Sulfonamides, UTI Agents Flashcards
Sulfonamides include:
Sulfamethoxazole (one component of Bactrim)
Sulfadiazepine
What are the indications for sulfonamides?
Otitis media Meningitis UTI's Toxoplasmosis (sulfadiazepine) PCP (sulfadiazepine) URI's Stenotrophomonas maltophilia (Bactrim can treat all)
The action of sulfonamides is (static/cidal)?
Bacteriostatic (inhibits growth)
MOA of sulfonamides:
Mimics PABA and inhibits bacterial biosynthesis of folic acid
AE of sulfonamides:
Hypersensitivity
Hemolytic anemia
Megaloblastic anemia (d/t effect on folic acid)
Neutropenia
Agranulocytosis
Crystalluria/hematuria (drink lots of fluids)
Photosensitivity
DI with sulfonamides include:
PABA containing compounds (ex-procaine)
Bactrim inhibits CYP2C9
=potentiat effects of warfarin, sulfonylureas, phenytoin
Cross-sensitivity with other sulfonamides include:
Thiazides
Furosemide
Sulfonylureas
Sulfones
What are the two components of Bactrim?
Sulfamethoxazole and Trimethoprim
What is Trimethoprim’s MOA by itself and when combined with sulfamethoxazole?
Inhibits dihydrofolate reductase decreasing folic acid synthesis by itself
With sulfamethoxazole= synergistic effect of folic acid, decreases resistance
When is trimethoprim used by itself?
In patients with sulfonamide allergies
What sulfone is the drug of choice for leprosy?
Dapsone
Why is Dapsone less used than sulfamethoxazole?
More toxic
AE: hemoyltic anemia, leukopenia, methemoblobinemia, anorexia, N/V, HA, dizziness, nervousness, lethargy, psychosis, mononucleosis-like syndrome (potentially lethal)
What lab value needs to be checked when prescribing Dapsone and why?
G6PD levels
If patients are deficient in this enzyme they can be at a higher risk of developing hemolytic anemia
Dapsone can be useful in the prophylaxis of what?
PCP (tx of this too)
Toxoplasmosis
What drug is used in the treatment of UTIs but provides no antibacterial activity and why is it used?
Phenazopyridine (Pyridium)
Provides local anesthetic action in the urinary tract
What common SE should patients be counseled about when using Phenazopyridine?
Discolaration
What bacteria associated with a UTI is Nitrofurantoin specifically useful in the treatment of?
E.Coli
What is Nitrofurantoin’s MOA?
Inhibits the number of bacterial enzymes necessary for protein, DNA, RNA, and cell wall synthesis
Why is Nitrofurantoin specific to the treatment of UTI’s?
Heavily concentrated in the urine. When at therapeutic concentrations in the urine it is bacterioCIDAL
AE of Nitrofurantoin include:
GI distress, HSR, HA, vertigo, dizziness, polyneuropathy (high doses), dark orange-brown urine
When would you not use Nitrofurantion?
If a patient’s Cr Clearance was <60= increased risk for polyneuropathy
What is the difference between the available forms of NItrofurantoin, Macrodantin vs. Macrobid?
Macrobid is longer acting and can be dosed 2x/day while Macrodantin needs to be dose 4x/day
Can Nitrofurantoin be given in pregnancy?
Yes, but not close to delivery d/t decreased enzyme activity in the newborn that may result in anemia
