Sulfonamides Flashcards
What do Sulfs do?
They work as PABA agonists to interfere in the synthesis of FA
4 characteristics of Sulfs
weak organic acid
wide pKA range
STATIC
synthetic
SHORT ACTING TID (5)
SulFACEtamide *ophthalmic SulFAMEthizole SulFATHiozole SulfiSOXazole *UTI SulfaCHLORpyridazine *resp/enteric/great for newborns
SHORT ACTING SUMMARY
FACE FAME FATH SOX CHLOR
INTERMEDIATE BID (4)
SulfameTHOXAzole (co-trimoxazole) UTI small animals
SulFAPYridine
SulfameTHAZINE/SulFADimidinefeedadditives+prophylactic
SulfaDIAzine
INTERMEDIATE SUMMARY
THOXA
FAPY
THAZINE/FAD
DIA
LONG LASTING SID (3)
SulfaDIMEthoxine
SulfameTHAZINE *intermediate as well! zeeeeeen
SulfaMETHOXYpyridazine
LONG LASTING SUMMARY
DIME
THAZINE *Intermediate as well!
METHOXY
Enteric Sulfs FEATURE
decreased solubility with limited absorption
ENTERIC SULFS (5)
Succinylsulfathiozole Sulfasalazine *colitis in dogs Sulfaquinoxaline *coccidiosis Sulfaguanidine Phthalylsulfathiazole
TOPICAL SULFS
Silver sulfadiazine
Maferide
(Great absorption)
OPHTHALMIC
Sulfacetamide
SULFS ACT ON AND DON’T ACT ON
GRAM +/- (EXCEPT P.A)
AEROBIC
PROTOZOAS
DON’T WORK ON OBLIGATED ANAEROBIC/NECROTIC TISSUE
PHARM.KINETICS
Oral vs Parenteral
Oral: Great absorption but decreased absorption with enteric ones delayed absorption in ruminants
Parenteral: IM and SQ with buffered solution to prevent extravasation. Well absorbed
Distribution
Wide
Gets in all the fluids but in milk, low concentration so not good for treating mastitis.
Distribution depends on…
pKa and protein binding
Metabolism
Major: Acetylation in liver and lungs
DOGS!!! Glucorinide conjugation and aromatic hydroxylation to make it water soluble
Does acetylation yield water soluble metabolites like Glu and aromatic hydroxylation?
NO. so these less soluble metabolites settle in renal tubules= CRYSTALLURIA
HOW to deal with crystalluria?
increase water intake to increase urine pH to ionize the drug so that it can leave the body
Excretion via
Kidneys
1) glom filtration
2) tubular secretion
3) tubular reabsorption if acidic urine pH
How do long acting sulfs get excreted?
enterohepatic recycling
tubular reabsorption
