Tetracyclines and Macrolides

Question 1

What can tetracyclines produce (3 toxicities)

Answer 1

1. Renal tubular acidosis
2. azotemia
3. Fanconi’s syndrome (from outdated preps).

Question 2

How are tetracyclines excreted?

Answer 2

All are excreted as nephrotoxic metabolites by the kidney except doxycycline (excreted in feces).

Question 3

What is the only tetracycline that is NOT excreted by the kidneys?

Answer 3

Doxycycline (so no renal side effects with it)

Question 4

What to use for UTIs in women with risk factors for STDs? (2)

Answer 4

Doxycycline (except if E. Coli b/c resistant)

Azithromycin

Question 5

Tetracyclines - MOA

Answer 5

Antimicrobial

Prevent tRNA binding to 30S

Question 6

Tetracyclines - name 5

Answer 6

Older tetracycline (e.g. demeclocycline) 
Doxycycline 
Minocycline 
Glycylcycline 
Tigecycline

Question 7

Tetracyclines - MOR (3)

Answer 7

influx/efflux, binding site mutation, inactivation

Question 8

Tetracyclines - SE (5)

Answer 8

1. GI (diarrhea, vomiting)
2. Photosensitivity
3. Brown teeth for fetus/young children, neuromuscular blockade (Ca2+ chelation)
4. Nephrotoxicity (renal tubular acidosis, azotemia, Fanconi’s syndrome)

Question 9

Name 3 macrolides

Answer 9

Azithromycin; Clarithromycin; Erythromycin

Question 10

Azithromycin; Clarithromycin; Erythromycin - Class

Answer 10

Antimicrobials- macrolides

Question 11

Azithromycin; Clarithromycin; Erythromycin - MOA

Answer 11

Binds 50S peptidyltransferase to block translocation

Question 12

Azithromycin; Clarithromycin; Erythromycin - Tx

Answer 12

Use in women w/ UTIs and risk factors for STDs (especially Chlamydia)

Question 13

Which one of the macrolides do not have a high cellular concentration?

Answer 13

Erythromycin

Question 14

How would you describe the distribution of macrolides?

Answer 14

All have large tissue distribution

Question 15

Azithromycin; Clarithromycin; Erythromycin - MOR (2)

Answer 15

Efflux pumps

These drugs induce methylation of 50S and cannot bind –> cause resistance to self

Question 16

Azithromycin; Clarithromycin; Erythromycin - Tox (4)

Answer 16

Hypersensitivity
GI problems
Arrhythmia (QT prolongation)
Hepatitis (erythromycin)

Question 17

Azithromycin; Clarithromycin; Erythromycin - Drug Interactions

Answer 17

Decrease cytP450s (except for azithromycin)