Adrenergic Agonists and antagonists Flashcards
Drugs can activate adrenergic receptors by 4 basic mechanisms
Direct receptor binding (most common)
Promotion of NE release
Inhibition of NE reuptake
Inhibition of NE inactivation
Promotion of NE relese
Amphetamines and cocaine, cause NE release in synapses without direct binding. Cocaine also inhibits reuptake
Inhibition of NE reuptake
Blocking NE reuptake causes accumulation in synaptic gap, TCAs and cocaine do this
inhibition of NE inactivation
MAO inhibition
Alpha 1 2 main responses
Vasoconstriction in blood vessels of skin, viscera, mucous membranes
Mydriasis
Alpha 1 to stop bleeding
Topically to prevent bleeding, primarily skin and mucous membranes
Epinephrine
A1 nasal congestion
Results from dilation and engorgement of blood vessels in nasal mucosa, A1 relieve congestion with vasoconstriction
Phenylephrine and pseudoephedrine
A1 with anesthetics
Local anesthetics given with A1 to reduce blood flow to site of anesthetic administration. Done to keep drug local and prolong anesthesia
A1 BP
Can elevate BP in hypotensive pts if can’t give fluid or after fluid
A1 HTN
Cause HTN especially with IV, necrosis if IV lines go interstitial.
Bradycardia A1 agonists can cause a reflex which slow heart