3.4 - Inhibition of Protein Synthesis

Question 1

What antibiotics inhibit protein synthesis in the microorganism?

Answer 1

–> Aminoglycosides
–> Macrolides
–> Tetracyclines
–> Chloramphenicol

Question 2

What are the names for the top and bottom portion of a ribosome?

Answer 2

Top: 50S
Bottom: 30S

Question 3

Where do aminoglycosides act?

Answer 3

By changing the shape of 30S

Question 4

What kind of drugs are gentamicin and tobramycin?
What are they used to treat?
Are they charged or uncharged? How are they administered?
Adverse effects?

Answer 4

Aminoglycosides
–> Gram- aerobic
–> Charged
–> i.v or i.m.
–> Nephrotoxicity and ototoxicity

Question 5

What is ototoxicity?

Answer 5

A drug that can cause damage to the auditory or vestibular functions of the ears.

Question 6

What kind of drugs are clarithromycin and azithromycin*?
What kind of bacteria and infections do they treat?
Adverse effects?

Answer 6

Macrolides
–> Gram + (Useful substitute for penicillin if people display hypersensitivity)
–> Respiratory infections, (chlamydia, gonorrhea)*
–> NV&D

Question 7

Where do macrolides act on the ribosome?

Answer 7

Binds to 50S and prevents translocation-movement of ribosome along mRNA

Question 8

What are some adverse effects specific to clarithromycin?

Answer 8

Inhibit hepatic (p450s) enzymes
–> Risk of toxicity for any drug normally metabolized and inactivated by the liver

Question 9

Which drugs act on 50S?

Answer 9

Macrolides:
–> Azithromycin
–> Clarythromycin

–> Linezolid
–> Clindamycin

–> Chloramphenicol

Question 10

What class of drug is clindamycin? What is it used to treat?

Answer 10

Lincosides (acts like macrolides)
–> Used to treat soft tissue infections (Cellulitis, bites), especially for allergy to beta-lactams and bacterial vaginosis

Question 11

What class of drug is linezolid? What is it used to treat?

Answer 11

Member of oxazolidinones
–> used to treat infections that are otherwise resistant to VRE and MRSA

Question 12

Where on the ribosome do tetracyclines act?

Answer 12

30S
–> Interferes with attachment of tRNA to mRNA-ribosome complex

Question 13

Where on the ribosome does chloramphenicol act?

Answer 13

binds to 50S portion and inhibits formation of peptide bond

Question 14

What kinds of drugs are tetracyline, doxycycline, and minocycline?
What are they used to treat?
Precautions?

Answer 14

Tetracyclines
–> Broad spectrum; widespread resistance
–> High affinity for bone and teeth, interacts with milk, antacids, calcium, and iron (decrease drug absorption)
–> Risk of superinfections
–> Photosensitivity
–> Avoid if pregnant

Question 15

What specific infections is tetracycline used to treat?

Answer 15

Acne & H. Pylori

Question 16

What specific infection is doxycycline used to treat?

Answer 16

Chlamydia

Question 17

What antibiotic interacts with milk, antacids, iron, and calcium, and therefore have a high affinity for bone and teeth?

Answer 17

Tetracyclines
–> Discoloration of teeth between 4 months to 8 years of age

Question 18

What are some precautions of chloramphenicol?
Why and what do we still use it for?

Answer 18

It was widespread resistance, and suppresses bone marrow functions in some individuals(anemia, bleeding issues, immunosuppression), newborns lack the enzymes to conjugate drug (phase two) and can cause cyanosis;
but, it is broad spectrum and has good distribution to the brain.
–> Rickettseal disease
–> Meningitis
–> Typhoid fever
–> Cholera

Question 19

What drug causes gray baby syndrome?

Answer 19

Toxic accumulation of chloramphenicol causes cyanosis in newborns because they lack the enzymes to conjugate the drug during metabolism

Question 20

What is agranulocytosis?

Answer 20

Low granulocytes

Question 21

What is thrombocytopenia?

Answer 21

Low platelet count