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Alpha-2 Agonists (view source)

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==Actions==

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Alpha-2 agonists have a wide range of actions, due to the presence of alpha-2 receptors throughout the body. The actions most useful pharmacologically are '''sedation''', '''anxiolysis''' and '''analgesia'''. The drugs also have a huge '''anaesthetic sparing effect''', reducing MAC by 50-95%. They also give '''muscle ~~relaxtion~~'''.

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Alpha-2 agonists have a wide range of actions, due to the presence of alpha-2 receptors throughout the body. The actions most useful pharmacologically are '''sedation''', '''anxiolysis''' and '''analgesia'''. The drugs also have a huge '''anaesthetic sparing effect''', reducing MAC by 50-95%. They also give '''muscle relaxation'''.

Other systems affected by alpha-2 agonists include:

* Cardiovascular System

** Post synaptic alpha-2 effects and non-selective action on alpha-1 receptors cause vasoconstriction, hypertension and reflex bradycardia.

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** Pre-synaptic inhibition of noradrenaline release gives a reduced sympathetic outflow. This ~~dexreases~~ heart rate and offsets vasoconstriction.

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** Pre-synaptic inhibition of noradrenaline release gives a reduced sympathetic outflow. This decreases heart rate and offsets vasoconstriction.

* Respiratory System

** The drugs cause mild depression of the respiratory systsem.

** The response to hypercapnoea is reduced.

* Gastrointestinal Tract

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** Alpha-2 agonists cause extreme ~~vomitting~~ in dogs and cats. [[#Xylazine|Xylazine]] is the worst culprit for this.

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** Alpha-2 agonists cause extreme vomiting in dogs and cats. [[#Xylazine|Xylazine]] is the worst culprit for this.

** Huge reductions in gut motility occur following drug administration, as well as decreased salivation and secretion.

* Endocrine System

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