Antibiotics

Question 1

What are antibiotics?

Answer 1

Antibiotics are substance which are produced by microorganism and capable of killing bacteria.
Antibacterial activity can either be bacteriostatic or bactericidal.
Bacteriostatic: stop bacteria cell growth; Bacteriocidial: kill bacteria cell

Question 2

Classes of antibiotics?(8)

Answer 2

Sulfonamides
Beta-lactams
Amino glycosides
Tetracyclines
Chloraphenicol
Microlides
Lincosamide
Quinolones

Question 3

Sulfonamides

E.g Sulfadiazine, Sulfadozine, Sulfaxalazine.

Answer 3

MOA
They work by inhibiting folic acid synthesis which is essential for the synthesis of DNA and RNA. Their activity is bacteriostatic.
Uses
They can be used to treat urinary tract infections, burns.
They can also be used in treatment of malaria but in combination. For instance Trimethoprin + Sulfamethoxazone = Co-trimoxazole

Question 4

Side effects of sulfonamides

Answer 4

Rashes

Fever

Question 5

Beta lactam

E.g Penicillin, Cephalosporins

Answer 5

They all vary in chemical structure and their enzymes are the beta-lactamase and it binds to the ring thereby inhibiting the bacteria effect of this structure

Question 6

Penicillin

Answer 6

MOA
They inhibit the synthesis of bacteria cell wall and their activity is Bacteriocidial. Beta-lactamase enzymes inactivate this class of antibiotics leading to resistance.

Question 7

Classifications of Penicillin

Answer 7

1.Natural penicillin
E.g Penicillin G, Penicillin V
The major difference between Penicillin G and V is their absorption in the GIT, penicillin G have poor absorption in the GIT so it is best absorbed intravenously unlike penicillin V which is absorbed well in the GIT.
They can be used to treat a wide bacterial infection such as meningitis, streptococcus, staphylococcus.

Question 8

Classifications of Penicillin cont’d

Answer 8

Antistaphylococcus penicillin (beta-lactamase resistance penicillin)
E.g Meticillin, Temocillin
Broad spectrum penicillin
E.g Amoxicillin and Ampicillin

Question 9

NOTE

Answer 9

Amoxicillin and Clavulanic acid combination is one of the most effective penicillin called Augmetin.
Clavulanic acid in amoxicillin inhibits beta-lactamase enzyme so as to reduce resistance.
Augmetin can be administered parentally or orally.

Question 10

Uses and Side effects of Penicillin

Answer 10

It is used to treat gonorrhea (amoxicillin) , and syphilis (penicillin G). It is also used to treat urinary tract infections, pneumonia.
Side effects
Rashes
Fever
GIT disturbance

Question 11

What are Cephalosporins and their different generations?

Answer 11

They have the same MOA as beta-lactams which is the inhibition of bacteria cell wall synthesis and beta-lactamase enzyme binds to the ring thus causing resistance.
They are classified into 3 generations.

Question 12

The generations of Cephalosporins?

Answer 12

First generation
Cefradine, Cefalexin. They are no longer in use.
Second generation
Cefuroxime, Cefaclor
Third generation
Cefixime. They have poor oral absorption.

Question 13

Amino Glycosides

E.g Gentamicin, Streptomycin, Neomycin.

Answer 13

MOA
They inhibit bacteria-protein synthesis. Their effects is Bacteriocidial. They are not administered orally but can only be given IV or IM lly.

Question 14

Tetracyclins

E.g Tetracyclines, Doxycycline

Answer 14

They have the same MOA as amino glycosides i.e they inhibit bacteria-protein synthesis. But their activities is bacteriostatic because tetracyclines chillate metal ions and forms non-absorbable complex.
Milk and certain antacids should be avoided during administration.

Question 15

Uses of tetracyclins and their side effects

Answer 15

They are used to treat Chlamydia infections, respiratory tract infections.

Side effects
GIT disturbances

Question 16

Chloraphenicol

Answer 16

MOA
They inhibit bacteria-protein synthesis but their activities are bacteriostatic.
Uses
They are used topically to treat bacteria eye infection .

Question 17

Microlides

E.g Erythromycin, Clarithromycin

Answer 17

MOA
They inhibit bacteria-protein synthesis but they are both bacteriostatic and Bacteriocidial in their activities.
They can be given orally and IV lly.