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