Epinephrine

(adrenaline)

• Adrenergic agonist
• Potent for alpha and beta receptors
• Cardiovascular effects
• A1: vasoconstriction (cutaneous, visceral, renal; high dose)
• B1: increase contractility, HR, oxygen comsumption = increase CO
• B2: vasodilation (sk mm; low dose) Bronchodilation (powerful, exp. with anaphylaxis or asthma)
• Also see increased Glc, FFA, mydriasis
• Not orally active
• Rapid hypersensitivity reaction reliev, restore cardiac rhythm (av block, cardiac arrest), topical hemostasis

• Adrenergic agonist
• Major NT released by post-ganglionic sympathetic nerves
• Direct alpha and beta agonist
• vasoconstriction and incr BP, decr HR
• Limited use; CV support to maintain BP during shock via A1, B1 effects
• No B2 effect = no bronchodilation

• Adrenergic agonist
• Dose dependent effects
• Low dose: D1 receptor stimulation (Gas receptor), vasodilation, incr renal flow (Na+ excretion), B1 stimulation (+ inotropy)
• High dose: stim vascular A1 (vasoconstriction, decr renal flow)
• Use low dose IV infusion for CHF with compromised renal function; short term only for stabilization

• Non-selective beta adrenergic agonist
• B1>B2 & A1 action
• CV effects: Incr contractility with minimal HR changes (B1)
• Minimal BP change
• Positive inotrope during CHF; short term
• Can get unwanted/excess beta stimulation, incr HR (B1) when used as a bronchodilator (B2)

Albuterol 

(salbutamol)

• Selective B2 adrenergic agonist
• For bronchospasm in dogs, cats, horses

• Selective B2 adrenergic agonist
• Used for allergic bronchitis, recurrent airway obstruction (heaves)

• Selective A1 adrenergic agonist
• Decongestant,  vasopressor
• Toxicity with excess A1 activity (hypertension)

• Selective A2 adrenergic agonist
• CNS depression
• Widely used as an adjunct for sedation, anesthesia, analgesia
• Relatively high safety profile
• Light anesthesia by iteself
• Allows for lower dose of other anesthetic and analgesic agents with lower safety profiles
• Decrease BP

• Non-competitive antagonist; direct acting
• Blocks A1, A2 irreversibly
• Reduces urethral sphincter tone; manage blockage

• Competitive antagonist; direct acting
• Blocks A1, A2 reversibly
• Reduces urethral sphincter tone; manage blockage

• Selective A1 adrenergic antagonist
• Arterial and venous vasodilation (block Epi, NE)
• Antihypertensive in CHF to reduce pre and afterload
• Less reflexive tachycardia than other vasodilators
•  

• Selective A2 adrenergic antagonist; competitive
• Rapid rversal of sedative and analgesic effects of medetomidine: 5x dose of medetomidine
• Minimal risk for relapse to sedation
• Increase SANS activity; don't use with heart or respiratory disease

• Nonselective B adrenergic antagonist
• Equal affinity for B1, B2
• Decreases CO (B1)
• antiarrhythmic action from decr SANS stimulation
• Limited use because of B2 blockade and avalability of B1 selective agents

• Nonselective B adrenergic antagonist
• Ocular use to decrease aqueous humor production during glaucoma

• Selective B1 adrenergic antagonist
• Selectivity is relative; blocks B2 at higher doses
• Decreased HR, CO, oxygen demand, BP
• Excessive sympathetic stimulation is proarrythmogenic, decrease arrhythmias
• Useful for Feline HCM possibly