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Topic:Atropine
Atropine is a medication used in equine medicine primarily for its anticholinergic properties, which help to relax smooth muscles and dilate pupils. It is commonly administered in situations requiring the treatment of colic or the dilation of the pupils for ophthalmic examinations. Atropine works by inhibiting the action of the neurotransmitter acetylcholine, leading to decreased gastrointestinal motility and increased heart rate. In horses, its use must be carefully monitored due to potential side effects, such as decreased gut motility and risk of colic. This page compiles peer-reviewed research studies and scholarly articles that explore the pharmacokinetics, therapeutic applications, and safety considerations of atropine in equine veterinary practice.
Observations on the use of glyceryl guaiacolate as an adjunct to general anaesthesia in horses. Twenty-one horses undergoing clinical surgery and diagnostic procedures received 15% glyceryl guaiacolate followed by a rapid intravenous injection of a thiobarbiturate for induction of anaesthesia. Premedication was with atropine and acepromazine. Induction was smooth and free from problems apart from transient apnoea in some horses. Maintenance of anaesthesia was with oxygen and halothane administered by means of a closed circle system with soda-lime absorber and with the vaporiser out of circuit. During the period immediately following induction, the heart rate increased and the respiratory...
Gastrointestinal complications associated with the use of atropine in horses. Atropine sulfate was given at 2 dosages (0.044 mg/kg, 0.176 mg/kg) to clinically normal ponies in order to evaluate the drug's effect on the gastrointestinal tract. Intestinal motility, as assessed by ausculation of borborygmus, was stopped 30 minutes after injection, but it gradually returned to normal within 12 hours. Signs of abdominal pain developed in 3 of 10 ponies. In 3 clinical cases of gastrointestinal disorder, prior atropine treatment was confusing to the diagnostician and resulted in delayed surgical treatment in 1 case. It was concluded that atropine should not be used for allevia...
Arterial baroreflex control of heart rate in the horse, pig, and calf. The heart rate (HR) response to stepwise changes in mean arterial pressure (MAP) produced by methoxamine and sodium nitroprusside was studied in conscious horses, pigs, and calves. The respective steady-state arterial baroreflex sensitivities (delta HR/delta MAP expressed as beats min-1 . mm of Hg-1) were -1.20, -1.21, and -0.39 for decreasing MAP and -0.08, -0.91, and -0.56 for increasing MAP. After parasympathetic nervous system (PNS) blockade with atropine, the reflex sensitivity to decreasing MAP in horses and the pigs decreased to -0.62 and -0.65, respectively (P less than 0.05), whereas ...
Clinical bronchography in the horse: development of a method using barium sulphate powder. A method for performing bronchography in standing nonanaesthetized horses was developed. Bronchography was performed by insufflating the previously intubated trachea with a mixture of 120 to 200 g of finely powdered barium sulphate mixed with 3 to 7 g of powdered methyl cellulose. The mixture was delivered from an ether vaporiser into which compressed air was blown. Premedication with atropine sulphate immediately before insufflation minimised bronchoconstriction. Satisfactory bronchograms with contrast visible down to the seventh and eighth bronchial divisions were obtained in 80 per cent of ...
Technique for reversible vagal blockade in the standing conscious pony. A surgical technique is described for preparation of chronic cervical vagal loops in ponies. Vagal blockade was induced by circulating methanol (-2 C) through coils which enclosed the loops. Vagal blockade increased tidal volume, heart rate, and systemic blood pressure and decreased respiratory rate. Atropine, given at a dose of 0.04 mg/kg IV, increased heart rate and systemic pressure but did not alter respiratory variables, indicating that vagal cooling caused both afferent and efferent blockade. The effects of vagal blockade were rapidly reversed when refrigerated coils were removed.
Intravenous anaesthesia in horses after xylazine premedication. The effects of combining large doses of xylazine (1.1 mg per kg intravenously) with ketamine, methohexitone and thiopentone were studied in four experimental ponies. Onset of anaesthesia was more delayed after ketamine than after the barbiturates. Assessment of smoothness of induction and recovery indicated that all three combinations were effective and acceptable. Injection of xylazine was followed by atrioventricular (A-V) block which could be prevented by the prior administration of atropine. Blood pressure was well maintained with all three combinations of drugs. Arterial oxygen tension de...
Chronic obstructive pulmonary disease (COPD): effects of bronchodilator drugs on normal and affected horses. The effects of the bronchodilator drugs, atropine, isoprenaline and terbutaline, on normal horses and on horses affected with chronic obstructive pulmonary disease (COPD), were assessed by pulmonary function tests and clinical examination. Normal horses were not affected but COPD horses responded by a marked decrease in intrathoracic pressure, a decrease in respiratory rate, an initial decrease followed by an increase in arterial oxygen partial pressure and clinical improvement after treatment with all 3 drugs. These changes were temporary.
The effect of some anti-diarrhoeal drugs on intestinal transit and faecal excretion of water and electrolytes in the horse. The effect of morphine, Tinct. opii, loperamide, pethidine and atropine on intestinal transit and the faecal and urinary excretion of water and electrolytes was studied in ponies. The rate of passage of a particulate marker was slowed by morphine, hastened then slowed by loperamide and Tinct. opii, and hastened by atropine. The liquid marker was slowed by Tinct. opii and hastened then slowed by the other drugs. Only loperamide decreased the faecal sodium excretion. This drug also decreased faecal water and weight; it appeared worthy of clinical trial in diarrhoea. Tinct. opii decreased by morp...
General anesthesia in pleasure horses. Anesthetic management of the pleasure horse consists of the appropriate selection and administration of pre-anesthetic medications including anticholinergics, tranquilizers and narcotics followed by appropriate techniques of anesthetic induction. The anesthetic induction must vary somewhat for the pleasure horse practice since many of the procedures are completed on farms and ranches. As a result the inducing of anesthesia will frequently be with the same agent which will be used to maintain anesthesia. Noticeably will be the reduction and duration of anesthesia and surgical time. The inductio...
Cardiovascular effects of amphetamine in the horse. Each of nine horses was treated with amphetamine alone, with atropine alone, and with amphetamine and atropine in combination. Cardiac effects of these drugs were studied by electrocardiography during resting and exercising states and immediately after exercise. Although each treatment increased heart rate significantly during the resting state, only the amphetamine plus atropine treatment increased heart rate significantly during exercise. Decrease in heart rate immediately after exercise differed significantly for each treatment; the most rapid decrease in heart rate was found after the amph...
Influence of halothane and catecholamines on heart rate and rhythm in the horse. 1. Ventricular ectopic beats were recorded in eight of thirteen conscious horses following the intravenous administration of adrenaline in doses of 3 mug/kg. Following pre-treatment with either atropine sulphate (0.1 mg/kg) or propranolol hydrochloride (0.1 mg/kg), the same dose level of adrenaline failed to produce ventricular ectopic beats.2. Halothane anaesthesia sensitized the equine heart to the arrhythmogenic actions of adrenaline; the incidence and duration of ventricular arrhythmias being greater than in conscious animals. In comparison with the findings in conscious horses, ether anae...
