Session Hypertension. Table 1 describes one of them.

 

Session
10

 

Hypertension

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Content

32.1 Introduction

32.2 Classification of hypertension

32.3 Hypertension management

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Introduction

Hypertension (High Blood
Pressure) is defined as sustain elevation of blood pressure more than 140/90
mmHg. Hypertension is the most common cardiovascular disease and it is the
major risk factor for coronary artery disease, heart failure, stroke, renal
failure and myocardial infarction. The risk is progressively increased with
increasing blood pressure. Cardiovascular disease prevalence is strongly age
depended and predominantly affects in people who are older than 50 years.

Untreated or ineffective treatment is
usually associated with progressive elevation of blood pressure subsequently
vascular damage resulting resistance hypertension. Effective antihypertensive
therapy has showed dramatic declines in mortality rate associated with
cardiovascular disease risk.

This particular session details the theory
behind the use of pharmacological and non-pharmacological treatment methods in management
of hypertension.

 

Activity
1          

 

1.    
What is hypertension?

2.    
What is mean by systolic and
Diastolic blood pressure?

 

 

 

 

Classification of Hypertension

There are several types of
classification of Hypertension. Table 1 describes one of them. Systolic blood
pressure of 120-130 mmHg or Diastolic Blood pressure of 80-89 mmHg is
classified as Pre-hypertension. If systolic blood pressure      140-159 mmHg or diastolic blood pressure
90-99 mmHg is classified as Hypertension stage 1 and if systolic blood pressure
more than 160 mmHg or Diastolic Blood pressure more than 100 mmHg it is
classified as Hypertension stage 2.

Classification

Blood Pressure
(mmHg)

Systolic

Diastolic

Normal

                <  120            And   < 80 Pre-hypertension                120-139            Or     80-89 Hypertension, Stage 1                140-159            Or     90-99 Hypertension, Stage 2                 ?  160            Or     ? 100 Table 1 Classification of hypertension   Essential hypertension Hypertension without other known secondary cause is referred as essential hypertension or Primary hypertension. 95 % of patient does not have identifiable cause of High Blood pressure. Therefore essential hypertension is the most common type of hypertension.   Resistance hypertension Resistance hypertension is defined as when the non-pharmacological treatment with a diuretic and two other antihypertensive drugs belonging to different classes at adequate doses fail to achieve targeted blood pressure and without other causes (poor compliance, concurrent use of medications causing hypertension and white coat hypertension) for uncontrolled hypertension. Hypertensive emergencies Severe blood pressure elevation more than 180/120 mmHg associated with acute target organ damage (hypertensive encephalopathy, intracranial haemorrhage, cerebral infarction, acute pulmonary oedema, acute coronary syndrome aortic dissection, acute kidney injury) is defined as hypertensive emergencies.   Activity 2             1.     What is the different between essential hypertension and Resistance Hypertension? 2.     What are the medications that cause Hypertension           Hypertension management The desire in the treatment of hypertensive patient is to achieve minimum risk of cardiovascular disease. Therefore treatment may include 1.      Treatment for the prevention of possible cardiovascular disorders. 2.      Appropriate management of other comorbidities. 3.      Achieving the target blood pressure. The treatment in achieving above goals can be classified in to                                Non-pharmacological and pharmacological methods Non pharmacological management Adherence of healthy life style by all hypertensive patients is recommended despite of drug therapy. Patients with prehypertension and some stage 1 hypertensives with no compelling indication can be adequately treated with life style changes instead of medication. Life style changes may decrease blood pressure and also enhance the efficacy of pharmacological therapy. Life style modifications include 1.      Weight management Weight reduction reduces blood pressure and associated cardiovascular risk. 2.      Cessation smoking This does not directly effect on reducing blood pressure but interfere with the efficacy of some antihypertensive therapy. In addition Smoking greatly increases the cardiovascular risk. Therefore cessation may extremely reduce the associated cardiovascular risk.     3.       Cessation of alcohol consumption. Alcohol consumption and hypertension having leaner relationship between each other.in addition alcohol decreases the efficacy of antihypertensive therapy.    4.      Physical activity Aerobic exercise in moderate level doing at least 30 minutes per day has been shown to lower day time systolic and diastolic blood pressure in hypertensive patients.    5.      Having cardio protective diet. Hypertension patient should be adapted to Dietary Approach to Stop Hypertension (DASH) eating plan. The DASH is rich in vegetables, fruits and low fat dairy products and less in meat, sweets, saturated fat and sodium (not more than 100 mEq/L)     Activity 3             1.      How do you counsel a patient with essential hypertension for proper life style management?         Pharmacological management Drugs in Hypertension Antihypertensive drugs can be classified according to their mechanism of action.   1.      Diuretics a.       Thiazide and related agents (Hydrochlorothiazide, Indapamide, Chlorthalidone)   b.      Loop Diuretics (Furosemide, Bumetanide, Torsemide, Ethacrynic acid)   c.       K+ Sparing Diuretics (Amiloride, Triamterene, Spironolactone)     2.      Angiotensin converting enzyme inhibitors (ACEI) (Captopril, Enalapril, lisinopril, Quinapril, Ramipril, Benzepril, Fosinopril, Moexipril, Perindopril, Trandolapril)   3.      Angiotensin ?? receptor blocker (Losartan, Cansesartan, Irbesartan, Valsartan, Telmisartan, Eprosartan)                 4.      Sympatholytic drugs   a.       ? Adrenergic antagonist (Metoprolol, Atenolol, Bisoprolol)   b.      ? Adrenergic antagonist (Prazosin, Terazosin, Doxazosin, Phenoxybenzamine, Phentolamine)   c.       Mixed adrenergic antagonists (Labetalol, Carvedilol)   d.      Centrally acting agents (Methyldopa, Chlonidine, Guannabenz, guanfacine)   e.       Adrenergic neuron blocking agents (guanadrel, reserpine)     5.      Vasodilators a.       Arterial (Hydralazine, Minoxidil, Diazoxide, Fenoldopam)   b.      Arterial and venous (Nitroprusside)                     Essential hypertension management First line drugs §  Angiotensin converting enzyme inhibitors (ACI) §  Thiazide diuretics §  Calcium Channel blockers ·         Di Hydro Pyridine Calcium Chanel Blockers (DHP) ·         Non Di Hydro Pyridine Calcium Chanel Blockers (NDHP) §  Beta blockers are no longer recommended as first line therapy except patients with ischaemic heart disease or heart failure. However patients who are already well controlled with bête blockers, the therapy may be continued unchanged.   Second line drugs §  Potassium-sparing Diuretics §  Alpha Blockers §  Centrally acting antiadrenergic drugs §  Direct-acting vasodilators            How Do Drugs work   Blood pressure is……………… this can be showed in an equation as follows.   Blood pressure = Cardiac Output (CO) × Peripheral Resistance (PR)         CO Cardiac Output = Stroke volume (SV) × Heart Rate (HR)           SV   HR   PR Reduction of peripheral Resistance and Cardiac Output may reduce the blood pressure. If a drug is able to reduce pr  thos cn be use to reduce BP                                     ACEIs and ARBs The renin angiotensin system is a hormonal regulatory system which regulates fluid balance in the body by act on kidney. When renal blood flow is reduced angiotensin I is converted in to angiotensin II by the enzyme call angiotensin converting enzyme (ACE). Angiotensin II binds with angiotensin receptors, resulting increased blood pressure. ACEI blocks the conversion of angiotensin I in to angiotensin II by inhibiting ACE. ARB blocks the binding of angiotensin II in to its receptor. Both drug types may reduce further process to increased blood pressure.                                                                      (      )                                                                                                                Figure 1 mechanism of ACEI and ARBs          Thiazides Thiazide diuretics act on the cortical diluting segment of the ascending limb of loop of henle and inhibit the NaCl co-transporter mechanism. This may enhance the sodium and water loss from the body. Subsequently Stroke volume is reduced due to reduction of intracellular fluid volume. Long term use of thiazide diuretics reduces responsiveness of arteriolar smooth muscles towards endogenous vasoconstrictors. This will reduce peripheral resistance.     Lumen                     Thiazide     Reduce Blood pressure                 Calcium Channel Blockers Ionic Calcium is crucial electrolyte for living tissue.  Calcium ion concentration in outside the cell is very much higher than that in the inside. Calcium channels are responsible for the regulating the influx calcium in to cell. When these channels are blocked intracellular calcium level ruduce.                                                                                                                                          Activity 3             1.      Describe how other antihypertensive drugs reduce hypertension?     When to use each drugs                                                                                                                                           Condition Beneficial      Diabetes mellitus ACEI, ARB      Left ventricular hypertrophy ACEI, ARB     Micro albuminuria/albuminuria ACEI, ARB    Chronic kidney disease stage 1-3 ACEI, ARB     Chronic kidney disease stage 4-5 CCB, ACEI/ ARB (with caution due to hyperkalaemia)      Ischemic heart disease BB, ACEI, ARB, CCB*      Heart failure ACEI, ARB, BB, Diuretics     Stroke Thiazides, CCB   Preferred combination of antihypertensive drugs –     Thiazides and ARB/ACEI –     Thiazides and CCB –     ACEI/ARB and CCB –     DHP CCB (nifedipine/ amlodipine) and beta blockers Combination of NDHP CCB and beta blockers should be avoided   Combination of ACEI and ARB is not recommended                 Drug Doses   Drug class Drugs Dose range (mg/day) Dosing frequency Thiazides Hydrochlorothiazide Indapamide 12.5 - 25 (50) 1.25 - 2.5 1 - 2 1 ACEI Captopril Enalapril 25 - 150 5 - 40 2 - 3 1 - 2 ARB Losartan Telmisartan 25 - 100 20 - 80    1 - 2    1 DHP CCB Nifedipine SR Amlodipine 20 - 90 5 - 10    1 - 2    1                                                      NDHP CCB Diltiazem Verapamil 180 - 360 120 - 480    2 - 3    2 - 3 Beta blockers Atenolol Bisoprolol Metoprolol Carvedilol 25 - 50 5 - 20 100 - 400 12.5 - 50   1   1   1 - 2   1 - 2 Aldosterone antagonists Spiranolactone 25 - 50   1 Alpha blockers Prazocin 1 - 20   2 - 3 Centrally acting drugs Methyldopa 250 - 3000   2 - 3     Drug management in resistance hypertension  Adding 4th drugs to the existing regime •      Spiranolactone – the preferred 4th drug •      Alpha blockers •      Beta blockers •      Centrally acting drugs e.g. methyl dopa •      Vasodilators e.g. hydralazine       Drug management in hypertensive emergencies Drug Mechanism of action Indicated clinical situations Cautions / Contraindications Sodium Nitroprusside Direct arterial and venous vasodilator All clinical situations of hypertensive emergencies Raised intracranial pressure Cerebrovascular and cardiovascular insufficiency Renal and hepatic impairment Glyceryl trinitrate Venous  and arterial vasodilator Acute coronary syndromes Acute left ventricular failure Concomitant use of PDE 5 inhibitors Raised intracranial pressure Labetalol Combined alpha and beta adrenergic blocker Aortic dissection Neurological emergencies Pre-eclampsia and eclampsia Severe bradycardia, Phaeochromocytoma Acute left ventricular failure Hydralazine Direct arterial vasodilator Pre-eclampsia and eclampsia Dissecting aortic aneurysm  

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