Hypertension is another name for High blood pressure (HBP).➤Usually hypertension is defined as blood pressure above 140/90.
If your blood pressure is extremely high, there may be certain symptoms to look out for,including:
High blood pressure brain symptoms:
1. Headaches
2. Blurred vision
3. dizziness
4. Nausea and vomiting
High blood pressure and heart symptoms:
1. Chest pain
2. Shortness of breath
Treating high blood pressure can take a multi-pronged approach including diet changes, medication, and exercise.
· High blood pressure drug:
These medication work in a variety of way to lower blood pressure.
1. ACE (Angiotensin Converting Enzyme) Inhibitors
2. Angiotensin || Receptor Blockers
3. α(Alpha)-Adrenergic Blockers
4. β(Beta)-Adrenergic Blockers
5. α + β Adrenergic Blockers
6. Calcium Channel Blockers
7. Diuretics (Water Pills)
8. Direct Renin Inhibitor
9. Central Sympatholytics
10. Vasodilators
CLASSIFICATION
1. ACE (Angiotensin Converting Enzymes) Inhibitors: ( ~PRIL )
Captopril
Enalapril
Lisinopril
Ramipril
Perindopril
Fosinopril
2. Angiotensin-II Receptor Blockers: (~SARTAN )
Losartan
Valsartan
Telmisartan
Candesartan
Irbesartan
3. Alpha(α) Adrenergic Blockers:
Prazosin
Terazosin
Doxazosin
Pentolamine
Phenoxybenzamine
4. Beta(β) Adrenergic Blockers:(~OLOL )
Atenolol
Propranolol
Metoprolol
Timolol
5. α + β Adrenergic Blockers:
Labetalol
Carvedilol
6. Calcium channel Blocker: ( ~DIPIN )
Nifedipin
Nimodipin
Nicardipin
Amlodipin
Felodipin
Lacidipin
Verapamil
Diltiazem
7. Diuretics:
Thiazides: Hydrochlorthiazide
Chlorthiazide
Chlorthalidone
Indapamide
High ceiling: Furosemide, etc.
Potassium(K+) Sparing:
Spironolactone
Amiloride
Spironolactone
Amiloride
8. Direct Renin Inhibitor:
Aliskiren
9. Central Sympatholytics:
Clonidine
Methyldopa
10. Vasodilators:
Arteriolar: Hydralazine
Minoxidil
Diazoxide
Arteriolar + Venous: Sodium nitroprusside
· [NOTE: Adrenergic neuron blockers (Reserpine, Guanethidine, etc.) and Ganglionic blockers (Pentolinium, etc.) are only of historical Importance, though reserpine is still marketed.]
1. ACE (Angiotensin Converting Enzyme) Inhibitors:
The liver produces molecules called Angiotensinogen when there is a decrease in blood pressure in the arteries
↓
The kidney will detect this and then produce a molecule called Renin
↓
Renin enters into circulation and is responsible for converting Angiotensinogen into Angiotensin-I
↓
Angiotensin-I will then circulate around the body and get in contact with a membrane-bound enzyme called ACE or Angiotensin converting enzyme which mainly resides in the lung tissues
↓
ACE(angiotensin converting enzyme) converts Angiotensin-I to Angiotensin-II
↓
Angiotensin-II Important regulator of blood pressure
↓
Angiotensin-II binds on to angiotensin-II receptors on many different types of cells around the body and depending on what cell angiotensin binds to it’s effect on the body differs so essentially it will result in an increase in blood pressure
↓
Effect of Angiotensin-II includes:
-Increasing sympathetic activity
-Vasoconstriction
-Stimulating the release of aldosterone
These effects all of them will lead t an increase in blood pressure
↓
ACE inhibitor ( ~Pril) is inhibits ACE(Angiotensin converting enzyme) so it inhibit the conversion of Angiotensin-I to Angiotensin-II
↓
Because of less Angiotensin-II means that decrease blood pressure.
· Dose:
Enalapril: 2.5-10 mg/day
(used alone they control hypertension in ~50% patients, and addition of a diuretic/ β-blocker extends efficacy to ~90%.)
· Side effects:
Dry cough
headache
Nausea/Vomiting
Diarrhoea
Angioedema
Rash
· Contraindications:
Pregnancy
Chronic cough
Asthma
Kidney disease
Allergy
2. Angiotensin-II Receptor Blockers:
As the name suggests the mechanism of action,
it blocks the binding of Angiotensin-II to its receptor
↓
so it will decrease the activity of Angiotensin-II
↓
decrease in blood pressure
(see figure no:01)
·
Dose:
Dose:
Losartan: 50 mg/day
(Addition of 12.5 gm/day hydrochlorothiazide further enhances the fall in BP.)
·
Side effect:
Side effect:
Headache
Nausea
Diarrhoea
Backpain
· Contraindication:
Pregnancy
Allergy
3. Alpha(α) Adrenergic Blockers:
*Aim is to work on the vessel epithelial cells. Surrounding the lumen of blood vessel is the endothelial cells and the smooth muscle cells.
· Smooth muscle cells contract = narrow lumen = increase BP.
 |
| (figure:02) |
↓
These receptor react to nor-adrenaline/adrenaline(NA/A) produced by the nerve fibers
↓
Noradrenaline will bind to the alpha-I receptor(αIR)
↓
This will cause or stimulate contraction of smooth muscle cell
↓
Vessel to become more smaller = narrow the lumen
↓
This will lead to an increase blood pressure
↓
alpha-I receptor(αIR) Blockers, they block alpha-I receptors(αIR) and inhibits the adrenergic activity leading to the decrease in blood pressure.
(alpha-I receptor(αIR) Blockers also have role in decreasing total cholesterol in the boy)
· Dose:
Prazosin GITS 2.5 mg, 5 mg tabs ; Prazopress 1,2mg tabs.
· Side effect:
Hypotension
4. Beta(β) Adrenergic Blockers:
Beta-receptor is everywhere in the body. β-blockers block beta-receptors which is important for sympathetic activity.
(i) The heart have cells called Pacemaker cells(they directly control the heart rate).
Pacemaker cells have receptors on them the beta-I receptor(βIR).
Adrenergic neurons target these pacemaker cells and release NA/A which will bind on to beta-I receptor(βIR)
↓
It’ll stimulate the pacemaker cells to fire more rapidly
↓
Increase the heart rate = increase cardiac output (CO)
↓
Increase in blood pressure.
Beta-blockers block the sympathetic function on the heart by blocking the beta-I receptor(βIR) ↓
Decrease heart rate = decrease cardiac output
↓
Decrease blood pressure
 |
| (figure:03) |
NA/A released by adrenergic cells
↓
The sympathetic nervous system can stimulate the beta-I receptor(βIR) of cardiac muscle cells
↓
Cause the chronic muscle cells to contract
↓
Contraction the heart is able to increase cardiac output(CO)
↓
increase blood pressure
Beta-blockers block the sympathetic function on the heart by blocking the beta-I receptor(βIR),
↓
decrease Myocardial contraction = decrease cardiac output(CO)
decrease Myocardial contraction = decrease cardiac output(CO)
↓
Decrease blood pressure
·
Side effect:
Side effect:
Bradycardia
Fatigue
Hypotension
Bronchoconstriction
·
Contraindication:
Contraindication:
Obstructive lung disease
PVD(peripheral vascular disease)
5. α + β Adrenergic Blockers:
It is a combined α and β blocker
· Acts faster than pure β blocker
Drugs:
*Labetalol: it has been used i.v. for rapid BP reduction in hyperadrenergic states, cheese reaction, clonidine withdrawal, eclampsia, etc.
*Carvedilol: This nonselective β+ weak selective α1 blocker produces vasodilation and has additional antioxidant/free radial scavenging properties. Carvedilol is a frequently selected drug for long term treatment of congestive heart failure(CHF).
6. Calcium channel Blocker(CCBs):
· Calcium channels are important channels in our body that allow the movement of calcium in and out of cells or cellular organelles.
· There are two main calcium channels:
(i) T-type calcium channel blocker
(ii) L-type calcium channel blocker
(i) T-type calcium channel blocker
(ii) L-type calcium channel blocker
T-type calcium channel blocker:
In the heart pacemaker cells which control the heart rate, there are T-type calcium channel. Calcium activity in the pacemaker cells cause the heart to pump faster and increasing the BP.
By using the T-type calcium channel blockers it will block calcium activity. And thus decrease heart rate, decrease cardiac output and then decrease blood pressure.
L-type calcium channel blocker:
It is found on smooth muscle cells.
Blood vessel which contain smooth muscles, L-type calcium channels allow influx of calcium into the muscle filaments which will cause contraction and this will increase BP. by using L-type calcium channel blocker block calcium channel. thus smooth muscle will relax and decrease BP.
· Side effect of Dihydropyridine:
Headache
Dizziness
Palpitation
· Contraindication:
Congestive heart failure
7. DIURETICS:
Diuretics works on the kidney. The functional unit of kidney are called nephrons. There are millions of nephrons in the kidney where diuretics work.
Mechanism of action of diuretics is to increase urine output, decrease fluid overload and this will decrease BP.
There are 3 types of diuretics:
(i) Loop diuretics
(ii)Thiazide diuretics
(iii) K+ sparing diuretics
(i) Loop diuretics
(ii)Thiazide diuretics
(iii) K+ sparing diuretics
· (1)Loop diuretics:
In the loop of henle in the ascending part there is channel which transports one sodium molecules, two chloride molecules and one potassium from the nephron back into circulation back into the blood vessel.
When sodium is reabsorbed in the blood, water follows loop diuretics inhibit the transport are transported by inhibiting the movement of chloride ions which will disrupt the whole transport so don’t get sodium moving into the blood vessel therefore don’t get water following and result in decrease in BP.
· (2) Thiazide diuretics:
Thiazide diuretics work on the distal part of the nephron.
Transporter which reabsorb sodium and chloride together, this will then draw water back into the blood which will increase the blood pressure in the body. Thiazide diuretics block this transporter and block sodium reabsorption and result in decrease in BP.
Side effect of loop and thiazide diuretics:
Hyperglycemia, hypokalemia, hyperuricemia, hypotension
· (3)K+ sparing diuretics:
It is also work on the distil part of the nephron.
Transporter which is reabsorb sodium but secretes potassium.
Potassium sparing diuretics inhibit the transporter and decrease the reabsorption of sodium which means decrease the reabsorption of water which subsequently decrease BP.
Side effect of K+ sparing diuretics:
Hyperkalemia, gynaecomastia.
8. DIRECT RENIN INHIBITORS:
· Aliskiren the only available member of the latest class of RAS inhibitors which act by blocking catalytic activity of renin and inhibiting production of Ang-I and Ang-II.
· Aliskiren is an equally effective antihypertensive as ACE inhibitors.
9. CENTRAL SYMPATHOLYTICS:
*Clonidine is imidazoline derivative having complex actions. Clonidine is a partial agonist with high affinity and high intrinsic activity at α2 receptors, especially α2A subtype in brainstem. The major haemodynamic effect result from stimulation of α2A receptors present mainly postjunctionally in medulla (vasomotor centre). This decrease sympathetic out-flow → fall in BP and bradycardia.
On chronic administration of clonidine decrease cardiac output contributes more to the fall in BP.
·
Dose:Start with 100 µg OD or BD,
Max. 300 µg TDS, orally or i.m.
CATAPRES 150 µg tab, ARKAMIN 100 µg tab.
·
Side effect:
sedation
mental depression
disturbed sleep
dryness of mouth
constipation.
*Methyldopa acts on central α2 receptors to decrease efferent sympathetic activity.it may be acting on a different population of neurones in the vasomotor centre than clonidine.
In large doses, methyldopa inhibits the enzyme dopa decarboxylase in brain and periphery → reduce NA synthesis and form the false transmitter methyl-NA in periphery as well. These mechanisms were considered to be responsible for the antihypertensive effect.
·
Dose: 0.25-0.5 g BD-QID oral.
·
Side effect:
Sedation
Reduce mental capacity
Dryness of mouth
Weight gain
Hepatitis
Fever
Rash
10. VASODILATORS:
· * Hydralazine:
Vasodilation:
Opens K+ channels and relaxes the smooth muscles of arteries.
This leads to decrease in peripheral vascular resistances.
↓
Decrease in arterial blood pressure.
·
Dose: 40 mg/d to 200 mg/d
·
Contraindication:
Ischemic heart disease
·
Side effect:
CNS: headache, dizziness
CVS: palpitation, flushing, angina
GIT: Nausea
SKIN: sweating, skin rashes.
*Minoxidil:
Opens k+ channels in smooth muscles of arteries.
↓
Hyperpolarization of smooth muscles leading to dilation of blood vessels.
↓
Decrease in peripheral vascular resistance.
↓
Decrease in blood pressure
·
Dose: 5-40 mg/d in single or divided doses.
·
Side effects:
CNS: headache
CVS: tachycardia, palpitation, angina
SKIN: sweating, flushing
RENAL: edema.
*DIAZOXIDE:
It is an effective and relatively long-acting parenteral vasodilator.
Opening k+ channel in the smooth muscles of arteries thus relaxing them.
↓
This decreases peripheral vascular resistance.
↓
Decreased arterial blood pressure.
↓
Relax sympathetic system stimulation.
·
Dose: Started with low doses about 50 to 150mg.
Dose: Started with low doses about 50 to 150mg.
Dose of 150mg should be increased after every 5 min until BP is lowered.
·
Contraindication:
Diabetes mellitus
Congestive cardiac failure.
·
Side effect:
CVS: angina
ENDO: hyperglycemia
RENAL: edema.
*SODIUM NITROPRUSSIDE:
It is poisonous if given orally because of hydrolysis into cyanide.
It dilates both arteries and venous vessels.
Its action is due to nitrous oxide.
· Side effect:
BLOOD: methemoglobinemia
THIOCYNATE POISONING: weakness, psychosis, muscle spasms
ENDO: delayed hypothyroidism
CYANIDE TOXICITY: arrhythmias
Official Site: Makpats.com