Protein Syntheis inhibitors

Question 1

Which Drug and adverse effect pairing is correct? She likes these types of questions**
A erythromycin : CNS toxicity
B. Chloramphenicol : cholestatic hepatitis
C. gentamicin : gray baby syndrome
D. doxycycline : tooth discoloration
E. mupirocin : renal toxicity

Answer 1

D

Question 2

what ribosome subunits do bacteria use?

Answer 2

50s and 30s. (70s ribosome-similar to mitochondria - toxicity)

Question 3

Tetracyclins, Tigecycline, Aminoglycosides, and Spectinomycin all act on what?

Answer 3

30S ribosome

Question 4

Most protein synthesis inhibitors are

Answer 4

bacteriostatic, given orally, and broad spectrum

Question 5

Tetracylcines

Answer 5

bind to 30S. very broad; superinfections! bacteriostatic

Question 6

Tetracyclines cont.

Answer 6

decrease by divalent and trivalent cations (Fe and K) so they shouldn’t have food at same time. absorption is decreased when pH is elevated.

Question 7

Which is False. Tetracyclines have narrow distribution, have good penetration into the CNS, and are deposited in bone, dentine, and enamel

Answer 7

They have a WIDE distribution in the body

Question 8

Doxycyclines and monocyclines are always the exception to tetracyclines

Answer 8

namely they are eliminated in the feces so they don’t have an impact on the normal flora=makes them safer

Question 9

Uses of tetracyclines

Answer 9

Acne, Drug of choice for treatment of rickettsial disease

Question 10

Adverse effects of tetracyclines

Answer 10

pseudomembranous colitis, discoloration of teeth and fetal childhood risks, bluing of tissue, DO NOT give to pregnant women and children

Question 11

tetracyclines should be used with cidal antibiotics like penicills. true or false

Answer 11

false. drug interactions between tetracycline and bacteriocidal drugs.

Question 12

Tigecycline

Answer 12

similar mechanism of action to tetracyclines, but binds higher affinity to 30s ribosome. . used for strains that are tetracycline resistant and some MRSA.

Question 13

Aminoglycosides

Answer 13

Gentamicin. ***Bactericidal! bind irreversible to 30S ribosome. concentration dependent killing with significant PAE (uncommon)

Question 14

Uses of Aminoglycosides

Answer 14

Primarily gram negative aerobic bacilli. synergistic Combination therapy with penicillin or vancomycin (acts synergistically on staph aureus and epidermidis

Question 15

Toxicities of Aminoglycosides

Answer 15

Ototoxicity (irreversible loss of hearing) and renal toxicities. also vestibular toxicities

Question 16

Gentamicin

Answer 16

aminoglycoside. resistance is due to poor drug uptake. synergistic with penicillins and vancomycin. Main use is SEVERE gram - infections. ototoxicity, vestibular, and renal damage

Question 17

What is false about spectinomycin
It binds to the 50S subunit
It works mostly on gram negatives but some gram + as well.
Main use is for antibiotic resistant gonorrhea and MRSA
It is bacteriostatic

Answer 17

It works on the 30S subunit, not the 50S.

Question 18

What class are azithromycin, erythromycin, and clarithromycin in?

Answer 18

Macrolides. erythromycin is founding member. azi and clar have better distribution and absorption

Question 19

Macrolide target

Answer 19

50S subunit very close to same site as streptogramin, slindamycin, and chloramphenicol. Competitively inhibits them/Antagonism

Question 20

What is false about macrolides
Binds reversibly to the 50S subunit
its bacteriostatic
Have a broad spectrum of activity
Organisms build rapid cross-resistance to it

Answer 20

They have a narrow spectrum of activity.

Question 21

MLS-type B resistance

Answer 21

macrolide lincosamide streptogramin. expresses methylase that modifies the bacterial ribosome and drug is unable to bind

Question 22

Erythromycin

Answer 22

not acid stable like the other macrolides (azithromycin, clarithromycin),

Question 23

Uses of macrolides

Answer 23

good substitution for penicillins in allergic patients. Also acne.

Question 24

what is the key weakness of the macrolides?

Answer 24

resistance develops rapidly

Question 25

Adverse effects of macrolides

Answer 25

Gi disturbances is the main problem. can cause cholestatic hepatitis
interacts with other drugs (azithromycin avoids this drug interations.

Question 26

Ketolides

Answer 26

Telithromycin. binds to 50S ribosome, less resistance. Bacteriostatic .

Question 27

Uses of ketolides (telithromycin)

Answer 27

community acquired RTI (pneumonia). acute bacterial sinusitis, chronic bronchitis

Question 28

adverse effects of telithromycin

Answer 28

Exacerbation of disease symptoms in myasthenia gravis patients

Question 29

Chloramphenicol

Answer 29

bacteriostatic, binds 50S ribosome. binds close to clindamycin and macrolides. VERY broad spectrum of activity

Question 30

What is the main adverse effect of Chloramphenicol?

Answer 30

Gray baby Syndrome.

- can’t metabolize the drug; vomit, cyanosis, ashen color, flaccid, hypothermic. 40% mortality

Question 31

Drug interactions of chloramphenicol

Answer 31

Inhibits liver enzymes and increases half life of other drugs

Question 32

Streptogramins/Synercid/(quinupristin/dalfopristin)

Answer 32

dalfopristin binds nearby the site of macrolides. It enhances quinupristin binding = Synergism

Question 33

Synercid action

Answer 33

quinupristin and dalfopristin together synergistically increase binding of one another and causes bactericidal activity in an otherwise static drug

Question 34

main uses of Synercid

Answer 34

MRSA, Vancomycin resistant gram + infections. VREF, VRSA, Streptococcus pneumoniae

Question 35

LInezolid

Answer 35

binds to 23S ribosomal RNA. no cross resistance with other protein synthesis inhibitors. used for serious infections like MRSA, VREf, multi-drug resistance