L26: Tetracyclines/Macrolides

Question 1

Which of the following is NOT a Macrolides?

A. Erythromycin
B. Clarithromycin
C. Azithromycin
D. Tetracycline

Answer 1

D. Tetracycline

Question 2

Tigecycline belongs to which group?
A. Ketolides
B. Macrolides
C. Tetracyclines
D. Glycylcyclines

Answer 2

D. Glycylcyclines

Question 3

Which of the following is targeted by tetracyclines and aminoglycosides?
A. 30 S
B. 50 S

Answer 3

A. 30 S

Question 4

Tetracyclines are considered
_____, meaning host
immune system required to
finish off infection
A. bacteriostatic
B. bacteriocytic
C. bacteriocidal

Answer 4

A. bacteriostatic

Question 5

How to tetracyclines enter bacteria??

Answer 5

Passive diffusion / Active transport

Question 6

True or False: Tetracyclines reversibly bind 30S to block binding of next aminoacyl-tRNA to the ribosome

Answer 6

True

Question 7

What are the two primary uses of tetracyclines?

Note: broad spectrum

Answer 7

1) Acne
2) Chlamydial infections

Question 8

Why are tetracyclines not usually a drug of choice for many gram (+) aerobic infections??

Answer 8

Resistance with Staphylococci, Streptococci and
some Pneumococci

Question 9

Which gram (-) bacteria / Anaerobes are resistant to tetracycline?

Answer 9

Gram (-)
- Pseudomonas
- Enterobacteriaceae

Anaerobes
B. fragilis

Question 10

True or False: Brucella, Vibrio Cholera can be treated with tetracycline

Answer 10

True

Question 11

Minocycline microspheres is a type of tetracycline that is used to treat ___ disease

Answer 11

peridontal

Question 12

Why are tetracyclines minimally used?

Answer 12

Because large number of bacterial strains are resistant

Question 13

Which conditions does doxy primarily used to treat?

Answer 13

1) Skin/Soft Tissue infections (MRSA)
2) Chlamydia

Question 14

________: tetracycline-resistant strains; skin and abdominal infections; Proteus and Pseudomonas are resistant

A. Tigecycline
B. Tetracycline
C. Clarithromycin
D. Doxycycline

Answer 14

A. Tigecycline

Question 15

True or False: Tetracycline is concentration + time dependent killing (maximize AUC)

Answer 15

True

Question 16

True or False: Tetracycline crosses placental barrier (pregnancy category D); excreted in breast milk

Answer 16

True

Question 17

Doxycycline and tigecycline are eliminated by _____
mechanisms - important for patients with kidney failure or co-
administered nephrotoxic drugs

Answer 17

non-renal

Question 18

AE associated with Tetracyclines?

Answer 18

1) Teeth
- discoloration
- enamel dysplasia in teeth
- reduced growth/deformities

2) Superinfections - C. diff

3) Skin sensitivity to sunlight

4) Nephrotoxicity
- Fanconi syndrome can result from use of degraded tetracycline

• do not dose with dairy

Question 19

True or False: Under no circumstances should expired tetracycline be used

Answer 19

True

Question 20

What are two ways to avoid drug resistance (tetracyclines)?

Answer 20

1) Impaired drug influx or increased
efflux via active membrane
transporters

2) Expression of proteins that interfere
with drug binding to 30S ribosomal
subunit