Hypertension is defined as a systolic blood pressure over 140 mmHg or a diastolic blood pressure over 90 mmHg. It can be caused by environmental factors like stress, high sodium intake, smoking, and obesity. Antihypertensive drugs work through various mechanisms like diuretics which increase sodium excretion, ACE inhibitors which inhibit angiotensin II synthesis, and calcium channel blockers which relax smooth muscles. Lifestyle modifications and medication are important to control blood pressure and prevent complications of hypertension like heart disease and stroke.

1. BY
Shaikh Saniya

2. Hypertension
• Hypertension is defined as either a sustained systolic blood
pressure of greater than 140mm Hg or a sustained diastolic
blood pressure of greater than 90mm Hg.
• Hypertension results from increased peripheral vascular
smooth muscle tone, which leads to increased arteriolar
resistance and reduced capacitance of nervous system.
• Causes of hypertension
1. Stressful life style.
2. High dietary intake of sodium.
3. Smoking.
4. obesity.

3. BLOOD PRESSURE
ARTERIAL BLOOD = Cardiac Output X Peripheral PRESSURE
Resistance

4. Normal Regulation of Blood Pressure

5. Classification of Hypertension

6. Introduction
Hypertension
Systolic Blood
Pressure (SBP(
Diastolic Blood
Pressure (DBP(
<140mmHg <90mmHg
****************************************************

7. Types of
Hypertension
Essential Secondary
A disorder of unknown origin affecting the
Blood Pressure regulating mechanisms
Secondary to other disease processes
Environmental
Factors
Stress Na+ Intake Obesity Smoking
****************************************************

8. Environmental factors
1.STRESS
• Stress is a feeling of emotional or physical
tension. It can come from any event or
thought that makes you feel frustrated,
angry, or nervous.
• Stress is your body's reaction to a challenge
or demand.

9. 2.Increase Na intake
• A high blood sodium level (hypernatremia) is almost
always caused by losing too much water (dehydration)
without drinking enough water.
• In rare cases, it may be due to increased salt
intake without enough water, Cushing syndrome, or a
condition caused by too little ADH called diabetes
insipidus.

10. Effects of Hypertension
• Symptomatic treatment is Mandatory:
– Damage to the vascular epithelium, paving the path for
atherosclerosis (IHD, CVA) or nephropathy due to high intra-
glomerular pressure
– Increased load on heart due to high BP can cause CHF (ventricular
Hypertrophy)
– Brain- Hypertensive Encephalopathy
– Eyes- Retinopathy occlusion
– Normal effects- restlessness, uneasiness, sweating

13. Antihypertensive Drugs
• Diuretics:
– Thiazides: Hydrochlorothiazide, chlorthalidone
– High ceiling: Furosemide
– K+ sparing: Spironolactone, triamterene and amiloride
MOA: Acts on Kidneys to increase excretion of Na and H2O – decrease in
blood volume – decreased BP
• Angiotensin-converting Enzyme (ACE) inhibitors:
– Captopril, lisinopril., enalapril, ramipril and fosinopril
MOA: Inhibit synthesis of Angiotensin II – decrease in peripheral resistance
and blood volume
• Angiotensin (AT1) blockers:
– Losartan, candesartan, valsartan and telmisartan
MOA: Blocks binding of Angiotensin II to its receptors

14. Antihypertensive Drugs
• Centrally acting:
– Clonidine, methyldopa
MOA: Act on central α2A receptors to decrease sympathetic outflow – fall in
BP
• ß-adrenergic blockers:
– Non selective: Propranolol (others: nadolol, timolol, pindolol, labetolol)
– Cardioselective: Metoprolol (others: atenolol, esmolol, betaxolol)
MOA: Bind to beta adrenergic receptors and blocks the activity
• ß and α – adrenergic blockers:
– Labetolol and carvedilol
• α – adrenergic blockers:
– Prazosin, terazosin, doxazosin, phenoxybenzamine and phentolamine
MOA: Blocking of alpha adrenergic receptors in smooth muscles -
vasodilatation

15. Antihypertensive Drugs –
• Calcium Channel Blockers (CCB):
– Verapamil, diltiazem, nifedipine, felodipine, amlodipine, nimodipine
etc.
MOA: Blocks influx of Ca++ in smooth muscle cells – relaxation
of SMCs – decrease BP
• K+ Channel activators:
– Diazoxide, minoxidil, pinacidil and nicorandil
MOA: Leaking of K+ due to opening – hyper polarization of SMCs
– relaxation of SMCs
• Vasodilators:
– Arteriolar – Hydralazine (also CCBs and K+ channel activators)
– Arterio-venular: Sodium Nitroprusside

16. Diuretics

23. Angiotensin Converting Enzyme (ACE)
Inhibitors
What is Renin - Angiotensin?
(Physiological Background)

26. Renin blockers

27. Angiotensin Converting Enzyme
Inhibitors (ACE Inhibitors)

28. Angiotensin Receptor Blockers (ARBs) -

30. α - Methyldopa
It is a competitive inhibitor of the enzyme DOPA
decarboxylase, which converts L-DOPA into dopamine.
This inhibition results in
reduced dopaminergic and adrenergic neurotransmission in the peripheral
nervous system. This effect may lower blood pressure and cause central
nervous system effects such as depression, anxiety, apathy, anhedonia,
and parkinsonism.
It is converted to α-methylnorepinephrine by dopamine beta-
hydroxylase (DBH).
α-Methylnorepinephrine is an agonist of presynaptic central nervous system
α2 adrenergic receptors.
Activation of these receptors in the brainstem appears to inhibit sympathetic
nervous system output and lower blood pressure. This is also the mechanism of
action of clonidine.

31. Clonidine

32. Beta-adrenergic blockers
• Beta blocker reduce blood
pressure primarily by
decreasing cardiac output.
• They may also decrease
sympathetic outflow from the
CNS and inhibits the release of
rennin from kidney , thus
decreasing the formation of
angiotensin II and the
secretion of aldesterone.

34. Beta-adrenergic blockers
• Advantages:
– No postural hypotension
– No salt and water retention
– Low incidence of side effects
– Low cost
– Once a day regime
– Preferred in young non-obese patients, prevention of sudden cardiac
death in post infarction patients and progression of CHF
• Drawbacks (side effects):
– Fatigue, lethargy (low CO?) – decreased work capacity
– Loss of libido – impotence
– Cognitive defects – forgetfulness
– Difficult to stop suddenly
– Therefore cardio-selective drugs are preferred now

35. Αlpha-adrenergic blockers

39. Calcium Channel Blockers -
Classification

42. Direct Acting Vasodialators

44. Thankyou