Hypertension and Heart failure Flashcards
How is peripheral vascular resistance controlled by calcium
- Increased calcium> vasoconstriction> raises BP
- Decreased calcium> vasodilation> Decreases BP
Hypertension increases the risk of
- stroke
- Myocardial infarction
- Congestive heart failure
- renal failure
Preeclampsia
Complications associated with hypertension during pregnancy
Eclampsia
Preeclampsia with seizures
RAAS
Hormone system that regulates blood pressure and fluid balance
Factors that initiate RAAS through renin release
- Decrease renal perfusion
- Sympathetic nerve stimulation(beta1 agonists)
- Transmitters: catecholamine, prostaglandin I2 and E2
- Reduced Na ad Cl conc at distal tubule
Factors that prevent activation of RAAS
- neg feedback through angiotensin II and increased renal perfusion
- Natriuretic peptide
Action of RAAS to increase BP
- induced renin release in juxtaglomerular cells of kidney
- Renin cleaves angiotensinogen> angiotensin I
- ACE converts angiotensin I> angiotensin II
- Angiotensin II activates AT1 receptors to increase BP
Effects Aldosterone and vasopressin
- aldosterone increases salt retention> upregulates Na+ channels in collecting ducts
- vasopressin increases water retention> increases Na+ reabsorption across ascending loop of Henle
Antihypertensives
- Direct-acting: CCB, Hydralazine
- Indirect-acting: Sympatholytics, ACE-I, ARB, centrally-acting drugs
- diuretics
ACE-I drugs and their MOA
- Captopril, enalapril, perindopril
- Inhibits ACE mediated conversion of AngI to Ang II. Prevents RAAS activation and subsequent downstream effects
ACE-I side effects and contraindication
- Angioedema, hypotension, photosensitivity, nephrotoxicity
- pregnancy, renal stenosis
Angiotensin II receptor blocker drugs and their MOA
- Candesartan, losartan, valsartan
- Reversibly competitively bind to AR increases secretion of aldosterone and vasopressin leading water and sodium retention> vasodilation
ARB side effects and contraindications
- coughing, hypotension, photosensitivity, nephrotoxicity
- renal stenosis, pregnancy
CCB drugs and their MOA
- Diltiazem, amlodipine, nifedipine, verapamil
- Blocker bind to L-type Ca+ channels> inhibiting opening of channels> reduces Ca+ influx> vasodilation and neg inotropy of heart
CCB side effects and contraindications
- Flushing, headache, tachycardia, hypotension, constipation
- heart failure> worsening of cardiac function
Adrenergic blocker drugs and their MOA
- Atenolol(beta1), propranolol(beta), Carvedilol, labetalol(alpha/beta)
- Beta blockers decreases renin secretion
Centrally-acting vasodilator drugs and their MOA
- alpha-Methyldopa
- Potent agonist of presynaptic alph2-adrenergic receptors> prevents release of NA> inhibits synaptic outflow
Direct-acting vasodilator drug and their MOA
- hydralazine
- Arteriolar vasodilation
Indications and side effects of direct-acting vasodilators
- Gestational hypertension
- oedema, reflex tachycardia, thrombocytopaenia
Dangerous interactions with antihypertensives
- NSAID> increased BP> renal failure
Treatment for hypertensive emergency
- IV labetalol
- IV nitroprusside
- IV nitroglycerin
Causes for heart failure
Hypertension, obesity, sleep apnoea, myocardial infarction
Systolic heart failure
Myocardium too weak to pup blood due to large ventricles and thin myocardial walls
