DRUG INDUCED HYPOTENSION

DRUG INDUCED HYPOTENSION

Low blood pressure, or hypotension, occurs when blood pressure during and after each heartbeat is much lower than usual. This means the heart, brain, and other parts of the body do not get enough blood.  Blood pressure does not stay the same all the time.  It lowers as we sleep and rises when we wake up.  Blood pressure also rises when we are excited, nervous, or active.  Our body is very sensitive to changes in blood pressure.  For example, if we stand up quickly, our blood pressure may drop for a short time. 

The body adjusts our blood pressure to make sure enough blood and oxygen are flowing to our brain, kidneys, and other vital organs.  Most forms of hypotension happen because our body can't bring blood pressure back to normal or cannot do it fast enough.  Some people have low blood pressure all the time. They have no signs or symptoms, and their low blood pressure is normal for them.  In other people, certain conditions or factors cause abnormally low blood pressure. As a result, less blood and oxygen flow to the body's organs.  For the most part, hypotension is a medical concern only if it causes signs or symptoms or is linked to a serious condition, such as heart disease.

Blood pressure that is borderline low for one person may be normal for another. Most normal blood pressures fall in the range of 90/60 millimeters of mercury (mm Hg) to 130/80 mm Hg. But a significant drop, even as little as 20 mm Hg, can cause problems for some people.   There are three main types of hypotension, which are orthostatic hypotension (including postprandial orthostatic hypotension), neurally mediated hypotension (NMH) and also severe hypotension.

Orthostatic hypotension (OH) is brought on by a sudden change in body position, most often when shifting from lying down to standing. This type of hypotension usually lasts only a few seconds or minutes. If this type of hypotension occurs after eating, it is called postprandial orthostatic hypotension. This form most commonly affects older adults, those with high blood pressure, and persons with Parkinson's disease.  NMH most often affects young adults and children. It occurs when a person has been standing for a long time. Children usually outgrow this type of hypotension.  Besides that, severe hypotension is brought on by a sudden loss of blood (shock), infection, or severe allergic reaction.

 A diagnosis could be done to test whether we are one of the hypotension’s patients or not.  A simple test for Orthostatic Hypotension measures the person's blood pressure while seated or reclining at rest, and again upon standing up.  A sudden, significant fall in blood pressure upon standing indicates orthostatic hypotension. Blood pressure may drop immediately upon standing, or any time during the first couple of minutes after standing. In addition, the heart rate should also be measured for both positions. A significant increase from supine to standing may indicate a compensatory effort by the heart to maintain cardiac output.  A tilt table test (occasionally called upright tilt testing, is a medical procedure often used to diagnose dysautonomia or syncope) may also be performed.

 For some people, the exact cause of hypotension may not be known. However, there are several causes of hypotension.  First of all is anemia, which occurs when you have fewer oxygen-carrying red blood cells than normal.  The second one is autonomic nervous system(ANS) and baroreflex problems (BP).  Your autonomic nervous system (ANS) helps control the function of your organs and your BP. When your ANS does not function properly, your body may not hold on to needed salts. Releasing too much salt from your body may cause increased urination and fluid loss, leading to hypotension. 

Your baroreflex function helps keep normal blood flow to your heart when you change your body position. When you have sudden changes in posture, such as standing quickly, your blood may pool (stay) in your legs. A normal baroreflex response prevents blood pooling in your lower body and helps return blood to your heart. Baroreflex problems mean the blood does not return to your heart as it should. Your BP may drop too low.

The third is blood loss.  Losing a large amount of blood from your body can cause hypotension. Blood loss leading to hypotension may occur after an injury.  The fourth is dehydration.  Dehydration occurs when you lose too much fluid from your body. You can become dehydrated when you do not drink enough liquids. Vomiting (throwing up), diarrhea (loose, watery bowel movements), and severe burns may also lead to dehydration.

The next is medical problems. For instance, heart problems that cause your heart to beat weaker than normal can lead to hypotension. When your heart is weak, it may not pump blood strongly enough through your blood vessels. Problems with your adrenal glands may lead to hypotension. Your adrenal glands make chemicals that help maintain the right balance of fluids in your body.  Furthermore, medicines also is one of the causes of hypotension.  Medicines used to treat high blood pressure, heart conditions, and cancer may cause hypotension. Medicines to treat pain, depression (deep sadness), and other mood disorders may also lead to hypotension.  

 The medicines that causes low blood pressure are commonly caused by drugs such as alcohol, anti-anxiety medications, certain antidepressants, diuretics, heart medicines, (including those used to treat high blood pressure and coronary heart disease), medications used for surgery and also painkillers.

 For instance, diuretics are taken for an example as they are a common medication used to lower the blood pressure.  These agents lower blood pressure primarily by reducing body fluids and thereby reducing peripheral resistance to blood flow.  However, they deplete the body’s supply of potassium, so it is recommended that potassium supplements be added or that potassium-sparing diuretics be used.  Beta-blockers inhibit the effects of epinephrine(adrenaline), thus easing the heart’s pumping action and widening blood vessels.  Vasolidation acts by relaxing small arteries to dilate and thereby decreasing the total peripheral resistance.  Calcium channel blockers promote peripheral vasolidation and reduce vascular resistance.

 There are also several causes that increase the risk for getting hypotension.  Firstly is age.  As your age increase, your risk for hypotension also increases. OH and postprandial hypotension most often occur in the elderly.  Next is the alcohol and drug abuse.  Drinking too much alcohol, too often, may increase your risk for hypotension.  Alcohol is found in beer, wine, whiskey, and other adult drinks.  Using street drugs, such as marijuana, may also increase your risk for hypotension.

The third factor is being bedridden, as having to stay in bed for a long period of time increases your risk for hypotension.  Weighing less than you should for your height also increases your risk for hypotension.  Besides, hemodialysis also increases the risk for getting hypotension.  Hemodialysis treatments remove extra fluid from your body when you have kidney failure. If too much fluid is removed from your body, your blood pressure may drop lower than it should.  Medical problems, diseases, such as diabetes, Parkinson's disease, and Alzheimer's disease, increase your risk for ANS problems and hypotension.

 Signs and symptoms of hypotension may include dizziness, fainting, cold and sweaty skin, fatigue (tiredness), blurred vision, or nausea (feeling sick to our stomach).  In extreme cases, hypotension can lead to shock.  Shock is a life-threatening condition that occurs when the body is not getting enough blood flow. This can damage multiple organs. Shock requires immediate medical treatment and can get worse very rapidly.

 When blood pressure is not sufficient to deliver enough blood to the organs of the body, the organs do not work properly and can be temporarily or permanently damaged. For example, if insufficient blood flows to the brain, brain cells do not receive enough oxygen and nutrients, and a person can feel lightheaded, dizzy, or even faint.

Going from a sitting or lying position to a standing position often brings out symptoms of low blood pressure. This occurs because standing causes blood to "settle" in the veins of the lower body, and this can lower the blood pressure. If the blood pressure is already low, standing can make the low pressure worse, to the point of causing symptoms. 

The development of lightheadedness, dizziness, or fainting upon standing caused by low blood pressure is called orthostatic hypotension. Normal individuals are able to compensate rapidly for the low pressure created by standing with the responses discussed previously and do not develop orthostatic hypotension.

When there is insufficient blood pressure to deliver blood to the coronary arteries (the arteries that supply blood to the heart's muscle), a person may develop chest pain (a symptom of angina) or even a heart attack.  When insufficient blood is delivered to the kidneys, the kidneys fail to eliminate wastes from the body, for example, urea (BUN) and creatinine, and increases in their levels in the blood occur.  Shock is a life-threatening condition where persistently low blood pressure causes organs such as kidney(s), liver, heart, lung, and brain to fail rapidly.

 Hypotension in a healthy person that does not cause any problems usually doesn't require treatment.  However, if you have signs or symptoms of low blood pressure, you may need treatment. Treatment depends on the cause of your low blood pressure. Severe hypotension caused by shock is a medical emergency. You may be given blood through a needle (IV), medicines to increase blood pressure and improve heart strength, and other medicines, such as antibiotics.

On the other hand, if you have orthostatic hypotension caused by medicines, your doctor may change the dose or switch you to a different drug. Do not stop taking any medicine before talking to your doctor. Other treatments for orthostatic hypotension include increasing fluids to treat dehydration or wearing elastic hose to boost blood pressure in the lower part of the body.

Those with NMH should avoid triggers, such as standing for a long period of time. Other treatments involve drinking plenty of fluids and increasing the amount of salt in your diet. (Ask your doctor about specific recommendations.) In severe cases, medicines such as fludrocortisone may be prescribed.           

         However, if it is not clear what is causing low blood pressure or no effective treatment exists, the goal is to raise your blood pressure and reduce signs and symptoms. Depending on your age, health status and the type of low blood pressure you have, you can do this in several ways, which are by increase the amount of salt in our meal, by drinking more water, by wearing compression stockings and also by taking medications.

First and foremost is by taking a high amount of salt in our meal.  Experts usually recommend limiting the amount of salt in your diet because sodium can raise blood pressure, sometimes dramatically. For people with low blood pressure, that can be a good thing. But because excess sodium can lead to heart failure, especially in older adults, it's important to check with your doctor before increasing the salt in your diet.

Next is by drinking more water.  Although nearly everyone can benefit from drinking enough water, this is especially true if you have low blood pressure.  Fluids increase blood volume and help prevent dehydration, both of which are important in treating hypotension.

Besides, it is also recommended for the hypotension’s patients to wear compression stockings.  The same elastic stockings commonly used to relieve the pain and swelling of varicose veins may help reduce the pooling of blood in your legs.

Last but not least, medication also could help in treating this low blood pressure disease.  Several medications, either used alone or together, can be used to treat low blood pressure that occurs when you stand up (orthostatic hypotension). For example, the drug fludrocortisone is often used to treat this form of low blood pressure. This drug helps boost your blood volume, which raises blood pressure. Doctors often use the drug midodrine (Orvaten, Proamatine) to raise standing blood pressure levels in people with chronic orthostatic hypotension. It works by restricting the ability of your blood vessels to expand, which raises blood pressure.

 The statistics made by Department of Health of a hospital  in  England in the year 2002 until 2003, there are 0.089% of the total population in England have hospital consultant episodes  for hypotension, which is approximately 11,359 citizen.  45% of them were for men and 55% were for women.  Furthermore, the statistics also showed that the old folks have a higher  tendency for this disease with 67% of hospital consultant episodes for hypotension occurred in people over 75, and only 9% of hospital consultant episodes for hypotension occurred in 15-59 year olds.

On the other hand, in Malaysia, there are a minority of the citizen that were affected with this low blood pressure disease.  This is because, there are a vast majority of the population that had hypertension resulted from the lifestyle in Malaysia.

In conclusion, there are a variety of causes that contribute to this disease, and the most common one are from drugs and medication. For example alcohol, anti-anxiety medications, certain antidepressants, diuretics, heart medicines, (including those used to treat high blood pressure and coronary heart disease), medications used for surgery and also painkillers.  However, most of the drugs give benefits more that disadvantages as they are used to treat diseases such as high blood pressure.  That is why they are used as medicine in medical field.