Sulfonamides Flashcards

1
Q

What is the basic mechanism of a sulfonamide?

A

Inhibit dihydropteroate synthetase (inhibit PABA incorporation into dihydropteroic acid)

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2
Q

Sulfonamides alone are bacteri_____

A

Bacteriostatic

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3
Q

Trimethoprim basic mechanism

A

Inhibits dihydropteroate reductase (inhibit purine formation)

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4
Q

Trimethorpim alone is bacteri_____

A

Bacteriostatic

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5
Q

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

A

Bactericidal

Decreases resistance
Broadens spectrum of activity

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6
Q

Sulfonamides

Mechanisms of Resistance

A

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

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7
Q

Trimethoprim

Mechanisms of Resistance

A

Production of resistant dihydropteroate reductase enzyme

Change cell permeability

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8
Q

TMP-SMX Spectrum of Activity

A
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
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9
Q

TMP-SMX Absorption

A

IV or PO. Rapidly and completely absorbed

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10
Q

TMP-SMX Distribution

A

Good distirbution to urine, lungs, prostate, CSF

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11
Q

TMP-SMX Elimination

A

Eliminated by kidney and liver. Adjust dose in renal insufficiency

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12
Q

TMP-SMX Clinical Uses

A
Acute, chronic, recurrent UTIs
Bacterial prostatitis
Skin infections from CA-MRSA
Norcardia
Pneumocystis carinii
Stenotrophomonas maltophilia
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13
Q

TMP-SMX Adverse Effects

A

Nausea, vomiting
Leukopenia, thrombocytopenia
Rash
Crystalluria

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14
Q

TMP-SMX Drug Interactions

A

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

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