Sulfonamides, UTI Agents

Question 1

Sulfonamides include:

Answer 1

Sulfamethoxazole (one component of Bactrim)

Sulfadiazepine

Question 2

What are the indications for sulfonamides?

Answer 2

Otitis media 
Meningitis 
UTI's 
Toxoplasmosis (sulfadiazepine)
PCP (sulfadiazepine)
URI's
Stenotrophomonas maltophilia 
(Bactrim can treat all)

Question 3

The action of sulfonamides is (static/cidal)?

Answer 3

Bacteriostatic (inhibits growth)

Question 4

MOA of sulfonamides:

Answer 4

Mimics PABA and inhibits bacterial biosynthesis of folic acid

Question 5

AE of sulfonamides:

Answer 5

Hypersensitivity
Hemolytic anemia
Megaloblastic anemia (d/t effect on folic acid)
Neutropenia
Agranulocytosis
Crystalluria/hematuria (drink lots of fluids)
Photosensitivity

Question 6

DI with sulfonamides include:

Answer 6

PABA containing compounds (ex-procaine)
Bactrim inhibits CYP2C9
=potentiat effects of warfarin, sulfonylureas, phenytoin

Question 7

Cross-sensitivity with other sulfonamides include:

Answer 7

Thiazides
Furosemide
Sulfonylureas
Sulfones

Question 8

What are the two components of Bactrim?

Answer 8

Sulfamethoxazole and Trimethoprim

Question 9

What is Trimethoprim’s MOA by itself and when combined with sulfamethoxazole?

Answer 9

Inhibits dihydrofolate reductase decreasing folic acid synthesis by itself
With sulfamethoxazole= synergistic effect of folic acid, decreases resistance

Question 10

When is trimethoprim used by itself?

Answer 10

In patients with sulfonamide allergies

Question 11

What sulfone is the drug of choice for leprosy?

Answer 11

Dapsone

Question 12

Why is Dapsone less used than sulfamethoxazole?

Answer 12

More toxic
AE: hemoyltic anemia, leukopenia, methemoblobinemia, anorexia, N/V, HA, dizziness, nervousness, lethargy, psychosis, mononucleosis-like syndrome (potentially lethal)

Question 13

What lab value needs to be checked when prescribing Dapsone and why?

Answer 13

G6PD levels

If patients are deficient in this enzyme they can be at a higher risk of developing hemolytic anemia

Question 14

Dapsone can be useful in the prophylaxis of what?

Answer 14

PCP (tx of this too)

Toxoplasmosis

Question 15

What drug is used in the treatment of UTIs but provides no antibacterial activity and why is it used?

Answer 15

Phenazopyridine (Pyridium)

Provides local anesthetic action in the urinary tract

Question 16

What common SE should patients be counseled about when using Phenazopyridine?

Answer 16

Discolaration

Question 17

What bacteria associated with a UTI is Nitrofurantoin specifically useful in the treatment of?

Answer 17

E.Coli

Question 18

What is Nitrofurantoin’s MOA?

Answer 18

Inhibits the number of bacterial enzymes necessary for protein, DNA, RNA, and cell wall synthesis

Question 19

Why is Nitrofurantoin specific to the treatment of UTI’s?

Answer 19

Heavily concentrated in the urine. When at therapeutic concentrations in the urine it is bacterioCIDAL

Question 20

AE of Nitrofurantoin include:

Answer 20

GI distress, HSR, HA, vertigo, dizziness, polyneuropathy (high doses), dark orange-brown urine

Question 21

When would you not use Nitrofurantion?

Answer 21

If a patient’s Cr Clearance was <60= increased risk for polyneuropathy

Question 22

What is the difference between the available forms of NItrofurantoin, Macrodantin vs. Macrobid?

Answer 22

Macrobid is longer acting and can be dosed 2x/day while Macrodantin needs to be dose 4x/day

Question 23

Can Nitrofurantoin be given in pregnancy?

Answer 23

Yes, but not close to delivery d/t decreased enzyme activity in the newborn that may result in anemia