Fluoroquinolones

Fluoroquinolones

The fluoroquinolones are synthetic, broad-spectrum antibacterial agents with bactericidal activity. They exert their effects by binding to and inhibiting bacterial DNA-gyrase. This enzyme produces supercoiling of cellular DNA which is needed for bacterial DNA synthesis.

Description: The fluoroquinolones are broad-spectrum antibacterial agents with in vitro activity against many gram-negative and gram-positive organisms.

Mechanism of action: Quinolones rapidly inhibit DNA synthesis by promoting cleavage of bacterial DNA in the DNA-enzyme complexes of DNA gyrase and type IV  topoisomerase, resulting in rapid bacterial death.(1-3) As a general rule, gram-negative bacterial activity correlates with inhibition of DNA gyrase, and gram-positive bacterial activity corresponds with inhibition of DNA type IV topoisomerase.

Indications: Salmonellosis, Colibacillosis, Fowl cholera, Pseudomonas aeruginosa (enrofloxacin)

Dosage:
Chickens:
Turkeys:
Pigeons:
Enrofloxacin
10 mg/kg
10 mg/kg
15 mg/kg
Danofloxacin
-
6 mg/kg
-
Flumequine
18-20 mg/kg
-
-
Norfloxacin
15 mg/kg
- -
Difloxacin
10 mg/kg
- -


Drug interactions: Various drug-drug interactions can occur with the use of the quinolones. Absorption of the quinolones is significantly diminished with the concomitant use of compounds that contain multivalent metal cations such as aluminum, magnesium, zinc, iron, and calcium.

Residues: When given orally or by IM injection to laying hens, fluoroquinolone residues appear in eggs around 24 h after the first dose and persist in both yolk and albumen for several days after cessation of treatment.

Pharmacokinetics:

 FLUMEQUINE

 

Animal
Species
Mg/kg
Tmax
(Hr)
t 1/2
(Hr)

F(%)

Pigeons 10 IM ~2 1.44±0.33 22±9
60 IM ~4 1.69±0.12 23±9
60 IM ~2 1.57±0.33 6.7±2.5

 

ENROFLOXACIN

 

Animal Species

Mg/Kg
PO

Tmax
(Hr)

t1/2
(Hr)

F(%)

Chickens

5

2.50±0.86

---

80.1

10

1.64±0.04

14.23±0.46

64.0±0.2

 

6-7

59.6

 

4.29

80

0.119

5.81

89.2

4.3 ± 1.98

19.51 ± 2.60

 

20

4.4 ± 1.58

18.77 ± 4.11

 

Turkeys

10

4-6

 

 

Muscovy Duck

10

1.38±0.18

68

 

Pigeons

10-15

2.6-4.7

87-92

 

African grey parrot

5-15

2-3

51

 


 NORFLOXACIN

 

Animal
Species
Mg/kg
PO
Tmax
(Hr)
1/2
(Hr)
F(%)
Chickens 8 0.22±0.02 12.8±0.59 57.0±2.4
10 1.99±0.17 11.11±2.28  
Turkeys 10 1.94±0.08 9.07±1.00  
40 0.7    
Geese
10 2.39±0.18 10.65±2.41  

 

DANOFLOXACIN 

 
Animal
Species
Mg/kg
PO
Tmax
(Hr)
t 1/2
(Hr)
F(%)
Chickens*
5
0.50±0.01
6.98±0.18
100
1.5
6.62
99.2
Turkeys
6
2.13±2.56
9.74±2.93
78.37±17.35%

 * Different studies

 DIFLOXACIN

 
Animal
Species
Mg/kg
PO
Tmax
(Hr)
t 1/2
(Hr)
F (%)
Chickens
5
1.4
7.35
86.9