Systemic Effects
Systemic Effects
CNS
  • Sedation and anxiolysis:
    • Effects comparable to normal sleep
    • May be more co-operative and communicative than patients sedated with other drugs
  • Decreases cerebral blood flow, but does not lower intracranial pressure
  • Decreases intraocular pressure
AS
  • Decreases gastric and small bowel motility
  • Acts as an antisialogogue
RS
  • Very minimal respiratory depression
  • At therapeutic doses no change in respiratory rate or PaCO2
CVS
  • Usually exerts biphasic effect on blood pressure:
    • Causes hypotension at lower doses due to predominate effects on imidazoline and alpha-2 receptors
    • Higher doses stimulate peripheral alpha-1 receptors, thereby causing vasoconstriction, which may increase blood pressure
  • May cause a decrease in heart rate (average response 20% decrease)
  • No effect on cardiac contractility, and the cardiac output is well maintained
RenS
  • Acts as a diuretic due to inhibition of ADH