Prescription Drugs and High Blood Pressure

Hypertension is effecting around billions of people worldwide. It is now one of the major causes of death in western countries.  At the initial stage of hypertension, doctors may recommended you to bring certain lifestyle changes like daily exercise, diet control, or meditation, yoga or herbal preparation. These methods can lower blood pressure significantly but it requires more time for bringing blood pressure to normal level.

In emergency conditions or when systolic BP is above 225mmHg, we need to go for antihypertensive drugs. These drugs produce quick action but yes they also invite certain side effects with them. There are various classes of prescription drugs available for the treatment of hypertension. However combination of low dose of drug along with lifestyle modification is not a bad option.

We would discuss in this article regarding certain prescription drugs and high blood pressure reduction.

Classes of Anti-hypertensive drugs

1. Diuretics

Diuretic drugs are prescribed as first line drug in the treatment of hypertension, which means that diuretic does play important role for treatment of high blood pressure (HBP). Diuretics promote excretion of excess of sodium and fluid through urine.   Thus, people taking diuretic may observe increase in volume and frequency of urination but this situation are not observed with everybody.  Diuretics also promote dilation of blood vessels which in turn contributes in lowering blood pressure. Diuretics are more effective in old aged people, African Americans and diabetic patient. This is the oldest yet most commonly used anti-hypertensive drug. Diuretics are divided into 4 classes –

  • Class IA- thiazide and thiazide like diuretic.
  • Class IB- potassium sparring diuretic
  • Class IC- diuretics with potassium supplements.
  • Class ID- loop diuretic

Thiazide and thiazide like diuretic:

Out of the above mentioned classes, the only preparation used presently for treating HBP is thiazide and thiazide like drugs. Earlier it was prescribed for treating heart failure but its blood pressure reducing effect has switched its main application as anti-hypertensive drug.

Some of the drug belonging to this category includes:

  • Chorothiazide
  • Chlorothalidone
  • Hydrochlorothiazide
  • Polythiazide
  • Indapamide
  • Metolazone

Possible Side effects:prescription drugs for blood pressure

Thiazide reduces the level of potassium from body but there is no effect on potassium level if you are having a healthy lifestyle. When consumed in high amounts, thiazides may lead to condition of impotence, gout and glucose intolerance, especially in diabetic patient. However such effects can be avoided by consuming low doses of thiazide diuretic. The recommended daily dose for bendroflauzide is 2.5 mg, for chlorthalidone is 25 mg, hydrochlorothiazide is 25mg and for cyclopenthiazide is 0.25mg.

Thiazide diuretic also reduces the excretion of calcium but this action is considered advantageous as it reduces the chances if development of kidney stones and osteoporosis in women after menopause.

Class IB and IC

Thiazide diuretic reduces the level of potassium in body. To compensate the decreased potassium level, two new classes of drugs are given along with thiazide diuretic; potassium sparing diuretic which reduces excretion of potassium and diuretic with potassium supplements which replaces the lost potassium. But these drugs are not prescribed as it increases the level of potassium in body, a condition known as hyperkalaemia which is more dangerous than low potassium level. 

Loop diuretic
Loop diuretic are mainly used in the treatment of heart or kidney failure that can arise from HBP so, it can be prescribed in such conditions. It discharges sodium and fluid through kidney and increases the frequency of urination.

2. Beta blockers

Another class of drug that is usually considered as first line drug is beta blockers or more specifically beta adrenergic blocker. These drugs are very effective for treatment of hypertension but effect is lesser as compared to diuretics. This drug is often used in combination with other drugs. It lowers high BP by blocking transmission of nerve impulses from brain to spiral muscles surrounding arteries and thereby reducing heart rate. It also decreases synthesis of adrenaline which acts as heart stimulating substance.

Benefits

Beta blocker has centrally mediating activity, therefore helps to calming down people in condition of nervousness or anxiety. The best part with beta blocker is that they are not addictive.  It also corrects the disturbances in heartbeats known as arrhythmias. Beta blocker is even effective in preventing the attack of angina. It is also prescribed to patients who already had one heart attack as it reduces the chances of prevalence of second heart attack. The combination of ACE inhibitors and beta blockers are used to reduce the risk of death due to heart failure.

Side effects

By regular intake of beta blockers, a person may get tired easily or feel fatigue. Cold hands and feet is another problem associated with beta blockers. Beta blockers can cause erection problem or impotence. If your heart beat is slow i.e. less than 6o beats per minute, you should avoid this drug as it slows down heartbeat. Beta blockers provokes bronchoconstriction, therefor should be avoided in people suffering from asthma.

Beta blockers drugs:

Some drugs belonging to class of beta blockers is mentioned below-

  • Acebutolol
  • Atenolol
  • Bisoprolol
  • Carteolol
  • Metoprolol
  • Propranolol
  • Nadolol
  • Sotalol
  • Timolol

3. Angiotensin converting enzyme (ACE) inhibitor

While talking about prescription drugs and high blood pressure, we cannot miss one important class i.e.  ACE inhibitors. These are recently approved drugs but undoubtedly an important component in prescription plan of HBP patient.  ACE inhibitor works by blocking an angiotensin converting enzyme, which contributes to the rise in blood pressure by promoting synthesis of angiotensin II from angiotensin I. therefore ACE inhibitor leads to dilation of blood vessels and even lowers the resistance to blood flow, thereby reducing HBP. ,

Apart from dealing with high blood pressure, these drugs are even prescribed in condition of heart failure, kidney failure or diabetes and in people at high cardiovascular risk. In patients who are at high risk of cardiovascular disease or who had heart failure, ACE inhibitor reduces chances of heart attack or stroke by improving and regulating the heart function. It is believed that effect of ACE inhibitor and beta blockers is less in Africans than any other ethnics.

Side effects

The most common side effect of ACE inhibitor includes skin rash, dry cough and bitter or no taste especially in case of captopril.
ACE inhibitor should be avoided during pregnancy as it may lead to foetal abnormality like impaired growth of baby’s skull or can reduce volume of amniotic fluid (a fluid surrounding baby in the womb).

Intake of ACE inhibitor should be avoided with thiazide diuretic because it can cause reduction in blood pressure to large extent and may lead to kidney failure. People who want to take ACE inhibitor should first of all stop diuretic intake and wait for 7 days before ACE inhibitor consumption.  It is generally advice to drink more water with 1 teaspoonful of salt and 1 tablespoon of sugar especially for people with kidney failure. This is to compensate the loss of water in case of diarrhoea or vomiting in patients prescribed with ACE inhibitor.

Drugs belonging to class of ACE inhibitor include-

  • benazepril
  • captopril
  • enalapril
  • fosinopril
  • lisinopril
  • ramirpil
  • Quinapril
  • Trandolapril

4. Angiotensin II receptor blocker (ARB)

ARBs perform similar function as ACE inhibitor, but instead of blocking the production of angiotensin II, it inhibits its action on heart and arteries by blocking receptors. It produce less side effect as compared to ACE inhibitors, the main side effect include headache, dizziness and fatigue. It is used in treatment of dry cough developed due to ACE inhibitors.

Drugs belonging to this class include-

  • Candesartan
  • Irbesartan
  • Losartan
  • Telmisartan
  • Valsartan

5. Renin inhibitors

Renin inhibitors are the latest drugs which are included in the regime of curing high blood pressure. Renin-angiotensin system of body regulates the blood pressure in the body and may the main cause for hypertension. Renin is an enzyme that works by converting angiotensinogen to angiotensin I. This angiotensin I is later converted to vasoconstricting agent angiotensin II by ACE. Unlike ACE inhibitors, these drugs inhibit the production of renin, therefore there would be no production of angiotensin II and no rise in BP would be observed.

Rasilex, a renin inhibitor drug, is very potent and effective drug available for the treatment of hypertension. Unlike ACE inhibitor, this drug does not produce any side effects like dry cough, swollen ankles, headache or dizziness. This drug is an important category of drug coming under prescription drug and high blood pressure as it produce significant effect on blood pressure even when prescribed alone for the treatment of hypertension.

6. Calcium channel blocker (CCB)

Another category of drug falling under the topic of prescription drugs and high blood pressure is calcium channel blocker. The name itself suggests that it blocks the entry of calcium. However these drugs affects only calcium channel of heart and arteries and no effect on the calcium channel of bone or in case of osteoporosis. The blockage of calcium leads to dilation of blood vessels and permits easy flow of blood and finally HBP lowers down. It is also effective in treatment of angina or arrhythmia.

Side effects-
Due to increase in blood flow, patients may experience head ache and dizziness after taking calcium channel blocker.  This effect is associated more with short acting CCB, but effects wears off after some dyes. Ankle swelling may be observed by taking long acting CCB especially if patient is resistant to diuretics. Short acting CCB have also shown some cases of heart attack and strokes in patient with heart failure, so, avoid it under such condition.

Drugs’ belonging to class of CCB includes-

  • Amlodipine
  • Bepridil
  • Diltiazem
  • Nifedipine
  • Nimodipine
  • Verapamil
  • Nisodipene

7. Alpha Adrenoceptor blocker

Alpha adrenoceptor blocks the production and binding of substances that produces constriction of blood vessels. Therefore the blood vessels relax and promote the easy blood flow and consequently HBP drops down. It should be avoided in patient with heart failure as many cases of heart attack and death associated with the use of adrenoceptor blocker have been reported.

Side effect

When taken for first time, you may faint by the effect of alpha adrenergic blockers. Therefore, it must be the last thing given at the night before going to sleep when taking for the first time Alpha adrenergic drug should also be avoided elderly people as they  suffer from more fainting attacks frequently even after long usage of this drug. Patient may suffer from headache, palpitation or dizziness when they change posture like from sitting to standing.

Alpha adrenoceptor drugs includes-

  • Doxazosin
  • Prazosin
  • Terazosin

Alpha and beta combination product like carvedilol and labetalol plays very effective role in the treatment of HBP and cardiovascular problems. Side effects of this product include headache and dizziness especially after change of position. This type of condition is also known as postural or orthostatic hypertension.

8. Centrally acting antihypertensive drug

The name itself suggests that this drug controls blood pressure by action on brain stem, which is found between brain and spinal cord. Brain stem controls certain important process of body including regulation of heart output, urine output and diameter of arteries which are critical.