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− | {{Unfinished}}
| + | ==Introduction== |
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| '''Halothane''' was one of the most widely used inhalation agents in veterinary patients. However, it has now been overtaken by other agents such as [[Isoflurane|isoflurane]]. It is most commonly used to maintain anaesthesia after induction with an [[Injectable Agents|injectable agent]], although it has also been used to induce anaesthesia when injection is not possible e.g. poor intravenous access. | | '''Halothane''' was one of the most widely used inhalation agents in veterinary patients. However, it has now been overtaken by other agents such as [[Isoflurane|isoflurane]]. It is most commonly used to maintain anaesthesia after induction with an [[Injectable Agents|injectable agent]], although it has also been used to induce anaesthesia when injection is not possible e.g. poor intravenous access. |
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| ==Pharmacokinetics== | | ==Pharmacokinetics== |
− | At room temperature, halothane is a liquid and so requires a [[Vaporisers|vaporiser]] before it reaches the patient. It needs to be stored in a darkened bottle due to ultraviolet degradation. It contains a preservative, Thymol, which can accumulate within the vaporiser The '''blood:gas partition coefficient''' is moderately low meaning that it is relatively insoluble in blood. This results in relatively rapid induction, recovery and depth change. The [[Inhalation agents#Minimum Alevolar Concentration|'''MAC''']] for halothane is approximately ''0.9%'', meaning it is highly potent. Halothane undergoes a degree of hepatic metabolism by the cytochrome P450 system found in hepatocytes. | + | At room temperature, halothane is a liquid and so requires a [[Vaporisers|vaporiser]] before it reaches the patient. It needs to be stored in a darkened bottle due to ultraviolet degradation. It contains a preservative, Thymol, which can accumulate within the vaporiser The '''blood:gas partition coefficient''' is moderately low meaning that it is relatively insoluble in blood. This results in relatively rapid induction, recovery and depth change. The [[Inhalation Agents#General Pharmacokinetics#Minimum Alveolar Concentration|'''MAC''']] for halothane is approximately ''0.9%'' in dogs and ''1.1%'' in cats, meaning it is highly potent. Halothane undergoes a degree of hepatic metabolism by the cytochrome P450 system found in hepatocytes. |
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| ==Adverse Effects== | | ==Adverse Effects== |
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| *Decreased cardiac output due to myocardial contraction depression. | | *Decreased cardiac output due to myocardial contraction depression. |
| *Decreased arterial blood pressure. | | *Decreased arterial blood pressure. |
− | *May cause cardiac arrhythmias. | + | *Sensitizes the myocardium to catecholamines so may cause cardiac arrhythmias. |
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| ===Respiratory System=== | | ===Respiratory System=== |
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| ==Contraindications== | | ==Contraindications== |
| Halothane should be avoided in patients with increased ICP, cardiac dysfunction, hepatic disease and susceptibility to malignant hyperthermia. | | Halothane should be avoided in patients with increased ICP, cardiac dysfunction, hepatic disease and susceptibility to malignant hyperthermia. |
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| + | {{Unfinished}} |
| + | [[Category:Inhalation Anaesthetic Agents]] |
| + | [[Category:To Do - Anaesthesia]][[Category:To Do - Drugs]] |