Anti-Hypertensive

• Hypertension


  Increase in blood pressure such that the systolic pressure is >140 mmHg & diastolic pressure is > 90 mm Hg
• Types of hypertension


  • Essential hypertension
  • Secondary hypertension
• Diuretics


  • Promote sodium depletion which decreases extracellular fluid volume (ECFV)
  • Effective as first-line drugs for treating mild hypertension
  • Hydrochlorothiazide is the most frequently prescribed diuretic
  • Can be used alone for recently diagnosed or mild hypertension or it can be used with other antihypertensive drugs
• Sympatholytics (Sympathetic Depressants)


  • Beta-adrenergic blockers
  • Centrally acting alpha2 agonists
  • Alpha-adrenergic blockers
  • Adrenergic neuron blockers (peripherally acting sympatholytics)
  • Alpha1- & beta1-adrenergic blockers
• Beta-Adrenergic Blockers (Nonselective)


  • Inhibit beta1 (heart) & beta2 (bronchial) receptors
  • HR slows, BP decreases secondary to the decrease in HR & bronchoconstriction occurs because of unopposed parasympathetic tone
• Beta-Adrenergic Blockers (Cardioselective)


  Act mainly on the beta1—rather than the beta2—receptors & bronchoconstriction is less likely to occur
• Centrally Acting Alpha2 Agonists


  • Decrease the sympathetic response from the brainstem to the peripheral vessels
  • Reduced peripheral vascular resistance & increased vasodilation
  • Has minimal effects on CO & blood flow to the kidneys
• Alpha-Adrenergic Blockers


  • Block the alpha-adrenergic receptors (alpha blockers) resulting in vasodilation & decreased BP
  • Help maintain the renal blood flow rate
  • Useful in treating hypertension in patients with lipid abnormalities
  • Decrease the VLDL & LDL & increase HDL levels
• Selective Alpha1-Adrenergic Blockers


  • Prazosin
  • Terazosin
  • Doxazosin— used mainly to reduce blood pressure and can be used to treat benign prostatic hypertrophy (BPH)
• Adrenergic Neuron Blockers (Peripherally Acting Sympatholytics)

  • Block norepinephrine release from the sympathetic nerve endings causing a decrease in norepinephrine release that results in a lowering of BP
  • Decrease occurs in both CO & peripheral vascular resistance
  • Reserpine most potent drug to control severe hypertension
• Alpha1- & Beta1-Adrenergic Blockers

  • Blocks both alpha1 & beta1 receptors
  • Blocking alpha1 receptor causes vasodilation which decreases resistance to blood flow
  • Effect on the alpha receptor is stronger than the effect on the beta receptor; BP is lowered & PR is moderately decreased
  • By blocking cardiac beta1 receptor both HR & AV contractility are decreased
• Direct-Acting Arteriolar Vasodilators


  • Act by relaxing the smooth muscles of the blood vessels mainly the arteries causing vasodilation
  • Promote an increase in blood flow to the brain & kidneys with vasodilation blood pressure decreases & sodium & water are retained resulting in peripheral edema
  • Diuretics can be given with a direct-acting vasodilator to decrease the edema
  • Used for moderate to severe (dose related) hypertension
  • Cause little orthostatic hypotension because of minimum dilation of the arterioles
• Direct-Acting Arteriolar Vasodilators

  • Hydralazine
  • Minoxidil
• Angiotensin-Converting Enzyme Inhibitors


  • Benazepril
  • Captopril
  • Enalapril maleate
  • Fosinopril
  • Lisinopril
  • Moexipril
  • Perindopril
  • Quinapril
  • Ramipril
  • Trandolapril
• Angiotensin-Converting Enzyme Inhibitors

  • Mechanism of Action: Inhibit the ACE thereby preventing the conversion of angiotensin I to angiotensin II which is a vasoconstrictor
  • Action leads to decreased AII and decreased aldosterone (causes Na & water retention and excretion of K).
• Angiotensin II Receptor Blockers (ARB)


  • Losartan
  • Valsartan
  • Irbesartan
  • Candesartan
  • Eprosartan
  • Olmesartan
  • Azilsartan
  • Telmisartan
• Angiotensin II Receptor Blockers (ARB)

  • Works by attaching to the Angiotensin II receptors in the vascular smooth muscles and in the adrenal gland
  • Does not prevent formation of AII but blocks the receptor for AII
  • Results in VASODILATION because AII action (constriction) is inhibited and BLOCKAGE of aldosterone release.
• Direct Renin Inhibitors


  • Aliskiren
  • MOA: binds with renin & causes a reduction of angiotensin I, angiotensin II & aldosterone levels
• Calcium Channel Blockers


  • Diphenylalkylamine (verapamil)
  • Benzothiazepine (diltiazem)
  • Dihydropyridines (amlodipine)
• Calcium Channel Blockers


  • MOA: Block the calcium channel in the VSM promoting vasodilation
  • Large central arteries are not as sensitive to calcium blockers as coronary & cerebral arteries & the peripheral vessels
  • Highly protein bound but have a short half-life. Slow-release preparations decrease the frequency of administration