Review/Hypertensive Agents (Cardio Lecture II) Flashcards
What are the CNS neurotransmitters?
epi, norepi, dopamine, serotonin, GABA, acetylcholine
Which are natural catecholamines/endogenous?
epi, norepi, dopamine
Which are synthetic catecholamines?
isoproterenol, dobutamine
Alpha receptors response in order of potency to epi, norepi, and isoproterenol
Norepi > Epi > Isoproterenol
Beta receptors response in order of potency to epi, norepi, and isoproterenol
Isoproterenol > Epi > Norepi
Where are alpha 1 receptors found?
post-synaptic in the vasculature, heart, glands, and gut
What happens when alpha 1 receptors are activated?
vasoconstriction and relaxation of the GI tract
Where are alpha 2 receptors found?
pre-synaptic in peripheral vascular smooth muscle, coronaries, brain
post-synaptic in coronaries, CNS
What happens when pre-synaptic alpha 2 receptors are activated?
inhibition of norepi release and inhibition of sympathetic outflow = decreased BP and HR and decreased CNS activity
What happens when post-synaptic alpha 2 receptors are activated?
constriction and sedation/analgesia
Where are Beta 1 receptors found?
heart primarily (myocardium, SA node, ventricular conduction system, coronaries) and kidney
Activation of the Beta 1 receptors causes
increase in inotropy, chronotropy, myocardial conduction velocity, coronary relaxation, and renin release
Where are Beta 2 receptors found?
lungs primarily
vascular, bronchial, and uterine smooth muscle, smooth muscle in skin, myocardium, coronaries, kidneys, GI tract
Activation of the Beta 2 receptors causes
vasodilation, bronchodilation, uterine relaxation, gluconeogenesis, insulin release, potassium uptake
Ephedrine pharmacokinetics
usually given in 5 mg increments, DOA 15-60 minutes
indirectly deplete catecholamine stores
repeated doses: tachyphylaxis
will increase HR, inotropy, and BP
Phenylephrine pharmacokinetics
DOA 5- 20 minutes
50 - 200 mcg push, 20-100mcg/min infusion
pure alpha = vasoconstriction, reflex bradycardia
can be used in nasal intubation
What kind of receptors are alpha and beta receptors?
GPCRs
Drug classes for HTN that work on the SNS
beta antagonists, alpha 1 antagonists, mixed alpha and beta antagonists, centrally acting alpha 2 agonists
Drug classes for HTN that work on the RAAS
angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, diuretics
Drug classes for HTN that work on the endothelium mediator and/or ion channel modulator
direct vasodilators, calcium channel antagonists, potassium channel opener
According to JNC 8 normal blood pressure is
<120 systolic and <80 diastolic
If you are age 60 or older goal BP is
<150/90 with NO diabetes or kidney disease
What is the first line therapy for HTN (besides lifestyle changes)
thiazide diuretic unless this a compelling indication
Hypertensive urgency
diastolic pressure >120 without evidence of end organ damage
goal: decrease DBP to 100-105 within 24 hours
can use Clonidine
Hypertensive crisis
diastolic pressure >120 with evidence of end organ damage
goal: decrease DBP 100-105 ASAP
can use Nitroprusside, Nitroglycerin, Labetalol, Fenoldapam
Alpha antagonists
bind selectively to alpha receptors and interfere with the ability of catecholamines to cause a response