L 33-35 Flashcards
4 Main categories of drugs used for hypertension
1) Diuretics
2) Drugs affecting SNS (sympatholytics): alpha-2 agonists, alpha-1 blockers, beta blockers
3) Vasodilators: NO, K+ channel, D-1 receptor, Ca channel
4) RAAS inhibitors: ACEI, ARB’s (ang receptor blockers), Renin inhibitor
Anti-hypertension drugs in diuretics category
Hydrochlorothiazide (prototype)
Furosamide
Anti-hypertension drugs in sympatholytic category that are alpha-2 agonists
Clonidine
Methyldopa
Anti-hypertension drugs in sympatholytic category that are alpha-1 blockers
Prazosin
Doxazosin
Terazosin
Anti-hypertension drugs in in sympatholytic category that er beta-blockers
Propranolol, Timolol, Nadolol (non-specific)
Metoprolol, Atenolol, Nebivolol (beta-1 specific)
Acebutolol (beta-1, with ISA)
Pindolol (with ISA)
Carvedilol (alpha and beta blocker)
Anti-hypertension drugs in vasodilator category that act through NO
Hydralazine
Sodium nitroprusside
Anti-hypertension drugs in vasodilator category that open K+ channels
Minoxidil
Diazoxide
Anti-hypertension drugs in vasodilator category that stimulate D-1 receptors
Fenoldopam
Anti-hypertension drugs in vasodilator category that are Ca channel blockers
Verapamil
Diltiazem
Nifedipine
Anti-hypertension drugs in RAAS inhibitor category
Captopril (-pril’s)–ACE inhibitors
Losartan (-sartan’s)–ARB’s=angiotensin receptor blockers
Aliskiren–Renin inhibitor
Specific causes of Hypertension
Renal artery constriction Coarctation of aorta Pheochromocytoma Cushing's disease Primary aldosteronism
Common complications of hypertension
CAD
Stroke
Renal failure
Sympathetic receptor that stimulates renin secretion
beta-1
4 ways SNS affects blood pressure
1) Resistance arterioles
2) Capacitance venules
3) Heart output
4) Renin secretion
All increase BP, this is why sympatholytics are used for HT
Explain Baroreceptor reflex
1) Baroreceptor in carotid sinus senses MAP
2) Signal sent to nucleus of tractus solitarius onto inhibitory neurons that fire into the vasomotor center
3) Vasomotor center sends signal down spine to autonomic ganglia
4) Autonomic Ganglia send motor fibers out to sympathetic nerve endings that act on alpha/beta receptors
Increased baroreceptor firing => inhibition of vasomotor center=> decreases SNS tone=> decreased BP
All happens within 3-4 beats
What should be done before initiating drug therapy for HT?
Life-style modification before drugs: Exercise Lose weight Limit dietary salt, fat, alcohol Stop smoking
Why must BP be dropped slowly, especially in elderly?
To prevent damage to vital organs.
In elderly, coronary perfusion may become inadequate=>morbidity and mortality
In patients over 50, which part of BP is more significant in terms of cardiac risk factor?
Systolic matters more than diastolic in persons over 50
What is initial drug treatment for all HT patients, and what is the most significant contraindication?
Thiazides are first line for most patients
Except for those with a sulfa allergy
Or those with high-risk conditions like: DM, kidney disease, ischemic heart dis., HF, cerebrovascular disease.
Thiazide mech of action to lower BP
Thiazides act in distal convoluted tubule to block Na/Cl co-transport.
Dec Na reabsorption=>decrease in blood volume and decrease in CO=>dec BP
Over time, dec Na in smooth muscle cells=>dec muscle sensitivity to vasopressors. Also with time cause K channel opening=>vasodilation
Indapamide
Thiazide type diuretic that also is a direct vasodilator
Common side-effects of thiazide diuretics used to reduce BP
Impotence Gout–competes for transporter in kidney Hypokalemia Muscle cramps Dec insulin production=> increased plasma lipids, reduced glucose tolerance
In what populations are Thiazides more effective?
African-American
Elderly
Name 2 main centrally acting Sympatholytics
Clonidine
Methyldopa
