CLASSIFICATION of ANTI-Hypertensive Agents 

Centrally Acting Adrenergic Agents (alpha 2 Agonists)

  • Examples: Clonidine, Guanabenz Acetate. 
  • Mode of Action 

α2 Receptor of Brain

¯ (+)

Acts as Agonist

¯

Decrease sympathetic Outflow

¯

¯HR + ¯SV + Vasso + Arteriolar Dilation

¯

¯BP

Adrenergic System Inhibitors

  1. Adrenergic Neuron Blockers: (Inhibits the storage and Release of neurotransmitters) 

  •     Examples: Reserpine (Depleting The storage); Guanethidine monosulphate (inhibits Neurotransmitter Release) 

  • MOA

Blocks VMAT of storage vesicle

¯

No uptake of NE to storage vesicle

¯

Degradation of NE by MAO

¯

¯ Concentration of NE in Storage vesicle

  1. Adrenergic Receptor Blockers: (Adrenergic Antagonists) 

  •     α1 Antagonist: Prazosin 
  •  Non selective β blockers: Propranolol
  •  Selective β1 blocker: Atenolol 
  • β + α1 blocker: Labetalol 

Vasodilators 

  1. Indirect Acting:

  •     Sympatholytic: Reserpine 
  • Adrenergic (Alpha 1) Blocker: Prazosin 
  • Angiotensin converting enzyme inhibitors: Captopril 
  • Angiotensin II Receptor blockers: Losartan 

  1. Direct Acting

  •     Arterial: Hydralazine 
  • Arterial + Venous: Sodium Nitroprusside 
  • Calcium channel Blockers (CCBs): Amlodipine 
  • K+ channel Opener: Diazoxide 

K+ channel opening

¯

Hyperpolarization of Smooth muscle

¯

Closure of L-type Ca++ channel + inhibition of Ca++ storage and release

¯

¯ - Intracellular Calcium

¯

RELAXATION

Drugs Acting On RAAS System

  • Angiotensin Converting Enzyme inhibitors: Captopril, Lisinopril 
  • Angiotensin II Receptor Blockers: Losartan, Valsartan 
  • Direct Renin Inhibitors: Aliskiren 

Diuretics: 

  • Carbonic Anhydrase inhibitor: Acetazolamide 
  • Osmotic Diuretics: Mannitol 
  • Loop Diuretics (Na+-K+-2Cl- Symporter inhibitors)/ High ceiling: Furosemide  
  • Inhibitors of Na+ Cl- symport (Thiazide and thiazide-like Diuretics): Chlorothiazide 
  • K+ Sparing Diuretics (Inhibitors of renal epithelial Na+ channels): Spironolactone 

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