Sulfonamides Flashcards
What does sulfonamide do?
It competes with PABA and inhibits dihydropteroate synthetase in bacteria so this means NO DIHYDROFOLIC ACID.
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?
Metabolite of sulphonamides can precipitate in neutral or acidic pH and makes stones. He might have kidney stones.
Sulfa drugs are _________(bacteriostatic/bactericidal)
Bacteriostatic
What is the combination of drugs used for the treatment of toxoplasmosis?
Sulfadiazine + pyrimethamine
What sulfa drug cant be used orally?
Sulfasalazine
What is sulfasalazine used for?
Chronic inflammatory bowel disease
Can sulfa drugs be used topically?
In burns patients to reduce burn associated sepsis
What are the names of topical drugs of sulfonamides
Silver sulfadiazine
Acetate
Mafenide
Which is better? Silver sulfadiazine or mafenide
Silver sulfadiazine is better bcz mafenide causes pain and acid base disturbance where it is absorbed
In whom toxicity can occur?
Patient who is a slow acetylator
Patients with renal impairment
Patients with hepatic impairment
Does sulfonamide cross BBB and placental barrier
Yes
How to prevent crystal formation if taking sulfonamide
Maintain adequate hydration and alkalization of urine.
What are the hypersensitive reactions if taking sulfa drugs
Angioedema
Rashes
Steven Johnson syndrome
What are the hematopoietic side effects of sulfa drugs?
Hemolytic anemia if G6PD DEFICIENCY
Granulocytopenia
Thrombocytopenia
If given to a newborn, what does it do?
Kernicterus occurs because sulfa drugs displase bilirubin from serum albumin and bilirubin enters the BBB as its not developed in newborns
Sulfa drugs inhibit CYP2C9 so what ither drugs are affected by it?
Warfarin
Phenytoin
Their effects are increased
How does sulfa drugs potentiate the effects of warfarin?
Inhibit CYP2C9
Displaces warfarin from albumin
Sulfa drugs should not be given to patient receiving ____________ because they can crystallize in the presence of formaldehyde produced by this agent
Methenamine
What are the contraindications of Sulfa drugs?
Pregnant ladies Patients with renal impairement Patient with hepatic impairement In lactation Hypersensitive patients
What are drug interactions of sulfonamides?
Oral anticoagulants
Sulfonylurea
Sulfonamide potentiate their effects
