Oral antimicrobial medication for Chickens

Oral Antimicrobial Medication
Pharmacokinetics in Chickens
by
DGS Burch BVetmed MRCVS
Octagon Services Ltd Copyright © June 2002
On-line at: www.octagon-services.co.uk

Notes to assist use of this spreadsheet:
These data give an overall pattern for an antimicrobial, obviously each reference or study has been carried out in a different way so the results may vary between studies.
1. Dose rate is usually given by gavage as a bolus dose in classical pharmacokinetic studies but for practical use in water studies are described. Estimated dose rates have an 'e' denoting them for comparative use.
2. Cmax is the peak level found in serum after administration and is the highest level that can be achieved with a certain antimicrobial at a certain dose.
Administration by water usually gives a much lower figure because the drug is given over a 24-hour period and feed slows the passage and sometimes affects the absorption of some compounds.
3. C 12hours is the level of antimicrobial found in the blood 12 hours after administration. Products with a fast clearance usually have gone by 12 hours. When given in water levels may be lower but can persist for longer periods.
4. Steady state is the level achieved after in water medication and the average level that is achieved over a 24 hour period.This is the most important level for many antimicrobials as they act by inhibiting the growth of the bacteria and require a prolonged exposure. Concentrations in other target tissues like lung or airsac are also important when dealing with infections in those areas.
5. Protein binding of an antimicrobial is important as it can affect the effective concentration of that particular antimicrobial against an organism. High binding is therefore not usually good.
6. Bioavailability is the comparison of the absorption of a product from the gut in comparison with a dose given intravenously (assumed 100%). It is important if you want an antimicrobial to go from the gut to a target in the body. A high bioavailability means a drug is likely to work systemically although other factors can affect this. Feed may interfere with the absorption and bioavailability of a product.
7. Lung concentration is important if you want to treat an infection in the lung. Some antibiotics specifically concentrate in lung tissue and air sacs.

Overall, understanding the pharmacokinetics of an antimicrobial, knowing its level at the site of infection and the Minimal Inhibitory Concentration (MIC) of an organism to treat, can help the veterinarian to decide on what product, what dose, how it should be administered, for how long and improve the therapeutic control of the disease and thereby reduce the chances of developing antimicrobial resistance.

Pharmacokinetics graph for antimicrobials medication

The data in the following table are provided free and without obligation, for demonstration purposes - readers should seek expert guidance before taking decisions requiring critical product specifications.

Antimicrobial	Reference	Dose rate mg/kg bwt	Water Conc. ppm	C max µg/ml	C12hrs µg/ml	Steady state µg/ml	Protein bind %	Bio- avail %	Lung conc. µg/ml

Tiamulin	Laber & Schutze, 1976/77	25		1.7	0.17
Tiamulin		50		3.56	0.59
Tiamulin	Ziv, 1981		125	0.65		0.38	50	90
Tiamulin			250	1.4		0.78	50	90

Tylosin	Laber & Schutze, 1976	50		4.2	0.25
Tylosin	Ziv, 1981		500	0.2		0.12	30
Tylosin	Iguchi et al,	50		3.48

Aivlosin	Iguchi et al,	50		6.8			70

Tilmicosin	Warren et al, 1997		75						1.5-2.3
								Airsac	2.4-3.3
Lincomycin	Soback et al,1987						23
Spectinomycin	Haagsma et al, 1991	33		0.08		0.05

Apramycin	Thomson et al, 1991	43				0.04			0.04
	Plus coccidiosis	43				0.06			0.17

Tetracycline	Brain et al, 1989		533	0.76		0.45

Oxytetracycline	Williams Smith, 1954	25		0.4	0.1		59
		50		0.7	0.2
		100		2	1.4

Chlortetracycline	Williams Smith, 1954	25		0.2	0.04
Chlortetracycline		50		0.7	0.14
Chlortetracycline		100		2	0.2
Chlortetracycline	Pollet et al, 1983	25		0.35	0.15
Chlortet + Citric acid		25		1.48	0.15
Chlortetracycline	Semjen et al, 1994	20		0.22
Chlortetracycline	Ziv et al,1997	16	200			0.2
Chlortetracycline		32	400			0.35
Chlortetracycline		64	800			0.55

Doxycycline	Anadon et al,1994	20		54.58	7
Doxycycline	Semjen et al, 1994	15		8.48
Doxycycline	Espigol et al,1997	11-15mg	100	2.2		1.9-2.2
Doxycycline	Anadon et al,1997	5		1.85					e5.5
Doxycycline	Laczay et al, 2001	10		4.47				73-61

Enrofloxacin	Baytril data		50	1.1		0.9
		10		1.4					2.4
Enrofloxacin	Martinez-Larranaga et al, 1994	10						64
Enrofloxacin	Villa et al, 1994						21
Enrofloxacin	Anadon et al, 1995	10		2.44				64
Enrofloxacin	Scheer et al, 1997		50	0.5					0.76
Enrofloxacin		10		0.88					1.49
Enrofloxacin	Ganiere et al, 1997	10	60-65			0.82-0.86	21
Enrofloxacin	Knoll et al, 1999	10		1.88	0.25			60-80
Enrofloxacin	Bregante et al, 2000						22-51

Danofloxacin	Knoll et al. 1999	5		0.47	0.08			100
Danofloxacin	Anadon et al,1997	5		1.85
Danofloxacin	Advocin data	5				0.2
Danofloxacin	EMEA EPAR	5				0.125			0.3
Danofloxacin	Bregante et al, 2000						20-29

Flumequine	Moutafchieva et al 1994	9.2				0.9
Flumequine	Imequyl data	12		5	2	2.4
Flumequine		18		9.2	1.8
Flumequine	Villa et al, 1994						28

Norfloxacin	Anadon et al, 1991	8		1.98				57
Norfloxacin	Anadon et al 1992	8		2.89	0.25
Norfloxacin	Ramadan et al, 1994	8		3.05-3.46				75
Norfloxacin	Chen et al, 1994	10						61
Norfloxacin	Bregante et al, 2000						6

Marbofloxacin	Diaz et al, 2000	2		1.05

Fleroxacin	Martinez- Larranaga et al, 2000	4		1.33					e4

Difloxacin	Dijkstra, 1997	10		0.7		0.19-0.33
Difloxacin	Bregante et al, 2000						e10-37

Ciprofloxacin	Villa et al, 1994						30

Ofloxacin	Liu & Fung, 1997	10		5.79				100

Sarafloxacin	Bregante et al, 2000						28-30

Sulphadiazine	Dagorn et al, 1991	20				6.81		100	3.27
Sulphadiazine	Bousquet et al, 1994	38-51				8.7-20.8			2.7-6.2
Sulphadiazine	Villa et al, 1997						35
Sulfachloropyradazine	Cosumix data	20		34

Trimethoprim	Cosumix data	4		1.7
Trimethoprim	Dagorn et al, 1991	4				0.11		85	0.62
Trimethoprim	Bousquet et al, 1994	7-10mg				0.1-0.4			0.7-1.8

Penicillin	Villa et al, 1997						63
Penicillin V	Meijer & Ceyssens, 2000	15		0.4				69

Ampicillin	Villa et al, 1997						26

Amoxycillin	Aerts et al, 1994	25		2.7
Amoxycillin		20		2
Amoxycillin		10 bid		0.8
Amoxycillin		5 bid		0.5
Amoxycillin	Anadon et al, 1996	10		160	40			63
Amoxycillin	Villa et al, 1997						33
Amoxycillin	Ziv et al, 1997		100	0.43-0.52		0.36-0.41
Clavulanic acid			25	0.16-0.27		0.13-0.21
Amoxycillin			200	0.89-1.04		0.51-0.66
Clavulanic acid			50	0.46-0.49		0.29-0.38
Amoxycillin			400	1.82-1.93		1.17-1.45
Clavulanic acid			100	0.85-1.0		0.57-0.71

Cephalexin	Ziv et al, 1997	54	500			0.39-0.53			0.1-0.2
Cephalexin		41-50	2000 pulse	5.53	<0.006				3
Cephalexin		71	2000 pulse + 500	5.18	0.4	0.4

Chloramphenicol	Anadon et al 1991	50						38

Antimicrobial	Reference	Dose rate	Water conc.	C max	C12hrs	Steady state	Protein bind	Bio- avail	Lung

Poultry technical papers on-line here: Index
Oral Antimicrobial Pharmacokinetics: Turkeys Pigs

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Poultry technical papers on-line here: Index Oral Antimicrobial Pharmacokinetics: Turkeys Pigs

Poultry technical papers on-line here: Index
Oral Antimicrobial Pharmacokinetics: Turkeys Pigs