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Pharm Exam 2 > Antibiotics 5 - Sulfonamides and Quinolones > Flashcards

Antibiotics 5 - Sulfonamides and Quinolones Flashcards

1
Q

(sulfonamide) ______ was inactive in vitro

But this is a prodrug of the active ________

A

Prontosil

p-aminobenzenesulfonamide

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2
Q

Sulfanilamide (pharmacologically active) is used to treat ____ infections

A

Vaginal candida

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3
Q

MOA of sulfonamide antibiotics

A

Competitively inhibits the incorporation of PABA into folic acid

by inhibiting the enzyme dihydropteroate synthase

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4
Q

What reaction does dihydropteroate synthase catalyze?

What are the following steps in this pathway?

A

Dihydropteroate diphosphate -> Dihydropteroic acid

**next steps: conversion to DHF acid -> THF acid –> methyleneTHF acid –> Thymine –> DNA

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5
Q

Sulfonamides are bioisosteres of ____

A

PABA

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6
Q

There is a significant difference in ____ between PABA and sulfanilamide

What does this mean for the drug?

A

Acidity (pKa)

PABA = 6.5 Sulfanilamide = 10.4

This causes sulfanilamide to be 1000x more neutral as a drug

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7
Q

What two effects does attaching electron-withdrawing heteroaromatic rings to the sulfonamide nitrogen?

A

Increases ACIDITY = increased stability = increased potency**

This also decreases crystalluria in the urine

**essentially makes it more similar to the normal metabolite

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8
Q

Sulfonamides in general inhibit…

A
  • Gram + and -
  • Nocardia
  • Chlamydia trachomatis
  • Enterics (e.coli, kleb, salmonella, shig, enterobact)
  • some protozoa and fungi
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9
Q

Sulfamethoxazole combined with ____ is important for treatment of _______

A

Trimethoprim

PCP (in aids)

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10
Q

Trimethoprim inhibits _____

A

Dihydrofolate reductase

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11
Q

Most common sulfa

A

Sulfisoxazole

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12
Q

sulfisoxazole and sulfamethoxazole are mainly used to treat ________

A

uncomplicated UTI

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13
Q

What is triple sulfa and what does it treat?

A

1:1:1 mix of -benzamide, -acetamide, -thiazole

Treatment of Gardnerella vaginalis

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14
Q

Sulfasalazine is a____ that is not…

What is the metabolism?

A

prodrug, …not absorbed well in GIT

**metabolized to sulfapyridine and 5-aminosalicylic acid

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15
Q

Long acting sulfonamide

A

Sulfadoxine

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16
Q

Sulfadoxine is used with _____ to treat _____

A

pyrimethamine

malaria

(pyrimethamine inhibits DHFR in p. falciparum)

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17
Q

Sulfadiazine is used with _____ to treat _____

A

pyrimethamine

Toxoplasma gondii

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18
Q

Sulfonamide derivative examples (3)

A
  1. Carbonic anhydrase inhibitors (acetazolamide)
  2. Thiazides (HCTZ)
  3. Hypoglycemic agents (tolbutamide)
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19
Q

Most commone AE’s of sulfonamides (6)

A
  1. Rash
  2. Photosensitivity
  3. Drug fever
  4. Stevens-Johnson syndrome
  5. Crystalluria
  6. Hematopoietic disturbances (HA, AA, Granul, Thromb)
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20
Q

What three mutations can cause resistance to sulfonamides

A

Overproduction of PABA

Dihydropteroate synthase

Decrease in cell permeability

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21
Q

Bactrim composition

A

400mg SMX

80mg TMP

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22
Q

PK of TMP compared to SMX

A

absorbed 85=90%

distributed more rapidly than SMX

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23
Q

SMX distribution and clearance (description)

A

wide distribution

rapid clearance

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24
Q

Why isnt SMX as widely distributed as TMP

A

Differences in lipophilicity

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25
Tissue ratio of SMX:TMP
1:2 to 1:5
26
Short half life sulfas
Soxazole methizole
27
Intermediate half life sulfas
Diazine methoxazole
28
Sulfa metabolism mechanism
VIa N-4 N-acetylation (in some cases N-1 glucuronidation)
29
Toxic metabolites of sulfa
**Hydroxylamine** and **nitroso** metabolites
30
First gen Quinolones have limited ___ activity
G+
31
FIrst gen quinolones are only useful for
lower UTIs
32
Two examples of First gen quinolones
Nalidixic Acid Oxolinic acid
33
Second gen quinolone structure difference
Fluuorine ata C6 Heterocyclic ring (usually piperazine) at C7
34
Norfloxacin and levofloxacin shows a 40-100x poteny over nalidixic acid against...
most gram negatives incl. pseudomonas
35
Second gen quinolones have an extended activity against
G+ and mycoplasma
36
3rd and 4th gen quinolones often have \_\_\_\_\_
multiple Fluorine atoms
37
Best 3rd/4th gen for G-
Ciprofloxacin
38
Which quinolone is a last resort?
Moxi
39
topoisomerases (TI) and gyrases cleave DNA by ...
carrying out nucleophilic attack on a phosphodiester linkage --\> one strand is free and one is enzyme linked
40
Nucleophile used by TI/gyrase
phenolic OH group of Tyrosine
41
TI-catalyzed reaction is \_\_\_\_\_ The equilibrium tends to favor...
Reversible in favor of the uncleaved DNA
42
Most common use for quinolones
UTI
43
Second and Third most common use for quinolones
Prostatitis STD
44
Chlamydia trachomatis quinolones
ofloxacin + sparfloxacin
45
quinolone for N gonorrheae and H. ducreyi
Ciprofloxacin
46
First line for gonorrhea
ceftriaxone
47
Fourth and Fifth use for quinolones
GI Respiratory Tract Infections
48
Shigellosis quinolones
Nor Cipro O
49
Which quinolones WONT treat Bone, join, and soft tissue infections
Norfloxacin
50
\_\_\_\_ is 50% effective as monotherapy in diabetic foot infections
Cipro
51
Quinolones that have use against intraellular bacteria
Nor Cipro
52
Resistant organisms (to quinolones) have spontaneously occurring point utations in...
the A-subunit of DNA gyrase (results in a 16-fold increase in MBC for fluoroquinolones)
53
Less common mutation for quinolone resistance
the B subunit of DNA gyrase (results in a lower level of resistance)
54
Penetration of quinolone to gram negative bacteria is dependen on...
diffusion through **porin channels** (esp in *E. coli* and *pseuomonas*)
55
\_\_\_\_ should be avoided when giving quinolones
Under-dosing
56
Quinolones high or low oral BA? Wide or narrow distribution?
High oral BA Wide distribution
57
Route of clearance for all quinolones (with one exception)
Renal and hepatic | (oxafloxacin is 95% renal)
58
Interstitial fluid concentrations __________ from 4-24 hours
Exceed serum concentrations
59
Quinolones form insoluble chelates with \_\_\_\_\_\_
heavy metals
60
Major inactive metabolite is the \_\_\_\_\_\_
glucuronide at the 3 carboxyl position excreted in the urine
61
Most common AE for quinolones
N/V/D
62
Hallucinations and delirium an occur in patients who are also taking...
Theophylline NSAID
63
Quinolones are associated wih ____ (as an AE)
peripheral neuropathy
64
Why shouldnt you give quinolones to kids?
May **damage growing cartilage** and cause **arthropathy** (reversible)
65
Lomefloxacin AE
Photosensitivity
66
Gatifloxacin AE
Hyper/Hypoglycemia in diabetic patients
67
Exception to the "dont give to kids" rule for quinolones
**Pseudomonal infections** in kids with CF (High mortality rate, benefits\>risks)

Pharm Exam 2 (12 decks)

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