Antihypertensives
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Antihypertensives

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All about antihypertensives.

All about antihypertensives.
Easy mechanism of action with important drugs of every classification.

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Antihypertensives Antihypertensives Presentation Transcript

  • Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke and myocardial infarction.
  • Classes Diuretics Adrenergic receptor antagonists Benzodiazepines Calcium channel blockers Renin Inhibitors ACE inhibitors Angiotensin II receptor antagonists Aldosterone receptor antagonists Vasodilators α2 agonists Endothelin receptor blockers
  • • Hydrochlorothiazide, a popular thiazide diuretic • Loop diuretics: –Furosemide • Thiazide diuretics: • Thiazide-like diuretics: • Potassium-sparing diuretics: –spironolactone Diuretics
  • Action Act on kidney Relax blood vessel walls Remove more sodium and water from water Lower blood pressure
  • • Thiazide diuretics are recommended as the first line of treatment for high blood pressure. They are usually recommended as one of at least two medicines to control high blood pressure. • Loop diuretics are prescribed for people who also have heart failure, kidney problems, or swelling in their legs (edema)
  • • Furosemide, like other loop diuretics, acts by inhibiting NKCC2, the luminal Na-K-2Cl symporter in the thick ascending limb of the loop of Henle. • By inhibiting the transporter, the loop diuretics reduce the reabsorption of NaCl and also diminish the lumen- positive potential that derives from K+ recycling
  • • Spironolactone is used primarily to treat heart failure, edematous conditions such as nephrotic syndrome or ascites in patients with liver disease, essential hypertension, hypokalemia. • spironolactone is only a weak diuretic because it primarily targets the distal nephron (collecting tubule), where only small amounts of sodium are reabsorbed, but it can be combined with other diuretics to increase efficacy. • The antihypertensive effect of spironolactone may exceed that of complex combined regimens of other antihypertensives since it targets the primary cause of the elevated blood pressure.
  • Adrenergic receptor antagonists • Beta blockers – atenolol – Metoprolol • Alpha blockers • Mixed Alpha + Beta blockers: – labetalol
  • Beta Blockers Inhibits the effect of nor epinephrine and epinephrine And lessens the feedback mechanism G protein receptor kinase inhibits receptor activity Increase in cyclic Adenosine monophosphate Improves contractions Decrease heart rate, Calcium entry into failing myocytes
  • Labetalol combines both selective, competitive, alpha-1-adrenergic blocking and nonselective, competitive, beta-adrenergic blocking activity in a single substance. Stimulation of beta receptors within myocardium Stimulation of alpha receptors within vascular smooth muscles Decrease in systemic arterial blood pressure and systemic vascular resistance Without a reduction in heart rate, cardiac output or stroke volume.
  • Benzodiazepines • They work as an agonist of the GABA-a receptors in the brain, thus slowing down neurotransmission and dilating blood vessels. • benzodiazepines inhibit the re-uptake of a nucleoside chemical called Adenosine, which serves as an inhibitory chemical mentioned above. It also serves as a coronary vasodilator, allowing the cardiac muscle to relax and dilating cardiac arteries.
  • Calcium channel blockers • block the entry of calcium into muscle cells in artery walls. Peripheral arterial dilatation Stimulation of renin and formation of angiotensin Decrease systemic vascular resistance Decrease in blood pressure Amlodipine Nifedipine Diltiazem
  • Diltiazem • Diltiazem is a potent vasodilator, increasing blood flow and variably decreasing the heart rate via strong depression of A-V node conduction. • Because of its negative inotropic effect, diltiazem causes a modest decrease in heart muscle contractility and reduces myocardium oxygen consumption. • Its negative chronotropic effect results in a modest lowering of heart rate, due to slowing of the sinoatrial node. It results in reduced myocardium oxygen consumption. • Because of its negative dromotropic effect, conduction through the AV (atrioventricular) node is slowed, which increases the time needed for each beat. This results in reduced myocardium oxygen consumption
  • Renin Inhibitors Renin inhibitors bind to the active site of renin and inhibit the binding of renin to angiotensinogen. renin inhibitors prevent the formation of Ang I and Ang II A reduction in Ang II levels or blockade of angiotensin receptors suppress the feedback loop increased plasma renin concentrations (PRC) and plasma renin activity(PRA)
  • ACE Inhibitors Blocks the conversion of angiotensin I to angiotensin II Lower arteriolar resistance Increase venous capacity Normally Angiotensin II causes vasoconstriction and hence hypertension. Decrease cardiac output Increase excretion of sodium in the urine Stimulates adrenal gland to release aldosterone which causes sodium retention and hence increase in blood pressure. Stimulates post. Pituitary to release vasopressin which also increases water retention With ACE inhibitors, the production of angiotensin II is decreased, leading to decreased blood pressure. Captopril Enalapril Ramipril
  • Angiotensin II receptor antagonists These substances are AT1-receptor antagonists; that is, they block the activation of angiotensin II AT1 receptors. vasodilatation. reduces secretion of vasopressin. reduces production and secretion of aldosterone. The combined effect reduces blood pressure. olmesart an telmisart
  • Vasodilators • Vasodilators act directly on the smooth muscle of arteries to relax their walls so blood can move more easily through them; only used in hypertensive emergencies. Vasodilatation works to decrease TPR and blood pressure through relaxation of smooth muscle cells in the tunica media layer of large arteries and smaller arterioles. TPR: total peripheral resistance
  • α2 agonists Stimulate alpha receptors in the brain Open peripheral arteries For treating hypertension, these drugs are usually administered in combination with a diuretic. Adverse effects of this class of drugs include sedation, drying of the nasal mucosa and rebound hypertension.
  • Endothelin receptor blockers By blocking this interaction, bosentan decreases pulmonary vascular resistance. Under normal conditions, endothelin-1 binding of ET-A or ET-B receptors causes constriction of the pulmonary blood vessels. Bosentan is a competitive antagonist of endothelin-1 at the endothelin-A (ET-A) and endothelin-B (ET-B) receptors.
  • Side Effects of Diuretics Potassium-sparing diuretics retain the potassium that other diuretics cause the body to excrete. Common side effects of these diuretics include nausea, headache and stomach upset. The most common side effect of loop diuretics, such as Lasix, is hypokalemia, or low potassium. Other side effects include dry mouth, weakness , diarrhea and headache. difficulty urinating, gout, a nd hives are severe side effects and should be addressed immediately. Thiazide diuretics can cause orthostatic hypotension.
  • Side Effects of ACE Inhibitors Common side effects of ACE inhibitors are diarrhea, headache and joint pain. Fever and chills, trouble breathing or jaundice requires immediate attention.
  • May include fatigue, dizziness and weakness. Side Effects of Beta Blockers
  • Regular check-Up