Lec. 9: Fluoroquinolones Flashcards
What exhibits inhibition of bacterial DNA gyrase, inhibits DNA synthesis, and is bactericidal?
Fluoroquinolones
A mutation in what can lead to resistance to fluoroquinolones?
Mutation in the quinilone resistance determining region (QRDR) of DNA gyrase enzyme.
Fluroquinolones decrease with ? containing Al+++ or Mg++ and decrease with ? containing Fe++ or Zn++.
- Antacids
2. Dietary supplements
What generation of fluoroquinolones has increased gram-negative and systemic activity, improved pharmacokinetics, and fewer side effects? Give five examples.
2nd generation
- Ciprofloxacin
- Enoxacin
- Lomefloxacin
- Norfloxacin
- Ofloxacin
What generation of fluoroquinolones has extended activity against gram-positive organisms and has broad gram-negative coverage? Give three examples
3 generation
- Grepafloxacin
- Levofloxacin
- Sparfloxacin
Fluoroquinolones inhibit P450 system, cause photosensitivity reactions, and causes prolongation of QT interval. Which drug causes a definite risk of QTc prolongation?
Sparfloxacin
Are fluoroquinolones a broad or narrow spectrum drug?
Broad spectrum
Pteridine + PABA to Dihydropteroid acid is blocked by ? and conversion of Dihydrofolic acid to Tetrahydrofolic acid is blocked by? These are sites of inhibition in folic acid synthesis
- Sulfonamides
2. Trimethoprim
What inhibits utilization of p-amino-benzoic acid (PABA) in the synthesis of folic acid?
Sulfonamides
Sulfonamides can develop resistance by what four methods?
- Alteration in enzyme requiring PABA
- Increased inactivation of drug
- Alternative metabolic pathway
- Increased production of PABA
T or F. Sulfonamides distribute to all body tissue, including CSF and pass the placental barrier and into great milk.
True
Sulfonamides can be used to treat what three things?
- Urinary tract infectoins
- Susceptible infections of the eye
- Chronic inflammatory bowel disease
What has the following adverse effects?
- Crystalline aggregates in urinary tract
- Hematologic disorder with G6PD deficiency
- Hypersensitivity
- Drug potentiation (it will bind serum albumin)
Sulfonamides
What inhibits the reduction of dihydrofolate to tetrahydrofolate, is highly selective for bacterial enzyme, and resistance occurs with alteration in enzyme affinity?
Trimethoprim
Where does trimethoprim tend to concentrate in the body?
Prostate and vaginal fluids
What combination makes up Co-trimoxazole?
Trimethoprim-Sulfamethoxazole
What are two advantages of trimethoprim-sulfamethoxazole combination?
- Synergistic activity
2. Low toxicity
What is commonly used to treat uncomplicated lower urinary tract infections, genital infections, bacterial respiratory tract infections, nocardiosis, and infection due to pneumocystis carinii?
Trimethoprim-sulfamethoxazole combination