MCQs ON  Penicillin & cephalosporin Pharmacology:49

MCQs ON  Penicillin & cephalosporin Pharmacology

1. First drug of choice in gonorrhea is:

a) Cephalosporin

b) sulphonamide

c) penicillin

d) sulfone

2. Penicillin was accidently discovered in:

a) 1922

b)1924

c)1921

d)1928

3. The cephalosporin most resistant to staphylococcus beta lactamase is:

a) cefalothin

b) cefoxitin

c) cefotaxime

d) ceftriaxone

4. Which statement of the following statement are true regarding cefepime?

a) it is a 4th generation cephalosporin

b) once day dose is sufficient

c) it has no antipseudomonal activity

d) it is a prodrug.

5. What reaction is catalysed by a betalactamase enzyme

a) the final crosslinking reaction to form the bacterial cell wall

b) The hydrolysis of the acyl side chain from penicillin structure.

c) the hydrolysis of the four membered ring present in penicillins.

d) the biosynthesis of the penicillin structure from the amino acids valine and 

cysteine.

6. The antimicrobial activity of penicillin is due to?

a) Thiazolidine ring

b) Betalactam ring

c) oxazolidine ring

d) None

7. MOA of cephalosporin involves:

a) Inhibition of beta lactamase

b) inhibition of peptide synthesis

c) inhibition of transpeptidase enzyme

d) interfere with synthesis of cytoplasmic membrane

8. Which of the following is most nephrotoxic cephalosporin ?

a) Cephaloridine

b) cephalothin

c) cefoperazone

d) gentamycin

9. The penicillin G preparation with the longest duration of action:

a) Sodium penicillin

b) ampicillin

c) benzathine penicillin

d) procaine penicillin

10. Not a semisynthetic penicillin?

a) penicillin

b) penicillin G

c) Methicillin

d) Amoxicillin

11. which one of the following statement about ampicillin is false:

a) its activity is enhanced by sulbactam

b) it causes maculopapular rashes

c) it is the drug of choice for Listeria monocytogenes infection

d) it eradicates most stains of MRSA

12. Select the 3rd generation cephalosporin among the following:

a)Cefuroxime

b) cefotetan

c) cefaclor

d) ceftibuten

13. The action of penicillin requires the presence of cell wall that contains:

a) proteoglycans

b) peptidoglycans

c) N-acetyl glucosamide

d) N-acetyl muramic acid

14. The most frequent side effects of bacampicillin is:

a) nausea and vomiting

b) loose motions

c) constipation

d)nephropathy

15. The most important reason for highly restricted use of penicillin G injections in 

present day therapeutics is its:

a) Narrow spectrum of activity

b) Potential to causes hypersensitivity reaction

c) short duration of action

d) neurotoxocity

16. Which of the following statement is true regarding the properties of 

benzylpenicillin.

a) It is a bacteriostatic agent

b) it is active over a wide range of bacterial species

c) it is resistant to beta lactamase

d) certain individuals may have an allergic response to it.

17. The beta lactam antibiotic causes interstitial nephritis is:

a) methicillin

b) ampicillin

c) dicloxacillin

d)nafcillin

18. Which of following is acid labile but not penicillinase susceptible:

a) Dicloxacillin

b) penicillin G

c) methicillin

d) cloxacillin

19. DOC for VRSA:

a) Ceftriaxone

b) piperacillin+ Tazobactam

c)linezolid

d)amipicillin+ Clavulanic acid

20. Following ADR is not seen with cephalosporin:

a) Bleeding

b) disulfiram rxn

c) teratogenicity

d) None

Answer key : 

1.a 

2. d 

3.a 

4.a 

5.c 

6.b 

7.c 

8.a 

9.c 

10.b 

11.d 

12.d 

13.b 

14.b 

15.b 

16.d 

17.a 

18.c 

19.c 

20.c

What is the first-choice drug for gonorrhea?

The first-line treatment for gonorrhea is cephalosporin, specifically Ceftriaxone (a third-generation cephalosporin), due to its high efficacy against Neisseria gonorrhoeae.

Who discovered penicillin, and when?

Alexander Fleming accidentally discovered penicillin in 1928, revolutionizing the treatment of bacterial infections.

What is the mechanism of action of cephalosporins?

Cephalosporins inhibit the transpeptidase enzyme, preventing bacterial cell wall synthesis and leading to bacterial death.

Why is penicillin G not used orally?

Penicillin G is acid-labile, meaning it gets destroyed by stomach acid, making it ineffective when taken orally.

What is beta-lactamase, and how does it affect antibiotics?

Beta-lactamase is an enzyme produced by some bacteria that breaks the beta-lactam ring of penicillins and cephalosporins, rendering them ineffective.

Why is methicillin no longer widely used?

Methicillin was withdrawn from clinical use due to its high nephrotoxicity (causing interstitial nephritis).

What is the longest-acting penicillin?

Benzathine penicillin has the longest duration of action, making it useful for long-term prophylaxis (e.g., in rheumatic fever).

What is the major side effect of penicillins?

Penicillins can cause hypersensitivity reactions, ranging from mild rashes to anaphylaxis, which can be life-threatening.

What is the main reason for restricted use of penicillin G today?

Penicillin G is narrow-spectrum and has a high potential for allergic reactions, limiting its widespread use.

What is the mechanism of beta-lactamase inhibitors like clavulanic acid?

Beta-lactamase inhibitors, such as clavulanic acid, sulbactam, and tazobactam, work by inhibiting beta-lactamase enzymes, restoring the activity of beta-lactam antibiotics.

What is the drug of choice for MRSA (Methicillin-resistant Staphylococcus aureus)?

Vancomycin is the first-line treatment for MRSA, but linezolid is also used for resistant cases.

What is the drug of choice for VRSA (Vancomycin-resistant Staphylococcus aureus)?

Linezolid is the preferred drug for treating VRSA infections.

Why do cephalosporins sometimes cause bleeding?

Some cephalosporins (e.g., Cefotetan, Cefoperazone) can interfere with vitamin K metabolism, leading to an increased risk of bleeding.

Which cephalosporin has the highest nephrotoxicity?

Cephaloridine is the most nephrotoxic cephalosporin.

What are the major adverse effects of cephalosporins?

Bleeding tendency, disulfiram-like reaction (with alcohol), hypersensitivity reactions, and nephrotoxicity.

Which penicillins are resistant to beta-lactamase?

Methicillin, Nafcillin, Oxacillin, and Dicloxacillin are beta-lactamase resistant and are used against penicillinase-producing Staphylococcus aureus.

Which cephalosporins cover Pseudomonas aeruginosa?

Ceftazidime (3rd gen) and Cefepime (4th gen) are effective against Pseudomonas aeruginosa.

Why are cephalosporins preferred over penicillins in some infections?

Cephalosporins have a broader spectrum of activity, better resistance to beta-lactamase, and cause fewer hypersensitivity reactions compared to penicillins.

Which penicillins are used for Listeria monocytogenes infections?

Ampicillin is the drug of choice for Listeria monocytogenes infections.

Can cephalosporins be used in penicillin-allergic patients?

Patients with mild penicillin allergy may tolerate cephalosporins. However, those with severe reactions (e.g., anaphylaxis) should avoid cephalosporins due to cross-reactivity.