Protein Synthesis Inhibitors (Tetracyclines )

Question 1

What are Protein Synthesis Inhibitors?

Answer 1

1. Tetracyclines
2. Aminoglycosides
   3.Macrolides &Ketolides
   4.Chloramphenicol
   5.Clindamycin
   6.Oxazolidinones

Question 2

Tetracycline class include :

Answer 2

-Minocycline
-Doxycycline
-Demeclocycline
-Tetracycline

Question 3

MOA for tetracyclines :

Answer 3

-Rversible binding with 30S subunit of bacterial Ribosome preventing binding of tRNA with mRNA

Question 4

Tetracyclines are ……………………. Antibiotic , and are effective for …….. , ……….., ………….,…………..and ……….. .

Answer 4

Bacteriostatic / Gram + , Gram - , protozoa , spirochetes and atypical.

Question 5

Tetracycline is prescribed in

Answer 5

Peptic ulcer disease

Question 6

Doxycycline is prescribed in : ( 6 cases )

Answer 6

1. Acne
2. Cholera
3. Rocky Mountain Spotted Fever
4. Lyme disease
5. Chlamydia
6. Mycoplasma Pneumonia

Question 7

MOR for Tetracycline :

Answer 7

1) Efflux pump
2) Enzymatic inactivation of the drug
3) Interfering with binding to ribosomes

Question 8

……………. Is not a common mechanism of resistance of tetracyclines

Answer 8

Cross-Resistance

Question 9

How are tetracyclines taken?

Answer 9

Orally

Question 10

Rate of absorption

Answer 10

Tetracycline are adequately absorbed but it is decreased if it is administered with dairy ( high cations )

Question 11

Why is the rate of absorption of tetracyclines decreased when it is administered with cations ?

Answer 11

Because they form non- absorbable chelates.

Question 12

Where are tetracyclines distributed ?

Answer 12

1) body fluids including CSF
2) bind to tissues undergoing calcification ( bone ,teeth )
3) Cross placenta and deposit in fatal bones during pregnancy

Question 13

How are tetracyclines eliminated ?

Answer 13

They are eliminated unchanged in urine

Question 14

How are doxycyclines eliminated ?

Answer 14

In bile /feces

Question 15

What are the adverse effects of tetracyclines ?

Answer 15

1) Pseudotumor cerebri
2) Vestibular Dysfunction
3) Effects on calcified tissues
4) Gastric discomfort
5) Hepatotoxicity
6) Phototoxicity

Question 16

Vestibular dysfunction and tetracyclines :

Answer 16

Dizziness, vertigo , tinnitus

Question 17

Gastric discomfort and tetracyclines :

Answer 17

Irritation of gastric mucosa and esophagitis

Question 18

Calcified tissues and tetracyclines :

Answer 18

They generally deposit in tissues undergoing calcification , they may cause dental hypoplasia and growth problems .

Question 19

Phototoxicity and tetracyclines :

Answer 19

They may cause severe sunburns

Question 20

Tetracyclines contraindications :

Answer 20

1) Pregnant women
2) Breast-feeding women
3) Pediatric age group <8 years

Question 21

Glyclcyclines include ……..

Answer 21

Tigecyclines

Question 22

About Tigecyclines :

Answer 22

-Derivative of minocyclines
- Same mechanism of action and mechanism of resistance as tetracyclines

Question 23

Antibacterial Spectrum of Tigecyclines:

Answer 23

1) MRSA
2) Vancomycin-resistance enterococci
3) Multi-drug resistance streptococci
4) ESBL gram-negative bacteria
5) Acinetobacter species
6) Pseudomonas