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Drug Therapy of Hypertension - Coggle Diagram
Drug Therapy of Hypertension
Drugs that alter water and sodium balance
Diuretics
Thiazides
inhibits Na+/Cl- symporters in DCT
Hydrochlorothiazide
First line agent
Acts on DCT and smooth muscle cells
increase vasodilation on smooth muscle cells
Loop diuretics
Acts mainly on thick ascending limb of
loop
of henle
Normal detailed mechanism: Na/K/2Cl co-transporters moves Na, K, and Cl ions into principal cells
Na+/K+ ATPase pumps Na+ out into interstitium and K+ into cell
Na+ reabsorbed into blood stream
K+ moves back into lumen of ascending limb
K+ movement allows Ca+ and Mg+ to diffuse back into blood stream
Normal physiology: reabsorption of Mg, Ca, Na, and removal of Cl and K+
sodium and water retention
Loop diuretic effect:
blocks Na+/K+/2Cl contransporter
increased secretion of K+,Na,Ca,Mg,Cl
Inhibits sodium and water retention
decrease BV --> Decrease Preload --> decrease SV/CO --> Decrease BP
Greatest efficacy
Indication
Severe hypertension: extreme volume overload
Blood Volume Overload
Congestive heart failure
Examples
Furosemide
Acts on loop of henle
Blocks Na+/K+/2Cl co-transporters from reabsorption of sodium
Aldosterone antagonists: Potassium sparing diuretics
Spironolactone
blockage of androgens
Adverse effects:
Gynaecomastia
mild efficacy
Mechanism: blocks aldosterone from mineralcorticoid receptors to make sodium reabsorption channels in DCT
increase Na+ and water excretion
Increase potassium reabsorption --> hyperkalamia
Acts on DCT
Contraindications
hypokalaemia (-) K+ (for loop and thiazide)
magnesium depletion (-) Mg+
hyperuricaemia (+) uric acid
gout
ototoxicity (hearing problems) for loop diuretics
hyperlipidimia for thiazide
Hyperkalaemia (+) K+ (for aldosterone antagonists)
Drugs that alter sympathetic nervous system
beta-blockers
Indication
Angina pectoris
Heart attack
Ischemic heart disease
Contraindication
Diabetes Mellitus
Masked hypoglycemia
Normally, symptoms of hypoglycemia is increase in heart rate, however beta-blockers decreases heart rate, hence we won't know if someone has hypoglycemia
Bronchial Asthma
Bronchospasm (non-selective)
Beta 1 blockers
(-) heart rate & (-) renin release
(-) BP
Metoprolol
Beta 2 blockers
(+) bronchoconstriction, (-) glucose in blood
Non-selective beta blockers
Propanolol
Adverse Effects
bradycardia & hypotension
sudden withdrawal leads to severe rebound tachycardia, arrhythmia, hypertension
Alpha 1 blockers
Prazosin
(+) vasodilation in vascular SM & (-) constriction of urinary bladder
Indications
BPH
Contraindications
Postural hypotension (OH)
mixed alpha-beta blockers
Labetolol
Malignant hypertension
Indications
HTN in Pregnancy
pregnant woman with a labcoat
Carvedilol
non-selective B-blocker with alpha-1 antagonist
Indications
Heart failure
Additional vasodilator effects without much change in CO and HR
centrally acting sympathoplegic drugs
Clonidine
Methyldopa
Vasodilators
Nitrates
Mechanism
NO gets produced in endothelial cells in TI
NO moves to SMC in TM
NO activates guanylate cyclase enzyme
GTP --> cGMP
Dilates veins > arteries
vasodilation of veins
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Vasodilation of arteries
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Indications
Angina
prodrug
Contraindications
should not be taken with erectile dysfunction drugs (blocks GMP production)
Hydralazine
Adverse Effects
Drug induced lupus
Indications
Pregnancy HTN via IV
Chronic hypertension via PO
Given with beta blockers to prevent reflex tachycardia
Mechanism
Dilates arteries > veins
(--) afterload
Sodium nitroprusside
indication
Hypertensive emergencies
Mechanism
acts with oxyhemoglobin
produces
NO
guanylate cyclase
GTP -> cGMP
(--) both preload and afterload
cyanide
AE: acute cyanide poisoning
Short-acting
Calcium channel blockers (CCB)
Dihydropyridines
Amlodipine
Nifedipine
bad reflex tachycardia
not suitable for treating angina or arrythmia
medications ending in -
dipine
focuses
more on
vasodilation of
arteries
(not veins)
Side effects
Reflex tachycardia
Peripheral edema
Verapamil
Indications
Angina pectoris
chest pain caused by reduced oxygen supply to myocardium
"to strangle" - "chest"
artheromatous plaques in the coronary arteries
reduces blood flow
reduces oxygen supply to mycardium
chest pain
Treatment
reduce oxygen demand
Reduce heart rate
increase blood supply
Vasodilation
Arrythmias
irregular/fast heart rate
low renin hypertension in African-caribbean origin
Non-dihydropyridines
focuses
more on
reducing
heart
rate
Cardiac depression
Verapamil
Constipation side effects
due to smooth muscle relaxant action (less peristalsis)
more potent
Diltiazem
better vasodilator
good antihypertensive
Side effects
Bradycardia
Contraindications
Pregnancy
Drugs affecting RAAS
ACE inhibitors
medications ending in
-pril
Enalapril
Side effects
dry cough (inhibits breakdown of bradykinin)
more side effects than ARBs
Angiotensin II receptor blockers (ARB)
medications ending in
-sartan
telmisartan (micardis)
Renin inhibitors
Aliskeren
binds to renin to prevent binding with angiotensinogen
Adverse effects
Chronic kidney disease
too much ATII working on vasoconstricting efferent arterioles on kidney results in big increase of glomerulus blood pressure which results in increase of loss of protein, GFR, and thickness of glomerulus basement membrane
Indications
heart failure (decreases TPR, so heart doesnt have to pump as hard)
Acute MI
Contraindications
Pregnancy
induce congenital malformations
