Sulfonamides

Question 1

What does sulfonamide do?

Answer 1

It competes with PABA and inhibits dihydropteroate synthetase in bacteria so this means NO DIHYDROFOLIC ACID.

Question 2

A patient presents to you with complaints of left lumbar pain and nausea. His drug history reveals that he was taking sulfadiazine for a recent infection. What could be the reason for his lumbar pain?

Answer 2

Metabolite of sulphonamides can precipitate in neutral or acidic pH and makes stones. He might have kidney stones.

Question 3

Sulfa drugs are _________(bacteriostatic/bactericidal)

Answer 3

Bacteriostatic

Question 4

What is the combination of drugs used for the treatment of toxoplasmosis?

Answer 4

Sulfadiazine + pyrimethamine

Question 5

What sulfa drug cant be used orally?

Answer 5

Sulfasalazine

Question 6

What is sulfasalazine used for?

Answer 6

Chronic inflammatory bowel disease

Question 7

Can sulfa drugs be used topically?

Answer 7

In burns patients to reduce burn associated sepsis

Question 8

What are the names of topical drugs of sulfonamides

Answer 8

Silver sulfadiazine
Acetate
Mafenide

Question 9

Which is better? Silver sulfadiazine or mafenide

Answer 9

Silver sulfadiazine is better bcz mafenide causes pain and acid base disturbance where it is absorbed

Question 10

In whom toxicity can occur?

Answer 10

Patient who is a slow acetylator
Patients with renal impairment
Patients with hepatic impairment

Question 11

Does sulfonamide cross BBB and placental barrier

Answer 11

Yes

Question 12

How to prevent crystal formation if taking sulfonamide

Answer 12

Maintain adequate hydration and alkalization of urine.

Question 13

What are the hypersensitive reactions if taking sulfa drugs

Answer 13

Angioedema
Rashes
Steven Johnson syndrome

Question 14

What are the hematopoietic side effects of sulfa drugs?

Answer 14

Hemolytic anemia if G6PD DEFICIENCY
Granulocytopenia
Thrombocytopenia

Question 15

If given to a newborn, what does it do?

Answer 15

Kernicterus occurs because sulfa drugs displase bilirubin from serum albumin and bilirubin enters the BBB as its not developed in newborns

Question 16

Sulfa drugs inhibit CYP2C9 so what ither drugs are affected by it?

Answer 16

Warfarin
Phenytoin
Their effects are increased

Question 17

How does sulfa drugs potentiate the effects of warfarin?

Answer 17

Inhibit CYP2C9

Displaces warfarin from albumin

Question 18

Sulfa drugs should not be given to patient receiving ____________ because they can crystallize in the presence of formaldehyde produced by this agent

Answer 18

Methenamine

Question 19

What are the contraindications of Sulfa drugs?

Answer 19

Pregnant ladies
Patients with renal impairement
Patient with hepatic impairement
In lactation
Hypersensitive patients

Question 20

What are drug interactions of sulfonamides?

Answer 20

Oral anticoagulants
Sulfonylurea
Sulfonamide potentiate their effects