Horses rectal

An advantage of rectal over oral administration of lipid-soluble drugs is partial avoidance of the first-pass effect. The extent to which the first-pass effect is avoided appears to be less in dogs than in humans. Because venous drainage of the rectum of the horse. 

Atropine is a potent inhibitor of intestinal motility (Adams et al 1984, Roger Ruckebusch 1987). It is most frequently applied topically to the cornea to promote mydriasis and anecdotal reports suggest that the absorption of atropine from this site may disrupt intestinal motility (see Ch. 13). A single s.c. dose of atropine (0.02mg/kg) can be given safely to most horses. Dose rates of 0.02-0.04 mg/kg may facilitate evacuation of the rectum in horses with a rectal tear. 

Steel C M, Bolton J R, Preechagoon Y et al 1999 Unreliable rectal absorption of cisapride in horses. Equine Veterinary Journal 31 82-84 Thillainayagam A V, Hunt J B, Farthing M J 1998... 

Corveleyn S, Deprez P, van der Weken G et al 1996 Bioavailability of ketoprofen in horses after rectal administration. Journal of Veterinary Pharmacology and Therapeutics 19 359-363... 

The tt2 agonists can produce profuse sweating, cause mydriasis (Kamerling et al 1988) and decrease the hematocrit (Wood et al 1992) in horses. They also decrease rectal temperature and suppress shivering in foals (Robertson et al 1990). 

Butorphanol is used as an analgesic in horses. Butorphanol (0.1 mg/kg i.v.) increased the pain threshold in a rectal balloon model in mares (Skarda Muir 2003). It had analgesic efficacy for 60 min in a cecal balloon model (Muir Robertson... 

Hug C G (eds) Pharmacokinetics of anaesthesia. Blackwell, Boston, MA, p. 157 Riedesel D H, Hildebrand S V 1985 Unusual response following use of succinylcholine in a horse anesthetized with halothane. Journal of the American Veterinary Medical Association 187 507-508 Robertson S A, Carter S W, Donovan M et al 1990 Effects of intravenous xylazine hydrochloride on blood glucose, plasma insulin and rectal temperature In neonatal foals. Equine Veterinary Journai 22 43-47 Roger T, Bardon T, Ruckebush Y 1994 Comparative effects of mu and kappa opiate agonists on the cecocolic motility In the pony. Canadian Journal of Veterinary Research 58 163-166... 

Cook, G., Papich, M.G., Roberts, M.C. Bowman, K.F. (1997) Pharmacokinetics of cisapride in horses after intravenous and rectal administration. American Journal of Veterinary Research, 58, 1427-1430. 

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