Semi Synthethic Penicillin

Question 0

Penicillin V ( phenoxy methyl penicillin)
Route of administration
Antimicrobial spectrum
Uses

Answer 0

Oral
Microbes spectrum similar to penicillin G, but it has low plasma concentration -
✳ Mild streptococcus infections
✳ Mild pneumococcal infections

Question 1

Classify the semi synthetic penicillin

Answer 1

ACID RESISTANT PENICILLIN
Penicillin V

PENICILLINASE RESISTANT PENICILLIN 
Methicillin
Cloxacillin
Oxacillin
Dicloxacillin

EXTENDED SPECTRUM PENICILLIN
Aminopenicllin
- Ampicillin
- Amoxicillin

Carboxypenicillin

• Carbenicillin
• Carbenicillin indanyl

Ureidopenicillin

• Mezlocillin
• Piperacillin

Question 2

PENICILLINASE RESISTANT PENICILLIN
Route of administration
Antimicrobial spectrum
Uses

Answer 2

Methicillin - IV/IM
C,O,D - oral and parenteral
Staphylococcus aureus and staphylococcus epidermidis
✳ Penicillinase producing staphylococci
✳Staphylococci skin infection ( abcess, cellulitis)
✳Staphylococci pneumonia ( secondary to viral infection)
✳ Staphylococci osteomyelitis

Question 3

AMINOPENICILLIN
Route of administration
Antimicrobial spectrum
Uses

Answer 3

Ampicillin
Amoxicillin ( best ) 
Oral, IV, IM
Cocci - gram positive & negative 
Bacilli - gram positive & NEGATIVE 
Main action on streptococcus pneumoniae
✳Upper respiratory tract infection by Str.pyogenes, Str.pneumoniae, H.influenzae - pharyngitis, otitis media, sinusitis, acute exacebation of chronic bronchitis 

✳ UTI by gram negative bacilli and enterococcus.

✳Meningitis - Listeria monocytogenes ( gram +ve bacilli).
Also empirical therapy with Vancomycin and 3G cephalosporins for Str.pneumoniae, H.Influenza, N.meningitidis.

✳SABE - subacute bacterial endocarditis.
Ampicillin + gentamicin

✳Thypoid carrier eradication with ampicillin

Question 4

CARBOXYPENICILLIN
Route of administration
Antimicrobial spectrum
Uses

Answer 4

Carbenicillin (IV/IM)
Carbenicillin Indanyl (oral)
Effective against Pseudomonas Aeruginosa & Proteus
✳UTI

Question 5

UREIDOPENICILLIN
Route of administration
Antimicrobial spectrum
Uses

Answer 5

Mezlocillin (IM/IV) 
Piperacillin (IM/IV)
Effective against Pseudomonas aeruginosa & Klebsiella 
✳Pneumonia ( VAP & CAM ) 
✳Burns (bluishgreenish pus) 
✳UTI (pseudomonas)

Question 6

Similarities of Aminopenicillins

Answer 6

Both are semi synthetic

Both are acid stable

Question 7

Which has incomplete GIT absorption?

Ampicillin or amoxicillin?

Answer 7

Ampicillin

Question 8

Which of them is not affected by food intake?

Ampicillin or amoxicillin?

Answer 8

Amoxicillin

Question 9

Which is more effective against Shigella and Haemophilus influenza?

Ampicillin or amoxicillin?

Answer 9

Ampicillin

Question 10

Which one reduces effectiveness of OCP?

Ampicillin or amoxicillin?

Answer 10

Ampicillin

Question 11

What is the dosage of aminopenicillins?

Answer 11

Ampicillin
250-500mg q.i.d

Amoxicillin
250-500mg t.i.d