Prazosin Flashcards
Please note that the drug card information is for Educational Use ONLY, and the source is from Carrie Bowman's glossary of drug cards permitted by use of Georgetown NAP students. No permission is given to use these cards for anything other than as a study resource for our program.
What is the trade name for Prazosin?
Minipress
What is the formal drug classification for Prazosin?
Selective POST-synaptic alpha 1 adrenergic Antagonist; Antihypertensive
What are the clinical uses for Prazosin?
- essential hypertension
- to decrease afterload in CHF
- preop prep for patients with pheochromocytoma, who exhibit ST changes on ECG
- Reduces Vasospasm in Raynaud syndrome
- essential hypertension in pts with BPH b/c it reduces prostate size
- Ischemic cardiomyopathy
What receptors does prazosin work on?
Alpha 1
Does prazosin block pre- or post- synaptically?
POST-synaptically (alpha 1 antagonist)
What is the MOA of Prazosin?
Selective post-synaptic alpha 1 adrenergic antagonist resulting in vasodilating effects on both arterial and venous vasculature
Does Prazosin work on the arterial or venous vasculature?
Both, BUT has 1,000 fold > affinity for alpha 1 receptors than for alpha-2 receptors
What does the alpha-1 antagonism of Prazosin cause regarding vascular tone? Is there reflex tachycardia? What happens to venous return and CO?
- Decreases SVR without causing reflex tachycardia or increases in renin activity
- Vascular tone in both resistance and capacitance vessels is decreased, resulting in decreased venous return and CO
Since Prazosin is selective for alpha-1 antagonism, what does this mean regarding alpha-2 receptors and NE release?
It leaves the inhibiting effect of Alpha-2 receptor activity on NE release intact, therefore it is less likely to evoke reflex tachycardia!!!!
What does Prazosin do to the vasoconstrictor effects of NE and Epi?
Antagonizes their effects, thereby causing a decline in Peripheral Vascular Resistance, and venous return to the heart
Tell me about the oral absorption of Prazosin
Has substantial 1st pass effect with oral intake, <60% bioavailability after oral administration
Is Prazosin protein bound?
Highly bound to plasma protein
How is Prazosin metabolized?
Via Demethylation and conjugation in the liver
How is Prazosin eliminated?
Bile and Feces
When does Prazosin take peak effect?
3 hours