Clonidine Flashcards
1
Q
action
A
- centrally acting alpha 2 agonist
- decreased sympathetic outflow from CNS
- Dec in BP, HR< CO
2
Q
indication
A
- essential hypertension
- diagnose pheochromcytoma–dec plasma concentrations of catecholamines in nl pts, but not those with pheo
- supresses sxs of narcotic withdrawal
- dec MAC, fent requirement–c/w dec in sympathetic outflow
- intrathecal when tolerance to morphine has developed
- epidurally
3
Q
side effect
A
-rebound hypertension–assoc with large inc in catecholamines
4
Q
receptors affected
A
- descending medullospinal noradrenergic pathway modulating spinal nociceptive processing
- receptors are from dorsal horn, where they inhibit neurotransmitters like substance P
5
Q
epidural clonidine
A
- epidural clonidine–better, longer analgesia compared to subQ morphine
- does not reduce sensory or motor block
- associated with hypotension, bradycardia–inhibition of preganglionic sympathetic fibers
6
Q
methyldopa
A
- a2 agonist
- stimulates a2 receptors in hypothalamus–decreasing sympathetic outflow from brain
7
Q
clonidine
A
- stimulates a2 neurons in medullary vasomotor center
- decreases sympathetic outflow from CNS
8
Q
Reserveres
A
- interferes with NE reuptake into nerve terminal storage vesicles
- depletion of NE
9
Q
guanethidine
A
- enters storage granules and interferes with NE release from storage vesicles
- TCA and ephedrine block this, decreasing effectiveness of the drugs