Hypertension, commonly known as high blood pressure, is defined as persistently elevated pressure in the arteries, categorized into primary (90-95% of cases without known cause) and secondary hypertension (5-10% with identifiable causes). It has several stages and can lead to serious complications, including heart attack and stroke. Various anti-hypertensive medications are available, including ACE inhibitors, diuretics, and beta-blockers, each with distinct mechanisms of action to manage blood pressure.

1. HYPERTENSION
Neda Fatima
M.Pharm (Pharmacology)
Amity University, Lucknow

2. DEFINATION
Hypertension: Hypertension is also known as high blood pressure, in which the blood pressure in the
artery is persistently elevated.
Blood Pressure: The blood pressure is the pressure which is exerted by circulating blood on artery walls.
Types of Blood Pressure
There are mainly two types of blood pressure i.e.
a. Systolic Blood Pressure
b. Diastolic Blood Pressure
a. Systolic Blood Pressure: It is specifically the maximum arterial pressure during contraction of heart. The systolic
blood pressure (SBS) will be more than or equal of 140 mmHg.
b. Diastolic Blood Pressure: Diastolic blood pressure, refers to the lowest pressure within the arterial blood stream
due to expansion of heart. The diastolic blood pressure (DBP) will be more than or equal of 90 mmHg.
Types of Hypertension:
1. Primary hypertension
2. Secondary hypertension

3. 1. Primary hypertension: Primary hypertension also known as essential hypertension or idiopathic
hypertension) is the form of hypertension , it does not have a known cause approximately 90 to 95% of
have primary hypertension.
Etiology:
• Age
• Alcohol
• Cigarette
• Diabetes mellitus
• Hyperlipidemia
2. Secondary hypertension: The secondary hypertension have a known cause approximately 5 to 10% Patient
have secondary hypertension.
Etiology:
• Obstructive sleep apnea
• Kidney problem
• Adrenal gland tumors
• Thyroid problems
• Certain medication such as birth control pills

4. • Cold remedies
• Decongestants
• Over the counter pain relivers
• Some prescription drugs
• Illegal drugs such as Cocaine and Amphetamine
Stages of Hypertension:
Stages Systolic mmHg Diastolic mmHg
Stage 1 130 – 139 80 – 89
Stage 2. 140 or higher 90 or higher
Stage 3 Higher than 180 Higher than 120

5. Pathogenesis
1. Genetics: Single gene mutation may lead to the development of high blood pressure.
2. Autonomic nervous system: The two major hormone affect the autonomic nervous
system i.e. epinephrine or non- epinephrine which affect the normal parameter in our
such as heart rate, vesicular elasticity, vesicular resistance ,cardiac output etc. if any
disturbance takes place in the autonomic nervous system which may increase the blood
pressure.
3. Renin Angiotensin aldosterone system (RAAS): The Renin - Angiotensin – Aldosterone
system is a hormone system within the body that is essential for the regulation of blood
pressure and fluid balance. The angiotensin II act at hypothalamus to stimulate the sensation
of thirst, resulting in an increase in fluid consumption. This helps to raise the circulating
and in turn, blood pressure.
4. Endothelial dysfunctioning: The endothelium of the blood vessels help to produce more
substances which affect the blood flow such as Nitric oxide and Endothelin help to regulate
vesicular tone and blood pressure.

6. If any disturbance takes place in Endothelium then the secretion of Nitric oxide and Endothelin
affect the blood pressure due to which the blood vessels unable to dilate.
Complications:
• Heart attack or stroke
• Aneurysm
• Heart failure
• Dementia
• Weak and narrow blood vessels in the kidney

7. Anti-Hypertensive
The agents or drugs which are used in the treatment of hypertension is knowns as anti hypertensive
drugs.
Classification:
1. ACE Inhibitors Captopril, enalapril, lisinopril, perindopril, ramipril
2. Angiotensin antagonist: Losartan, irbesartan, candesartan
3. Calcium channel blocker: Verapamil, diltiazem, nifedipine, felodipine, amlodipine, lacidipine.
4. Diuretics:
a. Thiazide: Hydrochlorothiazide, chlorthalidone, indapamide
b. High ceiling: Furosemide
c. Potassium sparing: Spironolactone, amiloride

8. 5. Beta – Adrenergic Blockers: Propranolol, metoprolol, atenolol
6. Alpha + beta adrenergic blockers: Labetalol, carvedilol
7. Alpha – adrenergic blockers: Prazosin, terazosin, phentolamine
8. Central sympatholytic: Clonidine, methyldopa
9. Vasodilators: Hydralazine, minoxidil sodium
1. Angiotensin converting enzyme: These drugs helps peoples with systolic heart failure, ACE
inhibitors are a type of vasodilators, a drugs that widen blood vessels to lower blood pressure.
Example: Captopril. Enalapril, lisinopril

9. Angiotensin
Renin
ACE inhibitors Angiotensin – I (Ag –I )
Block ACE enzyme
Angiotensin –II (Ag- II)
Aldosterone Vasoconstriction
Na + and H2O retention B.P Blood pressure
Blood volume
Blood pressure

10. 2. Angiotensin - II receptor blocker: These may be an alternative for people who can not
Tolerate ACE inhibitors.
For example: Losartan, valsartan
Angiotensin
Angiotensin – I (Ag –I)
Angiotensin II (Ag- II)
Aldosterone Vasoconstriction

11. Na+ and H2O retention Blood volume
Blood volume
Blood pressure
Blood pressure
Calcium channel blockers: The calcium channel blocker reduces electrical conduction within
the heart, decrease the force of contraction after the medication that relax the blood vessels and
increase the supply of blood and oxygen to the heart while reducing the workload.
For example: Amlodipine, diltiazem, felodipine, isradipine, verapamil.

12. a. Amlodipine: The amlodipine inhibits the transmembrane influx of calcium ions into vascular smooth
muscles and cardiac muscles , reducing vesicular resistance.
b. Diltiazem: It inhibits calcium movement across cell membrane of cardiac and smooth muscles causing
vasodilation decrease heart rate and contractility, slow SA and AV nodes.
c. Verapamil: Verapamil inhibits the calcium ion and possibly sodium ion influx through slow channels into
conductive and contractile myocardial cell and vascular smooth muscle cells.
Mechanism of action of calcium channel blocker: The calcium channel blocker bind to the calcium
channel and inhibit the calcium channel . The inhibition of calcium channel cause no entry of calcium into
the heart that leads to the dilation of arteries and decreases blood pressure.
4. Diuretics: Diuretics are the agents that increase the production of urine. Diuretics also called water pills
which are commonly used in the treatment of high blood pressure.
For example: a. Thiazide: Hydrochlorothiazide, chlorthalidone, indapamide

13. a. High ceiling: Furosemide
b. Potassium sparing: Spironolactone, amiloride
Mechanism of action of High ceiling (Loop diuretics)

14. Loop diuretic (high ceiling) block the Na + /k+ / 2Cl cotransporter on the thick ascending loop of
inlet result in increase retention of Na+ / 2Cl.
Mechanism of action of Thiazide diuretics:

15. Thiazide diuretics block the Na + / Cl- symport on the distal convoluted tubule ( site -3) result in
increase the retention of Na+ / Cl- in the convoluted tubule.
Mechanism of action of Potassium sparing:

16. Amiloride inhibit the Na+ channel on the collecting tubule that lead to increase the excretion of
Na+ in the urine.
5. Mechanism of action of Beta – Adrenergic blockers: Beta blocker bind to the beta -1
on heart (SA node) and inhibits the beta 1 receptor that leads to decrease in the blood pressure.
Beta blocker bind to the receptor in kidney (JG cell) and inhibit the release of renin causing no
conversion to angiotensinogen into angiotensin I and decrease blood pressure.
For example: Atenolol, metoprolol, propranolol etc.
6. Mechanism of action of alpha + beta blocker: Beta + alpha blocker bind to the beta +
receptor and inhibit the alpha + beta receptors due to the inhibition of alpha + beta receptor that
lead to decrease in blood pressure.
For example: Carvedilol, labetalol etc.

17. 7. Alpha adrenergic blocker: The alpha blocker binds to the a – receptor on the blood vessels
and inhibit alpha -1 receptor on the blood vessels that may lead to decrease the blood
8. Central sympatholytics: Centrally acting sympatholytics block sympathetic activity by
binding to and activating alpha-2 adrenoceptors then they inhibit NE release. This decrease
sympathetic outflow to the heart there by decreasing heart rate and contractility. Reduced
sympathetic output to the blood vessels then the decrease arterial pressure, decrease
vasodilation, decrease sympathetic vascular tone.
For example: Methyldopa, clonidine etc.
9.Vasodilators: The vasodilators drugs relax the smooth muscles in blood vessels, which cause
the vessels to dilate. The dilation of arterial (resistance) vessels leads to a reduction in systemic
vesicular resistance which leads to fall in arterial blood pressure.
For example: Hydralazine, minoxidil sodium