50 S Protein Synthesis Inhibitors

Question 1

Macrolides

large LACTONE ring

Answer 1

Erythromycin
Azithromycin
Clarithromycin
Telithromycin
Roxithromycin

Question 2

Macrolides Coverage

Answer 2

gram (+)
gram (-)
atypical

NO pseudomonas and anaerobic coverage

Question 3

Treatment of disseminated MAC in AIDS

Answer 3

Clarithromycin

Question 4

All Macrolides exhibit TIME DEPENDENT KILLING EXCEPT

Answer 4

Azithromycin - concentration dependent

*can cause ARRYTHMIA

Question 5

Erythromycin stimulates

Answer 5

MOTILIN RELEASE – INC PERISTALSIS – DIARRHEA

Question 6

Prophylaxis against disseminated MAC in AIDS

Answer 6

Azithromycin

Question 7

More potent than erythromycin d.t. additional methyl group

Answer 7

Clarithromycin

*has greater activity against H. pylori, M.avium complex, T. gondii

Question 8

LINCOSAMIDES

Answer 8

Clindamycin

Lincomycin

Question 9

SULFUR containing antibiotics isolated from Streptomyces lincolnensis

Notorious for causing STEVEN JOHNSON SYNDROME

Answer 9

Lincomycins

Question 10

Against non-spore forming anaerobic bacteria (Bacteroides fragilis)

Answer 10

CLINDAMYCIN

*AE - pseudomembranous enterocolitis

Question 11

Coverage of Clindamycin

Answer 11

gram (+)
CA - MRSA
anaerobic organisms

CLINDAMYCIN - anaerobic infections ABOVE the diaphragm except the brain

METRONIDAZOLE - anaerobic infections BELOW the diaphragm including the BRAIN

Question 12

Causes APLASTIC ANEMIA (bone marrow suppression) and Gray Baby syndrome

Answer 12

Chloramphenicol

Question 13

Gray color/cyanosis, vomiting, flaccidity, hypothermia, shock

Answer 13

Gray Baby syndrome

LIMIT DOSE (Chloramphenicol) - < 50 mg/kg/d during the 1st week of life

premature neonates - DEFICIENT in hepatic GLUCURONOSYLTRANSFERASE

Question 14

What metabolic pathway is effective in detoxifying chloramphenicol?

Answer 14

Glucuronidation reaction ( Type of phase 2 reaction)

Question 15

Established mechanisms of resistance of gram (+) organisms to macrolide antibiotics

Answer 15

Methylase production

Methylation of the receptor site

Question 16

SE of Macrolides

Answer 16

GI Upset
QT prolongation
Cholestatic hepatitis

Question 17

ALL macrolides INHIBIT CYP450 EXCEPT

Answer 17

Azithromycin

Question 18

Macrolide with highest Vd and slowest elimination

Answer 18

Azithromycin

Question 19

Streptogramins

for drug resistant gram (+) cocci – Staphylococci and E. faecium (MRSA, VRSA, VRE)

Answer 19

Quinupristin-Dalfopristin

SE: arthralgia-myalgia syndrome

Question 20

Oxalidinone

binds to 23s ribosomal RNA of 50s subunit

for drug resistant gram (+) cocci – Staphylococci and E. faecium (MRSA, VRSA, VRE), Listeria, Corynebacteria

Answer 20

Linezolid

Tedizolid

Question 21

SE of Chloramphenicol

Answer 21

Gray baby syndrome
Aplastic anemia (idiosyncratic)

Question 22

Chloramphenicol resistance is d.t.

Answer 22

Formation of acetyltransferase that inactivates drug

Question 23

Characterized by DECREASED RBC, cyanosis and cardiovascular collapse

Answer 23

Gray Baby Syndrome

Premature neonates are deficient in hepatic GLUCORONOSYLTRANSFERASE

Glucuronidation - the way to metabolize chloramphenicol