Macrolides

Question 1

Name 3 Macrolides:

Answer 1

Azithromycin
Erythromycin
Clarithromycin

Question 2

Are macrolides Bactericidal or bacteriostatic?

Answer 2

Bacteriostatic

Question 3

Prototype drug in Macrolide group

Answer 3

Erythromycin

Question 4

Azithromycin is derived from

Answer 4

Erythromycin

Question 5

Due to drug interactions and side effects of Erythromycin and clarithromycin

Answer 5

Azithromycin is preferred and is the majority of macrolide use

Question 6

Macrolides exhibit

Answer 6

Immunomodulating properties (useful in infectious diseases and cystic fibrosis)

Question 7

Macrolide MOA

Answer 7

Bind to 50s ribosomal subunit to inhibit protein synthesis

Question 8

Azithromycin is used for:

Answer 8

Chancroid
Chlamydia in pregnant patients
Gonorrhea if patient has cephalosporin allergy

Chronic bronchitis, sinusitis, CAP, Pharyngitis, and tonsillitis

Uncomplicated skin soft tissue infections

Chlamydia trachomatis and gonorrhea

Travelers diarrhea

Question 9

Erythromycin Indications

Answer 9

CAP, bronchitis, pertussis

Impetigo cellulitis

Neonatal conjunctivitis caused by (N. gonorrhoeae or chlamydia trachomatis)

Chlamydia

Prophylaxis for rheumatic fever in those with penicillin allergies

Bacterial endocarditis for dental or surgical procedures

Question 10

Macrolides absorption

Answer 10

Well-absorbed from the duodenum with oral administration

Minimal absorption from topical or ophthalmic use

Question 11

Macrolide Distribution

Answer 11

Readily to body tissues

Enters pleural fluid, ascitic fluid, middle ear exudates, and sputum.

Meninges if they are inflamed

Enter CSF

Question 12

Macrolide Metabolism

Answer 12

partially by the liver

Question 13

Macrolide excretion

Answer 13

mainly unchanged in the bile, also unchanged in the urine

Question 14

Both Erythromycin and Clarithromycin have a higher number of
drug interaction due to? What medication should be stopped if taking either abx?

Answer 14

being strong inhibitors of the CYP enzymes (CYP3A4)

HMG-CoA Reductase Inhibitors (Statins) should be stopped while on
either due to risk of severe myopathy or rhabdomyolysis

Question 15

Erythromycin is heavily metabolized by

Answer 15

CYP3A4 which explains its many drug interactions

Question 16

Erythromycin contraindicated in patients with?

Answer 16

Preexisting liver disease

Question 17

Azithromycin should be used with caution in these patients:

Answer 17

Patients with hepatic dysfunction

Question 18

What EKG change has been observed?

Answer 18

QT interval

Question 19

Macrolide ADRs

Answer 19

Dose-related GI symptoms, including nausea, vomiting, abdominal pain, cramping, and diarrhea.

Question 20

Azithromycin and erythromycin ADRs

Answer 20

Associated with liver abnormalities, including hepatitis, cholestatic jaundice, and hepatic failure.

Question 21

What’s the major reason selecting azithromycin over other macrolides?

Answer 21

Enhanced compliance due to convenient once a day dosing for 3 to 5 days, missing one day could cause unsuccessful treatment.

Question 22

Macrolide Resistance

Answer 22

(1) reduced permeability of the cell membrane or active efflux,
(2) modification of the ribosomal binding site by chromosomal mutation, or
(3) production of esterase by Enterobacterales that hydrolyze macrolides.