Beta-lactams

Question 1

Mode of action

Answer 1

• Attach to penicillin binding proteins on bacteria and inhibit the transpeptidase enzyme activity that catalyses the cross-linking of NAMA and NAG
• Inactivate the inhibitor of autolytic enzymes in the cell wall leading to cell lysis

Question 2

Pharmacokinetics

Answer 2

renally excreted, short half-life, widely distributed in body fluids

Question 3

Benzylpenicillin

Answer 3

bacterial meningitis, beta-hemolytic strep, septic arthritis, moderate pneumonia, strep pharyngitis, tonsillitis, severe soft tissue infection

Question 4

Amoxicillin

Answer 4

Resp infections, UTI, otitis media, sinusitis

Question 5

Flucoxacillin

Answer 5

Cellulitis, endocarditis, bone and joint infection

Question 6

Piperacillin

Answer 6

Severe sepsis, pseudomonal infections, pyrexia in neutropenic cancer chemotherapy patients

Question 7

Co-amoxiclav

Answer 7

Intrabdominal infection, complicated ENT infections

Question 8

Adverse effects

Answer 8

Hypersensitivity, diarrhoea, anaphylaxis

Question 9

Cefotaxime/Ceftriaxone

Answer 9

Bacterial menigitis, ceftriaxone - gonorrhea, soft tissue infection (OPAT)

Cefotaxime - acute epiglotitis

Question 10

Ceftazidime

Answer 10

Brochiectasis, anti-pseudomonal activities

Question 11

Aztreonam

Answer 11

Monobactam, only active against gram-negatives (eg. pseudomonas), safe to give to patients with life-threatening allergy to penicillin

Bronchiectasis, Cystic fibrosis

GI upsets

Question 12

Meropenem (carbapenem)

Answer 12

Antibiotic of last resort, given to patients with cancer, structural lung disease, ICU,

Septic shock (together with gentamicin)

GI upsets

Question 13

Ertapenem

Answer 13

UTI (OPAT), once daily IV

GI upsets

Question 14

Cefuroxime

Answer 14

Surgical prophylaxis (second-generation cephalosporin)