Comparative and Veterinary Pharmacology

4.4 Alpha 2 Adrenergic Agonists

The use of alpha 2 adrenergic agonists in domestic animals has led to a better
understanding of the mechanisms of action of these drugs. The existence of receptor
subtypes has been recognised, leading to a range of actions. Three main subtypes of
the alpha 2 receptor have been identified, although unlike the opioids, for which
relatively pure mu agonists such as fentanyl exist, the clinically available alpha
2 agonists exert their effects on more than one receptor subtype. Unlike other
analgesic classes, the human applications for alpha 2 agonists as analgesics are
limited. Related to this, research data are sparse; however three agents are in
common veterinary usage, for both their sedative and analgesic properties. Xylazine

Table 5Doses and intervals for NSAIDs in farm animals

Drug Cow Horse Pig Sheep

Acetylsalicylic acid (oral)

6–12 h

• 25 10 50–100

Carprofen

24 h

1.4 0.7 2–4 1.5–2

Flunixin

24 h

2.2 1.1 1–2 2

Ketoprofen

24 h

3 2.2 3 –

Phenylbutazone

(oral) 24 h

• 2.2 – 10

All doses are in mg/kg for subcutaneous or intravenous injection except

where oral administration is indicated. Data from Bishop ( 1998 ); Thurman

et al. ( 1996 ) and Dobromylskyj et al. ( 2000 )

Table 6Doses and intervals for NSAIDs in companion animals

Drug Dog Cat Rabbit

Acetylsalicylic acid

(oral) 12 h

10–25 10–25 (48 h) 100

Carprofen

24 h

4 2–4 4

Flunixin

24 h

11 1

Ketoprofen

24 h

22 3

Meloxicam

24 h

0.2 0.2 0.2

Phenylbutazone

(oral) 24 h

20 24 (48 h) –

Tolfenamic acid 4 4 –

Vedaprofen 5 – –

Deracoxib 3–4 4 –

Firocoxib 5 5 –

All doses are in mg/kg for subcutaneous or intravenous injection except

where oral administration is indicated. Data from Dobromylskyj et al. ( 2000 )

180 A. Livingston