Lec. 9: Fluoroquinolones Flashcards

1
Q

What exhibits inhibition of bacterial DNA gyrase, inhibits DNA synthesis, and is bactericidal?

A

Fluoroquinolones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A mutation in what can lead to resistance to fluoroquinolones?

A

Mutation in the quinilone resistance determining region (QRDR) of DNA gyrase enzyme.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Fluroquinolones decrease with ? containing Al+++ or Mg++ and decrease with ? containing Fe++ or Zn++.

A
  1. Antacids

2. Dietary supplements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What generation of fluoroquinolones has increased gram-negative and systemic activity, improved pharmacokinetics, and fewer side effects? Give five examples.

A

2nd generation

  1. Ciprofloxacin
  2. Enoxacin
  3. Lomefloxacin
  4. Norfloxacin
  5. Ofloxacin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What generation of fluoroquinolones has extended activity against gram-positive organisms and has broad gram-negative coverage? Give three examples

A

3 generation

  1. Grepafloxacin
  2. Levofloxacin
  3. Sparfloxacin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Fluoroquinolones inhibit P450 system, cause photosensitivity reactions, and causes prolongation of QT interval. Which drug causes a definite risk of QTc prolongation?

A

Sparfloxacin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Are fluoroquinolones a broad or narrow spectrum drug?

A

Broad spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

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

A
  1. Sulfonamides

2. Trimethoprim

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What inhibits utilization of p-amino-benzoic acid (PABA) in the synthesis of folic acid?

A

Sulfonamides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sulfonamides can develop resistance by what four methods?

A
  1. Alteration in enzyme requiring PABA
  2. Increased inactivation of drug
  3. Alternative metabolic pathway
  4. Increased production of PABA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

T or F. Sulfonamides distribute to all body tissue, including CSF and pass the placental barrier and into great milk.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sulfonamides can be used to treat what three things?

A
  1. Urinary tract infectoins
  2. Susceptible infections of the eye
  3. Chronic inflammatory bowel disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What has the following adverse effects?

  1. Crystalline aggregates in urinary tract
  2. Hematologic disorder with G6PD deficiency
  3. Hypersensitivity
  4. Drug potentiation (it will bind serum albumin)
A

Sulfonamides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What inhibits the reduction of dihydrofolate to tetrahydrofolate, is highly selective for bacterial enzyme, and resistance occurs with alteration in enzyme affinity?

A

Trimethoprim

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does trimethoprim tend to concentrate in the body?

A

Prostate and vaginal fluids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What combination makes up Co-trimoxazole?

A

Trimethoprim-Sulfamethoxazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are two advantages of trimethoprim-sulfamethoxazole combination?

A
  1. Synergistic activity

2. Low toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is commonly used to treat uncomplicated lower urinary tract infections, genital infections, bacterial respiratory tract infections, nocardiosis, and infection due to pneumocystis carinii?

A

Trimethoprim-sulfamethoxazole combination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the four main categories of anti fungal drugs?

A
  1. Polyenes
  2. Flucytosin
  3. Azoles
  4. Caspofungin
20
Q

Polyene antifungals are characteristic of what two traits?

A

Amphotericin B and Nystatin

21
Q

What binds to ergosterol in fungal cell membrane and resistance is rare?

A

Polyene antifungals

22
Q

Amphotericin B is fungicidal or fungistatic?

A

Fungicidal

23
Q

Nystatin is fungistatic or fungicidal?

A

Can be either

24
Q

T or F. Amphotericin B and Nystatin exhibit both hydrophilic and hydrophobic portions.

A

True

25
Q

What is the action of polyene agents?

A

To form pores in the fungal cell membrane through which K+ and Mg++ can leak out.

26
Q

What is primarily used IV, has greater than 90% bound to beta-lipoprotein, and is has one non-lipid based form (deoxycholate) and three lipid-based forms (abelcet, ambisome, amphotec), and is not metabolized?

A

Amphotericin B

27
Q

What are five adverse effects of amphotericin B?

A
  1. Nephrotoxicity
  2. Thrombophlebitis
  3. Fever an dchills
  4. Hypersensitivity reaction
  5. Shock-like hypotension
28
Q

Amphotericin B is preferred for treatment against ? infections and it should not be used during pregnancy.

A

Deep fungal infections

29
Q

Nystatin should never be given ? b/c of unacceptable systemic toxicity. Only administer it either ? or ?.

A
  1. Paraenterally
  2. Topically
  3. Orally
30
Q

What is often used to treat candidal infections of the mucosa, skin, and intestinal tract?

A

Nystatin

31
Q

Mammalian cells do not have ?, which converts 5-Flucytosine to 5-FU.

A

Cytosine Deaminase

32
Q

What drug is used to stop thymidylate synthase from converting dUMP to dTMP?

A

5-Flucytosine

33
Q

What is can be fungicidal or static, inhibits thymidylate synthase and DNA synthesis, is deaminated to 5-fluorouracil, is “almost always used in combination with Amphotericin B?”

A

5-Flucytosine

34
Q

T or F. 5-Flucytosine does not penetrate the CSF.

A

False. 5-Flucytosine does penetrate the CSF.

35
Q

What is the effect of clearance on 5-flucytosine when given with Amphotericin B?

A

Clearance is reduced

36
Q

What is a broad spectrum anti fungal agent that inhibits synthesis of ergosterol (necessary sterol for fungal cell membrane)?

A

Imidazole Antifungal agent

37
Q

What drug inhibits P450 enzyme (causing potential increase in serum levels of concurrent drugs), but does not inhibit P450 isozyme use for androgen synthesis, and is used to treat candidiasis, coccidiomycosis, and cryptococcal meningitis?

A

Fluconazole

38
Q

What anti fungal drug is used to treat histoplasmosis, blastomycosis, aspergillus, and cryptococcus, and is a potent inhibitor of CYP3A4?

A

Itraconazole

39
Q

What drug exhibits genetic polymorphism (CYCP2C19 deficiency = increased concentration), is contraindicated with drugs that induce P450 (rifampin, rifabufin, carbamazapine, long acting barbiturates), and is used to treat invasive aspergillosis, scedosporium, fusarium, and invasive fluconazole-resistant candida?

A

Voriconazole

40
Q

What are three pharmacological properties of oral azole agents? Name the drug which fits each property.

A
  1. Easily crosses to CSF (Fluconazole)
  2. Hepatic elimination (Itraconazole and Voriconazole)
  3. Renal elimination (Fluconazole)
41
Q

What is an anti fungal drug that is given as a topical application for mucosal and cutaneous fungal infections, and if swallowed can increase hepatic enzymes in the plasma?

A

Clotrimazole

42
Q

What inhibits alpha (1,3) D-glucan synthesis, which are integral components of fungal cell WALL?

A

Caspofungin

43
Q

Metronidazole with lithium leads to what?

A

It inhibits renal excretion of Li++, leading to elevated blood levels and Li++ toxicity

44
Q

What effect is produced when metronidazole interacts with alcohol?

A

Disulfiram effect

45
Q

Erythromycin, clarithromycin, or metronidazole with warfarin or anisindione lead to what?

A

An increased risk of bleeding in anti coagulated patients.