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PC2 > Sulfonamides > Flashcards

Sulfonamides Flashcards

1
Q

Sulfonamides are bactericidal/bacteriostatic

A

bacteriostatic

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2
Q

Sulfonamide is a generic term for

A

derivatives of para-aminobensenesulfonamide

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3
Q

sulfonamide compounds used today

A

Bactrim and sulfadiazine

topical: mefenide, silver sulfadiazine, sulfacetamide

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4
Q

The structure prerequisites for activity are embedded in the

A

sulfanilamide

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5
Q

addition of the heterocyclic aromatic ring on sulfamethoxazole helps with

A

antibacterial activity

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6
Q

Bacteria synthesize their own ____ utilizing _____

A

folic acid; PABA

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7
Q

Sulfonamides are structural analogues of

A

PABA

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8
Q

Sulfonamides competitively inhibit

A

dihydroteroate synthase which is an enzyme responsible for incorporating PABA into the dihydropteroic acid

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9
Q

Sulfonamides will only affect organisms that

A

must synthesize their own folic acid

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10
Q

Synergy with trimethoprim:

A

potent inhibitor of dihydrofolate reductase which reduces tetrahydrofolate concentrations

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11
Q

TMP/SMX oral absorption

A

97%

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12
Q

TMP/SMX 1/2 life

A

8-10/10 hours

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13
Q

TMP/SMX elimination

A

sulfa: 30% free in urine and 70% acetylated in liver
TMP: 100% renal

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14
Q

Sulfadiazine oral absorption

A

100%

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15
Q

sulfadiazine 1/2 life

A

17 hours

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16
Q

sulfadiazine elimination

A

60% free in urine

40% acetylated

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17
Q

Dosing for pneumocystis jiroveci

A

15-20 mg/kg/day divided q8h (IV)

18
Q

Cystitis dosing

A

1 DS po q12h

19
Q

S. aureus ABSSSI dosing

A

1-2 DS po q12h

20
Q

Other indications for sulfonamides

A

prophylaxis, nocardia

21
Q

SMX/TMP SS

A

400mg/80mg

22
Q

SMX/TMP DS

A

800mg/160mg

23
Q

intensity of dosing regimen id driven by

A

organism and site of infections

24
Q

Dosing is based on

A

trimethoprim component

25
Q

which body weight should be used when obese?

A

adjusted

26
Q

Renal adjustment is needed/is not needed

A

needed

27
Q

Sulfonamide spectrum coverage

A

dark purple: s. pneumoniae, MSSA, MRSA

light purple: streptococcus

dark red: h, influenzae, m, catarrhalis, E. coli, klebsiella, p. mirabilis, morganella, enterobacter

light red: Neisseria

Misc: TMP/SMX activity against pneumocystis jiroveci, salmonella, shigella, vibrio, steno, nocardia, listeria

28
Q

Sulfonamide resistance mechanisms

A

permeability barrier/efflux (pseudomonas)
insensitive targets
-altered binding to dihydrofolate reductase; point mutations can minimize ability of TMP to bind, natural resistance for bacteriodes and clostridium and acquired resistance for e.coli, s.aureus, s.pneumoniae, h. influenzae
-altered binding to dihydropteroate synthase
; acquired resistance: e.coli, s.aureus, campylobacter, and h. pylori

29
Q

Resistance mechanisms can

A

easily be transferred to other organisms

30
Q

Sulfonamides adverse effects

A 
GI
hypersensitivity
photosensitivity
hyperkalemia 
increased serum creatinine 
interstitial nephritis or crystalluria 
pregnancy category D 
G6PD deficiency 
folate deficiency anemia can exacerbate anemia
31
Q

Sulfonamides are pregnancy category

A

D; 1st trimester congenital abnormalities

near term: increased risk for jaundice, hemolytic anemia, or kerniceterus (readily crosses placenta)

32
Q

TMP drug interactions

A

dofetilide, phenytoin, warfarin, digoxin

33
Q

TMP is an inhibitor of

A

CYP2C8 and OCT2

34
Q

SMX drug interactions

A

nephrotoxic agents
methenamine
elvitegravir

35
Q

SMX is an inhibitor and substrate of

A

CYP2C9

36
Q

TMP/SMX indications

A

1st line for pneumocystis (treatment and prevention), nocardia, s. maltophilia, B. cepacia
good activity for MRSA
inferior to beta lactams for MSSA
transition agent when susceptibilities are available (enterobacteriaceae)

37
Q

Sulfadiazine indications

A

treatment of toxoplasmosis

38
Q

Which of the following electrolytes do you monitor while on TMP/SMX?

a. megnesium
b. calcium
c. potassium
d. sodium

A

c

39
Q

Which antibiotic targets dihydrofolate reductase?

A

trimethoprim

40
Q

Which antibiotic targets dihydropteroate synthase?

A

sulfonamides

41
Q

TMP/SMX is the drug of choice for which of the following?

a. p. aeruginosa
b. e. coli
c. s. pyogenes
d. p. jiroveci

A

d

PC2 (18 decks)

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