Antibiotics: protein synthesis inhibitors

Question 1

Aminoglycosides?

Answer 1

Mechanism of action:

• Binds to 30S subunit causing misreading of mRNA

Adverse effects:

• Nephrotoxicity, Ototoxicity

Question 2

Tetracyclines?

Answer 2

Mechanism of action:

• Binds to 30S subunit blocking binding of aminoacyl-tRN

Adverse effects:

• Discolouration of teeth, photosensitivity

Question 3

Chloramphenicol?

Answer 3

Mechanism of action:

• Binds to 50S subunit, inhibiting peptidyl transferase

Adverse effects:

• Aplastic anaemia

Question 4

Clindamycin?

Answer 4

Mechanism of action:

• Binds to 50S subunit, inhibiting translocation (movement of tRNA from acceptor site to peptidyl site)

Adverse effects:

• Common cause of C. difficilediarrhoea

Question 5

Macrolides?

Answer 5

Mechanism of Action:

• Binds to 50S subunit, inhibiting translocation (movement of tRNA from acceptor site to peptidyl site)

Adverse effects:

• Nausea (especially erythromycin), P450 inhibitor, prolonged QT interval

Notes:

• Commonly used for patients who are allergic to penicillin