long post antibiotic effect

Question 10

To maintain Pen G levels we might:

Answer 10

• give larger doses
• frequent dosing
• combine with slow IM (benzathine benzylpenicillin)

Question 11

Uses of Pen G (6)

Answer 11

Throat infections
Meningitis
Pneumonia
Cellulitis
Osteomyelitis
Endocarditis (high dose! therefore not toxic!)

Question 12

If meningitis suspected use………………. immediately

Answer 12

Pen G

Question 13

3 Causes of meningitis:

Answer 13

LEARN LEARN LEARN.
Neisseria meningitidis
Strep. pneumoniae
Haemophilus influenzae

Question 14

Ampicillin is oral because….

Answer 14

stable under acid conditions.

Question 15

PK of ampicillin….

Answer 15

=40% absorption

Good CSF levels in meningitis but usually IM or IV.

Question 16

Is there resistance to ampicillin

Answer 16

Yes
40% E.coli
Most staphylcocci

Question 17

What is ampicillin used to treat? (4)

Answer 17

Throat
Dental
Resp
UTI etc.

Question 18

S/e of penicillins (4)

Answer 18

HYPERSENSITIVITY
1-10% rash
0.05% anaphylaxis
-----
neurotoxicity
renal failure
oral can cause diarrhoea

Question 19

How does superinfection occur?

Answer 19

Oral broad spectrum antibiotics kill gut bacteria, resistant bacteria cause superinfection.
>diarrhoea
> C. diff

Question 20

Cephalosporins are resistant to β-Lactamases?

Answer 20

Yes, not ESBLs

Question 21

Cephalosporins are active against gram +/-ve?

Answer 21

originally +ve

now also -ve

Question 22

Cephalosporins treat:

Answer 22

similar to penicillins

Question 23

PK of cephalosporins?

Answer 23

Mostly IM or IV, some oral.
Low penetration CSF (except meningitis)
Renal excretion.

Question 24

Cephalosporins cause hypersensitivity in what % of penicillin allergic patients?

Answer 24

0.5-6%

Question 25

S/e Cephalosporins

Answer 25

Diarrhoea, nausea, C. diff.

Question 26

1st generation Cephalosporins such as ……….. have generally been replaced and are active against gram …

Answer 26

cefazolin, cefradine

MOST gram +ve

Question 27

2nd gen Cephalosporins such as ………… have increased resistance to β-Lactamases

Answer 27

cefaclor

and increase gram -ve spectrum

Question 28

2nd generation are used for…

Answer 28

severe infection & preventing infection after surgery

Question 29

3rd generation cephalosporins such as ….. are used for….

Answer 29

ceftriaxone

Everything: CAP, hospital acquired infections etc.

Question 30

Subset of 3rd generation such as ceftazidime are active against….

Answer 30

p. aeruginosa

Question 31

4th generation cephalosporins are used for (2)

Answer 31

severe infections and p. aeruginosa

Question 32

4th generation cephalosporins have broader spectrum but,…

Answer 32

more resistance to β-Lactamases

Question 33

Carbapenems work by….

Answer 33

inhibiting cell wall synthesis

Question 34

Carbapenems are resistant or not to β-Lactamases

Answer 34

Very resistant

Question 35

Carbapenems have broad or narrow spectrum?

Answer 35

Broad. Including Ps. aeruginosa (but not against MRSA)

Question 36

Carbapenems used for (5)

Answer 36

Use IV for:
septicaemia
HA pneumonia
Intra-abdominal infections
complicated UTI
skin and soft tissue infections

Question 37

Monobactams work by….

Answer 37

inhibiting cell wall synthesis

Question 38

Monobactams have broad or narrow spectrum?

Answer 38

Narrow - only gram -ve aerobes

Question 39

Monobactams are resistant or not to β-Lactamases?

Answer 39

Resistant

Question 40

Monobactams are used for…

Answer 40

septicemia and complicated UTI

Question 41

Monobactams cause penicillin allergy?

Answer 41

No, less likely