Basic Pharmacology of Hypertensive Agents

Physiologically, in both normal and hypertensive individual, Blood pressure maintained by moment to moment regulation of cardiac output and peripheral vascular resistance. exerted 4 anatomic site including arterioles, postcapillary venules (capacitancy vessels), heart and kydney which contributes to maintenance of blood presure by regulating the volume of intravscular fluid.
All antihypertensive agent act at one or more of the 4 anatomic control site and produce their effect by interfering with the normal mechanism of blood pressure regulation. Hypertensive treatment classified by category include the following:

1. Diuretic
   
Which lower blood pressure by depleting the body of sodium and reducing blood volume.

2. Symphatolytic Agent
   
Which lower blood pressure by peripheral vascular resistance, inhibiting cardiac function and increasing venous pooling in capacitance vessel.

3. Direct Vasodilators
   
Which reduce blood pressure by relaxing vascular smooth muscle, thus dilating resistance vessel and to varying degrees increasing capacintance as well.

4. Agent that block production or action of angiotensin
   
Reduce blood pressure by reduce peripheral vascular resistance and (potentially) blood volume. Hypertension is often treated by a combination of 2 or more drugs, each acting by a different mechanism. The rationale of polypharmacy is that each of the drug act on one of a set of interacting, mutually compensatory regulatory mechanisms for maintaining blood pressure.

The following are classification of antihypertensive agent include:

1. Diuretic
   
Low maximal efficacy:
• Indapamide (Lozol)
  
• Phthalimidines
  
• Thiazides
  
High Maximal Efficacy:
• Bumetadine(Bumex)
  
• Ethacrinic acid (Edecrin)
  
• Furosemide (Lasix)
  
Potasium - Sparing:
• Amiloride (MIdamor)
  
• Spironolactone (Aldactone)
  
• Triamterene (Dyrenium)


2. Sympthatolytic Agent
   
Act on central nervous system:
• Clonidine (Catapres)
  
• Guanabenz (Wytensin)
  
• Methyldopa (Aldomet)
  
Act on autonomic ganglia:
• Trimethaphan (Arfonad)
  
Act on postganlionic sympathetic neuron:
• Guanadrel (Hylorel)
  
• Guanethidine(Ismeline)
  
• Monoamine oxidase inhibitors
  
• Reserpine
  
Receptor blockers:
Alpha-Adrenoceptors
• Phenoxybenzamine (Dybenziline)
  
• Phentolamine (Regitine)
  
• Prazosin (Minipress)
  
Beta-Adrenoceptors:
• Atenolol (Tenormin)
  
• Labetalol (Normodin, Trandate)
  
• Metoprolol (Lopressor)
  
• Nadolol (Corgard)
  
• Pindolol (Visken)
  
• Propanolol (Inderal)
  
• Timolol (Blocadren)


3. Vasodilator
   
• Diazoxide (Hyperstat)
  
• Diltiazem (Cardizem)
  
• Hydralazine (Apresoline)
  
• Minoxidil (Loniten)
  
• Nifedipine (Adalat, Procardia)
  
• Nitroprusside (Nipride)
  
• Verapamil (Calan, Isoptine)


4. Inhibitors of renin angiotensin system
   
• Captopril (Capoten)
  
• Enalapril (Vasotec)
  
• Seralasin (Sarenin)
  

Before your decide to choose what anthypertensive drug, better you please to your doctor to choose what Antihypertensive drug match with your Hypertension category, so it will be much benefits and efficacy powerful