Miscellaneous Drugs & Ganglionic Blockers Flashcards
What are the Alpha-2 Agonists?
- Clonidine
- GuanaBenz
- Guanfacine
- Methyldopa but its a prodrug
What happens with chronic activation of Alpha-2 and Beta-2 receptors?
Down regulation and loss of sensitivity to the Alpha-2 Agonist.
What complex/compund blocks the GRKs receptor complex formation?
Spinophilin
What happens when Beta-arrestins bind to phosphorylated Alpha-2 adrenoceptors?
This activates B-arr dependent signaling, these processes desensitize G protein signaling
What is the end result of B-arr binding?
The initiation of Alpha-2 adrenoceptor endocytosis
What are the Alpha-2 herteroreceptors?
Expression of the Alpha-2 receptor on Non-cholinergic tissue (Also presynaptic)
Where do Alpha agonist have most of their activity (Bradycardia, hypotension, sedation etc)
Alpha-2 heteroreceptors
How are the Bradycardia and hypotension achieved by the Alpha-2 agonists?
By activation of the parasympathetics especially the Vagal nerve system
What are the 2 functions of Alpha-2 Autoreceptors?
- Limit release of Norepi from sypathetic nerves
2. Limit release of Epi from Adrenal Chromaffin cells at rest
What is a requirement for an Alpha-2 agonist to be able to clinically lower BP?
Must cross the Blood Brain Barrier
What are the clinical effects of Alpha-2 Agonists?
- Parelled and Balanced drop in PVR and Systolic and Diastolic BP
- Withdrawal of SNS tone
- NO REFLEX TACHYCARDIA
- Decrease in Plasma renin activity
- Regression of Left Ventricular Hypertrophy
What are some of the Benefits of Alpha-2 agonists?
- Useful in Blocking reflex Tachycardia
2. No meaningful effect upon blood glucose or Lung function
Which two Alpha-Agonists are available by IV?
Clonidine and Methyldopa
Clonidine transdermal Patch
Which Alpha-2 Agonist has the Longes Half life?
Methyldopa Longest & Guanfacine Shortest
What spplement would chelate alphamethyldopa?
Iron supplements, suggested 2 hour gap between consumptions
