Cardio- Antihypertensives Flashcards
(28 cards)
what are the components of the blood pressure formula (BP)?
CO x PVR
what does the term baroreceptors refer to, and where specifically in the cardiovascular system does it apply?
moment to moment regulation of blood pressure.
in carotid artery and aorte- it monitors the stretch of the blood vessles.
how do baroreceptors react to an increase in stretch of blood vessels, as well as a contraction of blood vessels?
^ stretch -> baroreceptor stim. -> ˇ in SNS activity.
ˇ stretch -> ˇbaroreceptor activity -> ˆ SNS activity
how do kidneys control long-term blood pressure in kidneys* and what hormone is responsible for this mechanism?
when BP ˇ -> ˆ [renin]-> ^[angiotensin 2] -> constricts vessels -> ^ [aldosterone] -> ^Na+ retention and ^ in BLOOD VOLUME*
what are the normal levels for BP, as well as the hypertensive, and pre hypertensive?
optimal 115/75
hyper >140/90
pre 120/80
hows does Clonidine regulate BP?
CNS adrenergic neurons regulat BP, and there are alpha2 receptors on adrenergic nerver terminals in CNS. Clonidine is an alpha 2 agonist.
what is the clonidine mechanism in the body?
clonidine -> ˇ NE in CNS -> ˇ SNS and ˆ PSNS activity = ˇ CO & PVR.
what is the toxicity of clonidine?
CNS effects= sedation & impaired concentration
What is the effect of Beta Blockers on BP? (both in heat and kidney)
block of beta1 receptors in heart = ˇCO
block of beta1 receptors in juxta-glomerular region of kidney -> ˇ renin release = ˇPVR
name a non-selective beta blocker for BP, and name its toxicity.
propranolol,
toxicities associated with beta2 blockade (-asthma)
name a selective beta1 blocker.
Metoprolol
what are alpha block (in relation to BP), and their toxicity?
a selective alpha1 drug is prazosin. they block alpha 1 receptors in arterioles and venules. salt and water retention occurs, usually pairs with diuretics or beta blockers. and the toxicity is rare : dizziness, palpitations.
what are vasodilators, ie. what do they do?
they relax smooth muscles of arterioles, which ˇ PVR & ˇBP, some also relax veins. They work best in combination with other antihypertensives that oppose compensatory responses.
name a vasodilator that is a nitric oxide donor.
Sodium nitroprusside given IV for hypertensive emergencies. Its fact acting it dilates arterial and venous vessels. its toxicitiesL hypotension, cyanide accumulation
name a vasodilator that is a calcium channel blocker.
Verapamil used for long-term & emergency inhibits Ca2+ influx -> relaxation ->vasodilation also inhibits cardiac Ca2+ channels toxicity: bradycardia
what is ACE?
Angiotensin converting enzyme
it converts angiotensin 1 to angiotensin 2 by inactivation bradykinin
what is angiotensin 2, and what is its purpose
its a potent vasoconstrictor, and ˆ secretion of aldosterone and ADH
what is bradykinin?
its a vasodilator that increases [NO] and results in relaxation of the muscle.
what is aldosterone?
it increases Na+ reabsorption in distal tubules and collecting tubules (H2O will follow- osmosis)
ADH= antidiuretic hormone (vasopressin) increases the permeability of collecting ducts in kidney and increases the H2O reabsorption.
name an ACE inhibitor and its side effects.
Enalapril: prodrug that metabolized to active drug.
S.E.: cough, hypotension, dizziness, heachache
name an AT1 receptor Blocker (ARB). and its side effects
Losartan: effectiveness similar to ACE inhibitors, parent drug and metabolite active
S.E.: same as ACE inhibitor.
what is a diuretic?
decreases BP by depleting body of Na+
what diuretic could be use for mild-moderate hypertension? and how does it work?
hydrochlorothiazide
inhibits NaCL transport in distal convoluted tubule.
inexpensice and effective
toxicities: hypokalemia, gout, hyponatremia
what diuretic should be used for more powerful hypertensions? and gow dies it work?
Furosemide
inhibits co-transporter of Na+, K+ and Cl- in loop of henle.
rapid and short acting
toxicities: can cause dose dependent ontotoxicity (hearing loss)
