penicillins

Question 1

penicillin g spectrum

Answer 1

1- g+ cocci - streptococci + pneumococci + staphylococci
2- g- cocci - meningococci + gonococci
3- b+ - bacillus anthracis + clostridia + Corynebacterium diphtheria
4- spirochetes - treponema pallidum + fusospirochete
5- miscellaneous - listeria monocytogenes + actinomycis Israeli + pastruella multocida

Question 2

penicillin g therapeutic uses

Answer 2

1- acute tonsillitis + streptococcal arthritis + acute pharyngitis + streptococcal pneumonia + skin rashes
2- staphylococcal infections
3- P. pneumonia + P. meningitis + M.meningitis
4- anaerobic infections
5- gonorrhea
6- anthrax + tetanus and gas gangrene + diphtheria
7- syphillus
8- leptoserosis + actinomycosis

Question 3

erratic absorption

Answer 3

nafcillin

Question 4

half life

Answer 4

30 mins - 1 hr

Question 5

IV

Answer 5

1- penicillin g
2- ampicillin
3- piperacillin
4- ticarcillin

Question 6

IM

repository penicillin g inj.

Answer 6

procaine + benzathine

Question 7

with food administration

Answer 7

amoxicillin

Question 8

acid stable

Answer 8

dicloxacillin + ampicillin + amoxicillin

Question 9

excretion

Answer 9

mostly by urine

10% glomerular + 90% tubular

Question 10

tubular secretion inhibited

Answer 10

probenecid

Question 11

biliary excretion

Answer 11

nafcillin + ampicillin

Question 12

biliary + urinary excretion

Answer 12

oxacillin

Question 13

secreted in

Answer 13

sputum
breast milk
can cross inflamed meninges

Question 14

resistance

Answer 14

1- Inactivation of antibiotic by β-lactamase (most common)
2- Modification of target PBPs
3- Impaired penetration of drug to target PBPs
4- Antibiotic efflux

Question 15

MOA

Answer 15

1- penicillin —— bind and inactivate PBPs on susceptible bacteria———— inhibit transpeptidase —————— prevent peptidoglycan synthesis ————— cell wall deficients form-spheroplast and filamentous forms ————– autolysis ————- cell death (bacteriocidal)
2- activate autolysins - destroy already built cell wall
3- delay lysis

Question 16

poor penetration in

Answer 16

eye
prostate
cns

Question 17

penicillin v

Answer 17

acid stable compared to pen. g

Question 18

bioavailability (v)

Answer 18

poor

Question 19

narrow antibacterial spectrum (v)

Answer 19

less active against Neisseria + anaerobes

Question 20

benzathine pen. g

Answer 20

prophylaxis of rheumatic fever

1. 2 MU/month every 4weeks till 18 yrs OR 5 yrs after attack
2. 4 MU once a week + 1-3 weeks - treatment of SYPHILIS

Question 21

procaine pen. g

Answer 21

rarely used

due to resistant strains

Question 22

two rings

Answer 22

thiozide

b-lactam