Protein Synthesis Inhibitors

Question 1

Tetracyclines MOA

Answer 1

Binds to 30s subunit of bacterial chromosome inhibiting bacterial protein synthesis. These are broad spectrum abx, covering the whole range.

Question 2

Tetracycline resistance

Answer 2

Any organism resistant to one tetracycline is resistant to all tetracyclines.
Not used when suspecting staph A.

Question 3

Tetracycline pharmacokinetics

Answer 3

Taking with dairy foods decreases absorption

All of these cross placental barrier and concentrate in fetal bones and dentition

Question 4

Can doxycycline be used in renal compromised patients?

Answer 4

Yes, because its metabolite is excreted vie bile in the feces and is not reabsorbed in the renal tubules.

Question 5

Tetracyclines effect on calcified tissue

Answer 5

Deposits into developing bone and teeth, discoloring teeth and stunting growth in children.

Question 6

Tetracyclines also cause….

Answer 6

Phototoxicity - severe sunburn

Vestibular problems: dizziness, nausea

Question 7

Tetracyclines CI

Answer 7

Pregnancy/lactation
Children under 8
Impaired renal fxn (except doxy)
Caution if impaired liver fxn
Caution if SLE

Question 8

Doxycycline uses

Answer 8

mycoplasma pneumoniae
chlamydiae
rickettsiae (spotted fever)
Lyme DIsease

Question 9

Doxy dose

Answer 9

100mg BID

Question 10

Macrolide MOA

Answer 10

Binds irreversibly to the 50S subunit of the bacterial ribosome, inhibiting protein synthesis

Question 11

Erythromycin action

Answer 11

effective against penicillin G organisms. Also effective against chlamydial species and mycoplasma pneum.

Question 12

Clarithromycin (Biaxin)

Answer 12

Similar to erythromycin but also H. Flu.

Question 13

Azithromycin (Zithromax)

Answer 13

Less active against streptococci and staph but more active against resp infxns from H. Flu, moraxella catarrhalis, excellent for chlamydia trachomis.

Question 14

Macrolides and Tetracyclines arent used against…

Answer 14

Staph Aureus

Question 15

Erythro is p450 so it…

Answer 15

interacts with other drugs

Question 16

Azithro is not p450

Answer 16

believe it

Question 17

erythro and azithro are excreted via?

Answer 17

bile, no adjustments need to be made for renal

Question 18

Chloramphenicol

Answer 18

Very toxic, wide spectrum abx.

Use restricted only for life-threatening infections

Question 19

Gray baby syndrome

Answer 19

caused by chloramphenicol and kills babies.

Question 20

Clindamycin

Answer 20

Great anaerobic converage and also active against gram+ cocci.
Does not absorb into CSF
Used to treat penetrating gut wounds

Question 21

Clostridium difficile is always resistant to_____?

Answer 21

Clindamycin, can cause secondary infxn.