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1
Q

Fluroquinolones

A

Ciprofloxacin
Levofloxacin
Moxifloxacin

2
Q

Fluroquinolones - Mechanism of Action

A

Inhibits DNA gyrase (topoisomerase II)
That blocks DNA synthesis by preventing DNA unwinding
Acts on Gram -ve

Inhibits Topoisomerase IV
Prevents separation of DNA during division
Acts on Gram +ve

3
Q

Fluroquinolones- NOT effective against which species

A

MRSA
Anerobic
E Coli
May lead to C Diff

4
Q

Fluroquinolones- MechAnism of Resistance

A
  • mutation of DNA gyrase
  • enhanced drug efflux
  • decreased influx
5
Q

Fluroquinolones- Properties

A
  • newer drugs are fluoridated
  • active against G+ and G-
  • used against resp, skin, urinary, bone, kidney, ear
  • concentration dependent killing
6
Q

Fluroquinolones- Classification

A

Strong against Gram - & better against + Ciprofloxacin, Levofloxacin

Strong against both Moxifloxacin

7
Q

Ciprofloxacin - Major Indications

A

Gram - (esp. Pseudomonas)

Complicated UTI
Traveler’s diarrhea
Drug resistant -ve rods
PPx/Tax - anthrax

8
Q

Levofloxacin and Moxifloxacin - Major Indications

A

Gram -ve rods and cocci
Some anerobes
Staph and Strep
Legionella TB

Community acquired atypical Pneumonia
Non-TB mycobacterium

9
Q

Fluroquinolones - ADME

A
  • absorption impaired by metals (antacids)
  • usually orally admin
  • large volume of distribution
  • readily excreted in urine (need dose adj for renal)
  • exception: moxifloxacin has hepatic tox,
10
Q

Fluroquinolones - AE

A

-GI
-damage to growing cartilage
-tendonitis rupture
can occur early on or months after treatment
usually achilles rupture (50% bilateral)
discontinue if there are sign of tendon pain/swelling

11
Q

Fluroquinolones - More Tox

A
  • acute psychosis in patients taking theophylline or NSAID
  • QT prolongation (maxi and levo)
  • should not generally be given to pregnant women or kids (except CF)
  • may interact with P450
12
Q

DNA Synthesis Inihibitors

A

antifolates

fluroquinolones

13
Q

Antifolates (sulfonamides)

A

sulfamethoxazole (SMX)
trimethoprim
combo - TMP/SMX

14
Q

Folates in Metabolism do what?

A

involved in aa as well as nucleic acid synthesis , so need in both DNA and RNA replication/transcription

  • IN BACTERIA ONLY - PABA goes to dihydrofolic acid (folate) via dihydropteroate synthase (SMX acts on this enzyme)
  • IN HUMANS AND BACTERIA - folate converts via dihydrofolate reductase to tetrahydrofolic acid (which converts to purine). TMP acts on DHFR
15
Q

TMP is selective for what?

A

Prokaryotic DHFR

16
Q

where do we get folate from?

A

our diet

17
Q

Resistance to Sulfonamides

A
impaired uptake
increased efflux
mutation in dihydropteroate synthase
mutation leading to increased PABA synthesis
cross-resistance common
18
Q

What do you need to do when taking sulfonamides?

A

Drink lots of water, because the sodium salts can precipitate.

19
Q

What is cotrimoxazole?

A

SMX/TMP PO (Bactrim) - combination is bacteriocidal

20
Q

Cotrimoxazole - Indications

A

uncomplicated UTI/prostatitis
otitis/sinusitis
MRSA skin and soft tissue

21
Q

Sulfonamides - ADME

A
t1/2 relatively short
gets into CNS/CSF
no no if pregnant
hepatic metabolism 
excreted in urine - conjugated metabolites may precipitate in acidic urine - alkalize
22
Q

Sulfonamides - AE

A
  • hypersensitivity (1-2 weeks) less than 5%
  • hematopoietic toxicity (G6PD deficiency)
  • newborns can’t excrete - kernicterus (bilirubin in the CNS)