Pharm - inhibitors of bacterial protein synthesis

Question 0

What drugs bind to the “P” site?

Answer 0

Aminoglycosides

Question 1

What is the initiating amino acid in bacterial protein synthesis that starts the process of translation?

Answer 1

Formyl - methionin

Question 2

What drugs bind to the “A” site?

Answer 2

Tetracyclines

Question 3

What drugs inhibit peptidyl transferase?

Answer 3

Chloramphenicol

Question 4

What drugs inhibit translocation of the ribosomes by binding to the 50S subunit?

Answer 4

Macrolides and Clindomycin

Question 5

What group of bacteria are resistant to aminoglycosides?

Answer 5

Anaerobes, because aminoglycosides are accumulated intracellularly by an Oxygen-dependent process.

Question 6

Primary side effect of aminoglycosides?

Answer 6

Nephrotoxicity. Due to it being a sugar - water soluble - polar - thereby eliminated via kidneys.

Question 7

aminoglycoside causing contact dermatitis?

Answer 7

Neomycin

Question 8

Resistance to aminoglycosides are aquired by bugs that can produce ………..

Answer 8

Resistance to aminoglycosides are aquired by bugs that can produce conjugating enzymes that increase the elimination rate of the drug.

Question 9

Tetracyclines mecganism of action?

Answer 9

inhibit elongation by binding to the 30S subunit and preventing the tRNA from binding to the A site

Question 10

doxycycline, minocycline and demeclocycline are all …………. antibiotics

Answer 10

doxycycline, minocycline and demeclocycline are all Tetracycline antibiotics

Question 11

Why do Tetracyclines lower bone growth and cause tooth enamel dysplasia?

Answer 11

It is a chelating agent. It binds to Calcium and lower bone density..

Question 12

Any substance that has …phen… in its name is ………

Answer 12

Any substance that has …phen… in its name is lipid soluble.

Question 13

Any drug that has “phen” in its name is ………….. and therefore excreted by …………. which indicates possible ………………

Answer 13

Any drug that has “phen” in its name is lipid soluble and therefore excreted by the liver(bile) which indicates possible liver toxicity

Question 14

Chloramphenicol general picture?

Answer 14

Bacteriostatic wide spectrum antibiotic
Lipid soluble, good tissue distribution.
Glucuronidation; dose reduction are needed in liver dysfunction.
General inhibitor of cytochrome P450

Question 15

Anything with the “..thromycin” suffix means that it is ………..

Answer 15

Anything with the “..thromycin” suffix means that it is a macrolide

Question 16

Macrolides general picture?

Answer 16

Gram positive cocci
atypical organisms(mycoplasma, mycobacterium, ureaplasma)
side effects: stimulate motilin receptors(GI distress) and reversible deafness

Question 17

Clindamycin general picture?

Answer 17

• NOT a macrolide but has same moa.
• Particularily good against S. aureus.
• side effect: pseudomembranous colitis

Question 18

Linezolid general picture?

Answer 18

• inhibits formation of initiation complex by binding 50S subunit.
• treatment of VRSA and VRE
• side effects: bone marrow suppression

Question 19

Aminoglycoside moa?

Answer 19

binds to 30S subunit and “freeze” initiation complex

Question 20

aminoglycosides bacteriocidal or bacteriostatic?

Answer 20

Bacteriostatic for the most part. Bacteriocidal to some gram negs.

Question 21

Aminoglycosides route of entry into bacteria?

Answer 21

Porin channels

Question 22

Aminoglycosides CNS involvement?

Answer 22

do NOT penetrate CNS

Question 23

Streptomycin area of use?

Answer 23

Yersinia pestis - plague

Question 24

Aminoglycosides coadministration?

Answer 24

Beta-lactams + vancomycin

Question 25

Aminoglycosides and ototoxicity?

Answer 25

Vestibular: streptomycin, gentamycin, tobamycin
Cochlear: neomycin, kanamycin, amikacin

Question 26

aminoglycosides adverse effects?

Answer 26

• nephrotoxicity(acute tubular necrosis)
• ototoxivity
• rarely cause hypersensitivity reactions

Question 27

Tetracyclines mechanism of action?

Answer 27

binds with 30S subunit and “crowds out” aminoacyl tRNA from mRNA complex

Question 28

Tetracyclines primary route of elimination?

Answer 28

kidneys! Except for doxycycline, which is eliminated in bile.

Question 29

3 cool uses of tetracyclines?

Answer 29

• borreliosis
• H. pylori
• Cholera

Question 30

Tetracyclines adverse effects?

Answer 30

• Hepatic damage(esp. in pregnant ladies)
• tooth colourations
• retarded bone growth in neonates

Question 31

Chloramphenicol moa?

Answer 31

binds to 50S subunit and block peptidyl transferase - thus preventing amino acid incorporation and elongation of peptide chain

Question 32

Chloramphenicol pharmacokinetics?

Answer 32

• rapid absorption
• inactive prodrug is hydrolyzed by plasma esterases = active drug
• inhibits CYP P450

Question 33

Chloramphenicol target organisms?

Answer 33

• gram negs

- anaerobes such as clostridium, chlamydia, mycoplasma

Question 34

Chloramphenicol adverse effects?

Answer 34

• bone marrow suppression
• hemolytic anemia in G6PD
• grey baby syndrome(low P450 and conjugation presents like shock

Question 35

Erythromycin general picture?

Answer 35

• macrolide ab that binds and inhibit 50S amino acyl translocation
• enteric coated tablet to protect from gastric environment
• distributed in all body fluids, NOT CNS.

Question 36

Erythromycin target organisms?

Answer 36

• gram positives
• legionnaires disease
• bordetella pertussis
• syphillis

Question 37

Erythromycin adverse effects?

Answer 37

• GI disturbances
• inhibit P450 metabolism of Warfarin and Phenytoin
• allergic cholestatic hepatitis

Question 38

Clindamycin general picture?

Answer 38

like erythromycin… which would be?

Question 39

Clindamycin adverse effects?

Answer 39

• produce diarrhea in 20% of patients

- pseudomembranous colitis

Question 40

Clindamycin area of use?

Answer 40

• prophylaxis against B.fragilis(surgery)
• endocarditis
• topical treatment of acne