ORG: Sulfonamides Flashcards
Domagk discovered this dye with antibacterial properties
Prontosil dye
First synthetic antibacterial agent acting on wide range of infections
Sulfanilamide
First sulfonamide synthesized to combat pneumonia
Sulfapyridine
Precursors of dihydrofolic acid
PABA
Glutamate
Pteridine
MOA of Sulfonamides
Act as synthetic analogue of PABA and compete with substrate Dihydropteroate synthetase
Old name of folic acid
Pteroyl-glutamic acid
Spectrum of activity of sulfonamides
All gram (+) Cocci All gram (+) Bacilli Nearly all gram (-) cocci and enterobacteriaceae Malaria Nocardia
Preferred drug for acute toxoplasmosis
Sulfadiazine + Pyrimethamine
Given to patients undergoing sulfonamide treatment to prevent bone marrow suppression
Folinic acid
Organism resistant to one sulfonamide is resistant to all (T/F)
True
Resistance to sulfonamides may be due to:
- ) Increase PABA production
- ) Altered dihyropteroate synthetase
- ) Reduced permeability to sulfonamides
Site of absorption (Sulfonamides)
Small intestine
Absorption is increased for sulfonamides when what part of molecule is free
Para-amino group
Indication: Sulfasalazine
Chron’s Disease or Ulcerative Colitis
Ind: Pthalylsulfacetamide
Ulcerative colitis
Sulfasalazine is split by local intestinal flora to
- ) Sulfapyridine
2. ) 5-aminosalicylate
Sulfonamides are not usually applied topically. Why?
Sensitization
Silver sulfadiazine is preferred over mafenide. Why?
Mafenide produces pain on application
S/E of Mefenide acetate
Absorbed thru burns thus causing acid base imbalance
Sulfonamide distribution is through
Binding with serum albumin
Sulfonamides cannot penetrate the CSF. (T/F)
False. They can penetrate the CSF, placental barrier and enter fetal tissues
Metabolism of sulfonamide
N-Acetylation
Excretion of sulfonamides
Glomerular filtration. May also be excreted in breast milk
Adverse effects of sulfonamides
Crystalluria, Hypersensitivity reactions, Kernicterus, Hemopoietic disturbances, Drug potentiation
Mgt of crystalluria caused by sulfonamides
Adequate hydration and alkalinization of urine with sodium bicarbonate
S/E commonly encountered in long acting sulfonamide
Rashes
Hypersensitivity reactions have higher incidence with what sulfonamide drug
Sulfapyridine
Hemolytic anemia is a side effect of sulfonamide when given to newborns with what condition
G6PD
Kernicterus is observed in sulfonamide treatment. Why?
Displacement of bilirubin from serum albumin
Sulfonamide potentiates warfarin and methotrexate. Why?
Displacement from serum albumin
Contraindications of sulfonamides
Newborns
Infants less than 2 months
Pregnant women at term
Drug contraindicated with sulfonamides
Methenamine
Why is sulfonamide contraindicated with methenamine
Sulfonamide condenses with formaldehyde
Sulfonamides are given with what drugs, in the treatment of otitis media
Penicillins or Erythromycin
Sulfonamides are given during meningococcal infections, but what is the DOC
Pen G
Sulfonamide used for trachoma infections and inclusion conjunctivites
Sulfacetamide
Sulfonamides are generally incompatible with
Acidic drugs and precipitable amines.
Sulfacetamide is given with what drugs, for vaginitis caused by Haemophilus vaginalis
Sulfabenzamide and Sulfathiazole
Sulfonamide of choice for CNS Infections
Sulfadiazine
Sulfonamide for chloroquine resistant Falciparum malaria
Sulfadoxine + Pyrimethamine
Most used sulfonamide
Sulfamethoxazole
Sulfonamide best suited for treatment of UTIs
Sulfamethoxazole
Treatment or prophylaxis of choice for Pneumonitis caused by P.carinii and Enterocolitis by Isospora
Co-trimoxazole
