Lecturer
( Adrenergic agonist drugs)
Effects mediated by adrenergic receptor subtypes:
• ɑ1 -receptors: They are excitatory receptors present in smooth muscles
cause contraction of smooth muscles.
e.g smooth muscles of blood vessels → vasoconstriction → ↑ TPR →
hypertension and reflex bradycardia.
On smooth muscles of iris in the Eye→ Active Mydriasis.
Uses of alpha 1 agonist drugs:
1-Epstaxis to stop bleeding in non-hypertensive patients
2-Nasal decongestion (locally)
3- given with local anesthetics
4- Shock
5- As mydriatic agents
Unwanted effects: Increase in the total peripheral resistance (TPR),
hypertension, reflex bradycardia and necrosis of tissue may occur when
applied on peripheral small blood vessels.
Material File