pharmacology of different antibiotics

Question 1

5 ways of harmacological activity

Answer 1

Inhibition of cell wall synthesis
inhibition of protein synthesis
inhibition of nucleic acid synthesis
inhibition of folate synthesis
disruption of cytoplasmic membrane

Question 2

Why gram-negatives are hard to treat?

Answer 2

have a double membrane/wall
variety of defence mechanisms
e.g. change their structure to avoid being targeted

Question 3

which 2 antibiotics are used to combat infections by inhibiting bacterial cell wall synthesis?

Answer 3

Glycopeptides & beta-lactam

Question 4

examples of beta-lactam antibiotics

Answer 4

penicillin
cephalosporins
carbapenem

Question 5

ways for bet-lactam penicillin to be effective?

Answer 5

Penetrate cell layers
keep the beta-lactam ring intact
bind to PBP

Question 6

what does penicillin do in the human body?

Answer 6

inhibit formation of cross-link in the bacterial cell wall

causes weakening of cell wall and cell death

Question 7

what is the mechanism behind the penicillins resitance ?

Answer 7

where bacterium produce beta-lactamase to destroy the beta-lactam ring to disable the molecule

Question 8

examples of penicillin

Answer 8

Benzylpenicillin
phenoxymetylpenicillin (pnicillin V)
amoxicillin
Flucloxacillin
piperacllin
(basially most of them with "cillin" behind)

Question 9

what is the features of Cephalosporins

Answer 9

contain beta-lactam ring
broad spectrium
bactericidal
categorised into generation depending on the amount of gram negative

Question 10

state the generations of cephalospsprin

Answer 10

1st generation
- cefalexin
2nd generation
- cefuroxime, cefaclor
3rd generation
- cefotaxime, ceftriaxone, ceftazidime
4th generation
- broad spectrum
5th generation
- MRSA

Question 11

Describe carbapenems

Answer 11

very broad spectrium of activity
bactricidal
intravenous only
use restricted to prevent resistance
examples:
- ertapenem
- imipenem
- meropenem

Question 12

examples of adverse effects happen in beta lactams

Answer 12

Mild:
-Rash

Severe:

• anaphylaxis
• angioedema –> swelling underneath the skin
• Breathing difficulties
• Stevens-Johnson reaction –> rare disorder of the skin and mucous membranes

Question 13

Describe glycopeptides

Answer 13

excellent activity against gram positive organisms (including MRSA)
they inhibit cell wall synthesis in gram positive ONLY
bactrecdal
intravenous only
narrow therapeutic spectrum
examples: vancomycin & teicoplanin

Question 14

What is the protein synthesis inhibitors that bind to the 50S ribosomal subunit and what do they do?

Answer 14

chloramphenicol, macrolides and linosamides

prevent peptide bond formation
stop protein synthesis

Question 15

What is the protein synthesis inhibitors that bind to the 30S ribosomal subunit and what do they do?

Answer 15

Aminoglycosides
impari proofreading, resulting in production of faulty proteins

Tetracyclines
Block the binding of tRNAs

Question 16

Examples of Tetracycline

Answer 16

oxytetracycline, tetracycline
minocycline, doxycycline
tigecycline

Question 17

examples of aminoglycoside

Answer 17

gentamicin, amikacin, tobramycin

Question 18

examples of macrolide

Answer 18

clarithromycin, erythromycin, azithromycin

Question 19

what is lincosamides and what they do?

Answer 19

interacting witht eh peptidyl transferase site of the 50S ribosomal subunit
good penetration into tissue
good cover against gram positive and anaerobic organisms

Question 20

what is oxazolidinones and what do they do?

Answer 20

protein sythesis inhibitors
bacteriostatic
active against gram positive
inhibits protein synthesis by binding to the P site of the 50S ribosomal subunit

Question 21

How does the inhibition of nitroimidazoles works?

Answer 21

they act by accepting electron under anaerobicconditions

andreactive metabolites interact with DNA & proteins causing cell death

Question 22

what is nitroimidazole use for?

Answer 22

highly active against anaerobic infections and parasitic infections
useful as prophylactic agent in abdominal surgery

examples:
metronidazole, tinidazole

Question 23

How does fluoroquinolones works ?

Answer 23

Directly inhibit DNA synthesis by blocking enzyme DNA gyrase

when binded to DNA gyrase, DNA complex allow broken DNA to be release and leading to cell death

Question 24

what does fluoroquinolone works on?

Answer 24

great activity against gram negative 
absorbed orally
associated with c.difficile infection
examples:
ciprofloxacin, levofloxacin, moxifloxacin