Protein Synthesis Inhibitors ( Macrolites And Ketolites )

Question 1

Macrolides and ketolides derivatives :

Answer 1

1) Azithromycin
2) Clarithromycin
3) Telithromycin
4) Erythromycin

Question 2

MOA of Macrolides and ketolides :

Answer 2

1) bind irreversibly to a site on the 50S subunit of bacterial ribosome thus inhibit translocation step
2) interfere with transpeptidation

Question 3

The binding sites of Macrolites and ketolites is ……………. Or ………………… the binding site of………. & …………… .

Answer 3

Identical / near / clindamycin / Chloreamphenicol

Question 4

Antibacterial spectrum of Macrolides and Ketolides

Answer 4

Bacteriostatic but at high dose it can be bactericidal

Question 5

Antibacterial Spectrum of Erythromycin:

Answer 5

Erythromycin can be an alternative drug to penicillin G in patients who have penicillin allergy

Question 6

Antibacterial spectrum ( Clinically ) of Ezithromycin :

Answer 6

• it is used in general to RTI except for S.pnemoniae because of acquired resistance.

Question 7

………………….. is less active against Sterptococci and staphylococci strains

Answer 7

Ezithromycin

Question 8

Antibacterial Spectrum of Clarithromycin :

Answer 8

Similar to erythromycin in addition to intracellular pathogens as haemophilus influenza and helicobacter pylori

Question 9

Clinical Spectrum of Macrolides :

Answer 9

1) Mycoplasma pneumonia
2) Corynebactrium diphtheria
3) Chlamydial infections
4) legionellosis
5) Mycobacerium Avium infections

Question 10

MOR against Macrolides and Ketolides :

Answer 10

1) Decreasing the affinity of the 50S subunit of bacterial ribosome
2) the presence of plasmid-associated erythromycin esterase in gram-negative bacteria
3) the presence of efflux pump
4) the inability of the organism to take up the anti-biotic

Question 11

Route of administration of Macrolides and ketolides :

Answer 11

Orally and IV
IV : Erythromycin and Azithromycin are available
Orally : enteric-coated tablets for erythromycin

Question 12

Distribution of Macrolides and ketolides :

Answer 12

Distribute well in body fluids except for CSF

Question 13

Elimination of Macrolides and ketolides :

Answer 13

Elemination occurs via hepatic Metabolism
- Metabolites of both erythromycin and ezithromycin appear in bile
-Metabolites of Clarithromycin appear in the urine

Question 14

Drug- drug interaction of Macrolides and ketolides :

Answer 14

They inhibit hepatic metabolism of a number of drugs including warfarin , by inhibiting CYP450 system
بالتالي ممنوع الماكرو والكيتو يتاخدوا مع ال warfarin لأنه رح يصير bleeding

Question 15

Macrolides and ketolides contraindications:

Answer 15

In patients with hepatic dysfunction

Question 16

Adverse effects of Macrolides and ketolides :

Answer 16

1) Gastric distress and Motility ( GI disturbance )
2) ototoxicity
3)hepatotoxicity
4) Jaundice

Question 17

Gastric Motility and ERYHTHROMYCIN :

Answer 17

High dose of erythromycin can cause smooth muscle contraction and bowl movement which is helpful to a limited distinct

Question 18

Fidaxomicin and Macrolides

Answer 18

They are structurally similar but with different MOA

Question 19

MOA of Fidaxomicin :

Answer 19

It acts on the sigma subunit of RNA polymerase causing disruption of bacterial transcription thus blocking Protein synthesis.

Question 20

Antibacterial spectrum of Fidaxomicin :

Answer 20

Gram-positive bacteria aerobes and anaerobes

Question 21

Clinical Spectrum of Fidaxomicin :

Answer 21

Clostridium difficle infections

Question 22

Absorption of Fidaxomicin:

Answer 22

They are poorly absorbed , remains in GI

Question 23

Adverse effects of Fidaxomicin :

Answer 23

Nausea, Vomitting and abdominal pain

Question 24

About Fidaxomicin:

Answer 24

They can rarely cause cross-resistance with other anti-biotics.
They can cause cross allergy

Question 25

MOA of Chloramphenicol :

Answer 25

Binds reversibly to the 50S subunit of bacterial ribosome and then inhibit peptidyl transferase reaction

Question 26

Antibacterial Spectrum of Chloramphenicol:

Answer 26

1) Broad-Spectrum antibiotic 2) Mainly bacteriostatic but can be bactericidal depending on the dose and the organism

Question 27

Clinical aspect of chloramphenicol:

Answer 27

Limited use due to high toxicity

Question 28

Route of administration for chloramphenicol:

Answer 28

It is given IV

Question 29

Elemination of chloramphenicol:

Answer 29

Can be Elemination in breast milk

Question 30

Chloramphenicol Contraindications :

Answer 30

Breastfeeding Mother

Question 31

Adverse effects of Chloramphenicol:

Answer 31

1) Anaemias 2) Gray baby Syndrome 3) Drug-drug interaction

Question 32

Types of anaemia caused by chloramphenicol:

Answer 32

1) Aplastic anaemia 2) Haemolytic Anaemia

Question 33

What happens in gray baby syndrome triggered by chloramphenicol is that :

Answer 33

Chloramphenicol accumulation occurs due to undeveloped liver/kidney functions which can cause cell death

Question 34

Drug-drug interaction on chloramphenicol:

Answer 34

It can not be taken with warfarin for example because it inhibits liver metabolic functions

Question 35

MOA of clindamycin :

Answer 35

Same as erythromycin

Question 36

Anti-bacterial Spectrum of Clindamycin :

Answer 36

Effective against gram-positive bacteria including MRSA and Staphylococcus

Question 37

Route of administration of Clindamycin :

Answer 37

Oral and IV

Question 38

Adverse effects of Clindamycin:

Answer 38

Skin rash and diarrhoea which indicates severe pseudomembranous colitis due to overgrowth of C.difficle which can be treated with vancomycin or metronidazole.