Review on Commonly Used Veterinary Anesthetic Drugs in Small Ruminants

Abstract

Now a day a variety of drugs are on use for providing anesthesia in animals. Small ruminants, due to their anatomy and physiology, are not suitable for many of the anesthetic drugs. With strict consideration, some drugs are commonly used in these animals. Anesthetic drugs classified based on their action and efficacy. The commonly used local anesthetic agents include procaine, lidocaine and bupivacaine. Understanding the pharmacology of local anesthetics enables the anesthetists to predict the potency, speed of onset, duration of action and safety of a specific drug in a given clinical situation. A local anaesthetic disrupts ion channel function within the neuron cell membrane preventing the transmission of the neuronal action potential while general anesthetics like ketamine disrupt pathways within the cerebrum and stimulates the reticular activating center. Local anaesthetics affect all excitable tissues in the body, so toxicity can occur when sufficient amounts of the drug are absorbed into the circulation. General anesthesia (GA) is not commonly used in small ruminants as its administration results in several side effects such as; ruminal tympany, regurgitation of reticuloruminal contents, aspiration of refluxed material or saliva, hypoventilation, hypotension and fluid and electrolyte imbalances. Ketamine (injectable) is a commonly used general anaesthetic agent in veterinary practice. Injectable anesthetics offer the advantage of requiring less expensive equipment. Isoflurane (inhalant) provides a very rapid and smooth induction and recovery. Pre-anesthetic medications are used to decrease fear and apprehension, aid in restraint, decrease the amount of other anesthetic agents required and decrease side effects of induction drugs. These drugs are metabolized by the liver and excreted by the kidneys. Monitoring vital signs continuously during anesthesia will provide early warning of potential problems and emergencies that may be averted by appropriate and quick corrective actions.