Hypertension and Antihypertensives

• High blood pressure-Hypertension.
• There is no definite dividing line between normal and high blood pressure, arbitrary values have been established to define hypertension.
• According to JNC VII classification Normal B.P < 120/80 mm of Hg.
• Hypertension stage I-systolic B.P. 140-159 mm of Hg ; Diastolic B.P. 90-99 mm of Hg  Stage II-systolic B.P. > 160 mm of Hg ; Diastolic B.P.>100
• Those lying between 120/80 - 139/89 mm of Hg are in prehypertensive condition.
• Those with B.P 200/140 mm of Hg are called as malignant hypertensives.
• WHO has used 160/95 mm Hg as upper limit of normal.
• Normal B.P. value also depend on the age of patient. 
• Antihypertensive drugs: 

1. ACE INHIBITORS
2. ANGIOTENSIN ANTAGONIST
3. BETA AND ALPHA BLOCKERS
4. DIURETICS
5. CCB

• ACE INHIBITORS-

1.They inhibit the production of Angiotensin II whose main functions are-

 VASOCONSTRICTION(DIRECTLY AND INDIRECTLY BY ENHANCING PRODUCTION OF

 ADRENALINE AND CORTICOSTEROIDS);RAISES B.P.;

 RAISES FORCE OF MYOCARDIAL CONTRACTION AND HEART RATE

 AII acting on chronic basis can cause volume 

 overload(due to sodium and water retention) and increased t.p.r lead
 to ventricular hypertrophy.
 SODIUM RE ABSORPTION AND POTASSIUM LOSS(ALDOSTERONE SECRETION)

2. These Drugs Reduce B.P.;Also reduce preload and afterload;reduces heart rate;increases cardiac output
;improves renal perfusion.
3.Side effects-First dose hypotension;Cough;rashes;proteinuria;Fetopathic and metallic tatse.
4. Preferred drugs for reducing hypertension in HF, in diabetics and in nephropathic patients except those with bilateral renal artery stenosis.
5.Interactions-NSAIDS(indomethacin) can reduce the hypotensive action of these drugs.
6.Uses-For treating Hypertension;CHF;MI;Diabetic nephropathy.
7.Drugs-Enalapril,captopril

• ANGIOTENSIN ANTAGONIST-They block the AT receptors.Due to which Angiotensin can't show its functions.Less side effects,can cause hyperkalemia,hypotension but first dose hypotension is uncommon.Dry cough is not seen.But its fetopathic.

   Drugs-Losartan

• Beta Blockers-

1.They reduce Heart rate,Force of contraction and cardiac output.

2.Can aggravate CHF or can initiate it-They cause increase in Ventricular dimensions.

3.Reduce Cardiac work and oxygen consumption.

4.Initially there is reduction in systolic B.P.(reduced c.o.) and rise in diastolic B.P.(increased T.p.r due to reduced vasodilatation by Beta adrenergic receptors) but on prolonged administration resistance vessels gradually adapt to chronically reduced C.o. and t.p.r decreases leading to fall in both systolic and diastolic B.P.Mild antihypertensives.

5.Decreases renin release.

6.Causes increase in LDL and LDL/HDL ratio

7.Avoided in-Diabetics,Asthmatics,conduction defects,Abnormal lipid profile,CHF,Pregnant ladies

8.However after recovering from CHF,Beta blockers reduce the mortality

9. Preferred in angina,post MI cases.

10.Drugs- Non selective Beta blockers-propanolol

                 Cardio selective(beta1 blockers)-Atenolol,Metoprolol