DNA and Metabolic Toxins

Question 1

What are the 3 types of fluoroquinolones?

Answer 1

1. cipro
2. Levofloxacin
3. Moxifloxacine

Question 2

What is the mech of action of fluoroquinolones?

Answer 2

Direction inhibitors of DNA synthesis, inhibits bacterial enzymes (DNA gyrase/topoiserase), leading to DNA cleavge and DNA damage, leading to cell death

Question 3

What is the spectrum of activity of fluoroquinolones?

Answer 3

1. most aerobic gram - bacilli
2. atypical pneimonia pathogens
3. gram + cocci
4. pseudomonas with cipro (cipro has weakest gram + activity)
5. levo and moxi are better with gram + like pneumoniae and anaerobes
   *ussualy respiratory infections, community acquired infections

Question 4

What is the pharmocology of fluoroquinolones?

Answer 4

1. well absorbed but cations can bind drug and limit systemic absorption
2. excelent bone and tissue penetration
3. renal elimination varaible (most need drug adjustemtns in renal failure)
4. Great bioavailability (IV serum levels= PO serum levels)

Question 5

Mech of resistant of fluoroquinolones?

Answer 5

1. inactivating enzymes
2. prevent drug acces (efflux pumps, altered premeability)
3. altered target site

Question 6

Adverse effects of fluoroquinolones?

Answer 6

1. Tendonitis/tendon rupture (concern for cartilage damage in peds)
2. prolonged QT interval
3. potential aneurysm

Question 7

What is trimethoprim-sulfamethoxazole (sulfonamides/bactrum)?

Answer 7

1. inhibits DNA synthesis/inhibits production of tetrahydrofolic acid needed to form NTPs
2. treat gram + cocci, MRSA, gram -, parasites, fungi
3. not active against strep
4. good CSF penetration, tissue penetration moderate
5. excreted in urine
6. Tx UTI, skin/soft tissue infection, community acquires MRSA, PCP pneumonia, but resistance is growing

Question 8

Advserse effects of sulfa?

Answer 8

1. anaphylais
2. skin rash
3. nephrotoxicity
4. kernicterus (build up of bilirubin in brain)
5. GI/kidney

Question 9

What are metronidazole?

Answer 9

1. DNA damage by reduction of nitro group (bactericidal)
2. Bacteroides/anaerobes (abdominal infections and protozoael infections)
3. IV, oral, topic prep
4. excellent bio avaiablity, rectal and vaginal absorption, good penetration, metabolized in liver, excreted in urin3
5. Adverse effects: GI, neuropathy, drug interaction with alcohol (induced a disulfiram-like reaction which includes nausea, vom, headache)