drugs

• DILATION


  1. NO/nitrates → inc. cGMP → dephosphorylates MLC → prevents interaction of MLC + actin

  2. CCB → blocks Ca → no contraction

  3. Beta-2 agonist → activates AC → inc. cAMP → inactivates MLCK

  4. K+ channel openers → hyperpolarization → closes Ca channel
• FOR ANGINA


  DECREASE O2 DEMAND
• Beta blockers are not vasodilators
• Beta blockers


  1. Dec. contractility, HR, BP, renin secretion → dec. wall stress → dec. O2 demand

  2. Inhibits beta 1 receptors in cardiac monocytes, inhibits SA/AV node

  3. Decreased HR → inc. diastolic filling time → inc. O2 supply

  4. Preload also increases → dec. CPP (mild)
• Nitrates


  Potent vein dilators (veins more sensitive)
• effect of nitrates on veins

  Relax vein → inc. vein capacitance → dec. venous return → dec. preload → dec. O2 demand
• effect of nitrates on Arteries

  Dec. arterial pressure → dec. afterload → dec. wall stress → dec. O2 demand
• CCB


  • DHP → vasodilators (arteries/arterioles more sensitive than veins)
  • Non-DHP → dec. contractility & HR → dec. O2 demand
  • Dec. AV conductance
• ANTIHYPERTENSIVES


  • Diuretics
  • Alpha 2 RA (methyldopa, clonidine, guanfacine)
  • Ganglion blocking agents (mecamylamine HCl/vecamyl)
  • Beta blockers (-olol)
  • Alpha adrenoreceptor blocking agents
  • Direct vasodilators
  • CCB
• Diuretics


  Alter Na & water balance → Lower BP by depleting Na & reducing blood volume
• Alpha 2 RA


  Agonist at presynaptic alpha 2 receptor → negative feedback to synaptic vessels → dec. NE release → dec. vascular tone → lower BP
• Ganglion blocking agents


  Inhibits nicotinic receptors → prevents ACh response (sudden hypotension)
• Beta blockers


  • Cardioselective (block beta 1 receptors only) → dec. contractility & renin secretion
  • Nebivolol: inc. NO → vasodilatory
  • Nonselective, do not block alpha
  • Sotalol also blocks K+ channels → prevents depolarization
• Alpha adrenoreceptor blocking agents


  • Alpha 1 blockers are better (we don't want to block alpha 2): prazosin, terazosin, doxazosin
  • Nonselective inc. NE release
• Direct vasodilators


  1. Hydralazine → bind to endothelium receptors of arterioles → inc. NO → inc. cGMP → dec. BP

  2. Fenoldopam → selective dopamine 1 receptor agonist → activate AC → inc. cAMP → inactivate MLCK → dec. BP

  3. Minoxidil & Diazoxide → open K+ channel → hyperpolarization → vasorelaxation
• CCB


  • DHP → vasodilators → reduce peripheral vascular resistance → dec. BP
  • Non-DHP → dec. contractility & HR → dec. SV, CO → dec. BP