Sulfonamides Flashcards Preview

Pharmacology > Sulfonamides > Flashcards

Flashcards in Sulfonamides Deck (14):
1

What is the basic mechanism of a sulfonamide?

Inhibit dihydropteroate synthetase (inhibit PABA incorporation into dihydropteroic acid)

2

Sulfonamides alone are bacteri_____

Bacteriostatic

3

Trimethoprim basic mechanism

Inhibits dihydropteroate reductase (inhibit purine formation)

4

Trimethorpim alone is bacteri_____

Bacteriostatic

5

Trimethoprim-Sulfamethoxazole is bacteri_____. How does the combination affect resistance and spectrum of activity?

Bactericidal

Decreases resistance
Broadens spectrum of activity

6

Sulfonamides
Mechanisms of Resistance

Make lots of PABA
Structural change to dihydropteroate synthetase
Make drug resistant enzyme
Decreased permeability to sulfonamides

7

Trimethoprim
Mechanisms of Resistance

Production of resistant dihydropteroate reductase enzyme
Change cell permeability

8

TMP-SMX Spectrum of Activity

Gram positives
Staph aureus (including some MRSA and CA-MRSA)
Strep pyogenes
Nocardia
Listeria monocytogenes

Pneumocystis carinii

Gram Negatives
Stenotrophomonas maltophilia
Acinetobacter
Enterobacter
E coli
Klebsiella
Proteus
Salmonella, Shigella

9

TMP-SMX Absorption

IV or PO. Rapidly and completely absorbed

10

TMP-SMX Distribution

Good distirbution to urine, lungs, prostate, CSF

11

TMP-SMX Elimination

Eliminated by kidney and liver. Adjust dose in renal insufficiency

12

TMP-SMX Clinical Uses

Acute, chronic, recurrent UTIs
Bacterial prostatitis
Skin infections from CA-MRSA
Norcardia
Pneumocystis carinii
Stenotrophomonas maltophilia

13

TMP-SMX Adverse Effects

Nausea, vomiting
Leukopenia, thrombocytopenia
Rash
Crystalluria

14

TMP-SMX Drug Interactions

Phenytoin (increase phenytoin levels)
Warfarin (increased anticoagulability)
Methotrexate (decrease renal clearance)

Decks in Pharmacology Class (67):