Some high blood pressure medications initially cause drowsiness, dizziness, and lightheadedness. Some even cause fainting on the first dose. The body usually adjusts to the effects of these medications and the side effects disappear. Consuming alcohol during the early phase of antihypertensive treatment could be risky because alcohol can also cause dizziness, drowsiness, and lightheadedness.


It occurs more often in older people who are taking a lot of medication. However, it can cause symptoms in younger people. There may be underlying medical conditions such as joint hypermobility syndrome, diabetes, parkinson’s disease, addison’s disease or autonomic failure. Dehydration, hunger, low body weight and deconditioning (being out of shape/unfit) can reduce blood pressure.
tilt table test – usually recommended if your doctor suspects you might have orthostatic hypotension or NMH (During this diagnostic test, a person lies on a table and then the table is tilted to raise the upper part of their body. This simulates the change in position from sitting or lying down to standing up. People with orthostatic hypotension or NMH may feel dizzy, lightheaded, or even faint when their position changes.)

Heart block: Heart block occurs when the specialized tissues that transmit electrical current in the heart are damaged by heart attacks, degeneration from atherosclerosis, and medications. Heart block prevents some or all of the electrical signals from reaching parts of the heart, and this prevents the heart from contracting as well as it otherwise would.


Enlarged heart. High blood pressure increases the amount of work for your heart. Like any heavily exercised muscle in your body, your heart grows bigger (enlarges) to handle the extra workload. The bigger your heart is, the more it demands oxygen-rich blood but the less able it is to maintain proper blood flow. As a result, you feel weak and tired and are not able to exercise or perform physical activities. Without treatment, your heart failure will only get worse.
Many things can cause your blood pressure to be too low, ranging from normal pregnancy-induced changes to dangerous underlying conditions, like heart problems or hormone disturbances. In some instances, what causes low blood pressure could be a simple case of dehydration brought on by vomiting, intense exercise, or the overuse of diuretics. In fact, even mild dehydration can trigger symptoms such as dizziness, confusion, or other symptoms of low blood pressure.
There are even more medication types that can lower blood pressure. Some of these are alpha blockers, vasodilators, and central alpha agonists. Your doctor may prescribe these medications if other medications have been ineffective or if you have another condition along with hypertension. Side effects can include fast pulse, palpitations, dizziness, diarrhea, or headaches.
An exception to this is those with very high blood pressure readings especially when there is poor organ function.[79] Initial assessment of the hypertensive people should include a complete history and physical examination. With the availability of 24-hour ambulatory blood pressure monitors and home blood pressure machines, the importance of not wrongly diagnosing those who have white coat hypertension has led to a change in protocols. In the United Kingdom, current best practice is to follow up a single raised clinic reading with ambulatory measurement, or less ideally with home blood pressure monitoring over the course of 7 days.[79] The United States Preventive Services Task Force also recommends getting measurements outside of the healthcare environment.[80] Pseudohypertension in the elderly or noncompressibility artery syndrome may also require consideration. This condition is believed to be due to calcification of the arteries resulting in abnormally high blood pressure readings with a blood pressure cuff while intra arterial measurements of blood pressure are normal.[81] Orthostatic hypertension is when blood pressure increases upon standing.[82]
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2019, A.D.A.M., Inc. Duplication for commercial use must be authorized in writing by ADAM Health Solutions.
About This Image: Chart showing potential causes of low blood pressure The risk of low and high blood pressure commonly increases as a person ages due in part to changes during the aging process. The flow of blood to a person's heart muscle and brain declines as a person ages, many times as a result of plaque buildup in their blood vessels. Approximately 10-20% of people over the age of 65 experience postural hypotension. While the causes of low blood pressure may not always be clear, it might be associated with things such as:

Blood pressure monitors for use at home can be bought at drug stores, department stores, and other places. Again, these monitors may not always give you a correct reading. You should always compare your machine’s reading with a reading from your doctor’s machine to make sure they are the same. Remember that any measurement above normal should prompt a visit to the doctor, who can then talk with you about the best course of action.
There are a number of factors that likely work together to cause high blood pressure. A family history of high blood pressure can make you more likely to develop the condition, so genetics likely plays a role. High salt intake (too much salt in the diet) or salt sensitivity occurs in some people, which can lead to hypertension, particularly in the elderly, African Americans, people who are obese, or people with chronic kidney (renal) disease.
^ Jump up to: a b c d e f Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo Jr. JL, Jones DW, Materson BJ, Oparil S, Wright Jr. JT, Roccella EJ, et al. (December 2003). "Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure". Hypertension. Joint National Committee On Prevention. 42 (6): 1206–52. doi:10.1161/01.HYP.0000107251.49515.c2. PMID 14656957. Archived from the original on 20 May 2012. Retrieved 1 January 2012.
Hypertension in African-Americans tends to occur earlier in life and tends to be more severe. Plus, some medications that work to lower blood pressure in other ethnicities may have limited effect on African-Americans. Thiazide diuretics (such as HCTZ) or a calcium channel blocker are recommended first choices along with the possible add-on of a second drug from either the ACE inhibitor class or the angiotensin II receptor blocker group.
If your systolic and diastolic blood pressure are in two different categories, doctors consider the number that is in the higher category. For example, if your blood pressure is 135/91, your systolic blood pressure is in the prehypertensive range and your diastolic blood pressure is in the range of Stage 1 hypertension. Your measurement or 135/91 would place you in the category of Stage 1 hypertension.
A reduction from 8% to 6% of cardiovascular events is known as an absolute risk reduction of 2%. This may seem small, but the translation is not small when applied to real world people. This can be understood more easily as something called “number needed to treat” which is calculated by 1 divided by the absolute risk reduction. In this case, an absolute risk reduction of 2% translates to a “number needed to treat” of 50 (1 divided by 0.02 = 50). This means that 50 people need to have a BP down to < 120/80 in order for 1 cardiovascular event to be prevented. In the context of many other things we do in our life (medical treatment or not), this is really good!
You will work with your provider to come up with a treatment plan. It may include only the lifestyle changes. These changes, such as heart-healthy eating and exercise, can be very effective. But sometimes the changes do not control or lower your high blood pressure. Then you may need to take medicine. There are different types of blood pressure medicines. Some people need to take more than one type.
Blood spots in the eyes : Blood spots in the eyes (subconjunctival hemorrhage) are more common in people with diabetes or high blood pressure, but neither condition causes the blood spots. Floaters in the eyes are also not related to high blood pressure. However, an eye doctor (ophthalmologist) may be able to detect damage to the optic nerve caused by untreated high blood pressure.   
Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017; pii: S0735-1097(17)41519-1. PMID: 29146535 www.ncbi.nlm.nih.gov/pubmed/29146535.
Meschia JF, Bushnell C, Boden-Albala B, et al; American Heart Association Stroke Council; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; Council on Functional Genomics and Translational Biology; Council on Hypertension.. Guidelines for the primary prevention of stroke: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(12):3754-3832. PMID: 25355838 www.ncbi.nlm.nih.gov/pubmed/25355838.
Postural hypotension is considered to be a failure of a person's cardiovascular system or nervous system to react appropriately to sudden changes. Usually, when a person stands up, some of their blood pools in their lower extremities. If this remains uncorrected, it would cause the person's blood pressure to fall or decrease. A person's body usually compensates by sending messages to their heart to beat faster and to their blood vessels to constrict, offsetting the drop in blood pressure. If this does not happen, or does not happen quickly enough, postural hypotension is the result.
Peter, I’ve been using a blood pressure meter for nearly 30 years, so my response is based on my personal experience and information I’ve acquired over the years. First, I suggest that you take your meter to the doctor and have them check several readings of your meter against theirs. For example, If your meter consistently shows it’s 10 points lower than the doctor’s, just delete the 10 points from your meter reading (have them check both numbers so you can adjust both as necessary). Also, it’s common that many doctor’s offices take your blood pressure incorrectly (you should actually sit still for 5 minutes, with your feet on the floor and the cuff at the same level as your heart) . Some of us have”white coat” hypertension, so you may always be elevated at the doctor’s office. If you are a large man, you (and your doctor’s office) may need to use a larger cuff as the wrong size of cuff can affect your reading. Also, I spoke with customer service at one of the companies that makes many of the home & professional meters, and she told me that the automated machines are not very accurate if you have kidney disease or heart failure (I have both). Ask the doctor’s staff to always use the manual system and it will be more accurate than those noisy automatic ones.

Exercise stress test: More commonly used for patients with borderline hypertension. This usually involves pedaling a stationary bicycle or walking on a treadmill. The stress test assesses how the body's cardiovascular system responds to increased physical activity. If the patient has hypertension this data is important to know before the exercise test starts. The test monitors the electrical activity of the heart, as well as the patient's blood pressure during exercise. An exercise stress test sometimes reveals problems that are not apparent when the body is resting. Imaging scans of the heart's blood supply might be done at the same time.

If dehydration contributes to the problem, increased fluid intake would be needed based in part on your body mass index (BMI). For example, a person with a normal BMI would likely only need eight to ten 8-ounce glasses of water per day to maintain ideal hydration. People with a high BMI may need far more. Adding more salt to your diet may also aid in normalizing your blood pressure.
The findings mean that an additional 14 percent of U.S. adults, or about 30 million people, will now be diagnosed as having high blood pressure, compared with the number diagnosed before the new guidelines. This will bring the total percentage of U.S. adults with high blood pressure to 46 percent, up from 32 percent previously. [9 New Ways to Keep Your Heart Healthy]
High blood pressure is more common in older people. At age 45, more men have hypertension than women. By age 65, this is reversed and more women are affected. People with diabetes have a greater risk of hypertension than those without diabetes. Having a close family member with high blood pressure also increases your risk of developing it. About 60% of all people with diabetes also have hypertension.
The primary symptoms of malignant hypertension is a blood pressure of 180/120 or higher and signs of organ damage. Other symptoms of malignant hypertension include bleeding and swelling of blood vessels in the retina, anxiety, nosebleeds, severe headache, and shortness of breath. Malignant hypertension may cause brain swelling, but this symptom is very rare.

This study is assessing the association between DNA, health behaviors, social and environmental factors, and risk factors of heart disease, such as high blood pressure, in African Americans. To participate you must be an African American between 21 and 65 years old, living in Washington, D.C., or Montgomery or Prince Georges counties in Maryland. Please note that this study is being conducted in Bethesda, Maryland.
The American Heart Association, or AHA, explains that the early symptoms of high blood pressure that people tend to think about are largely mythical. You are unlikely to notice “classic” signs such as anxiety, insomnia, or flushing in your face. You could have blood spots in your eyes due to subconjunctival hemorrhage, but dizziness itself is not among the essential symptoms of high blood pressure.

Much of the disease burden of high blood pressure is experienced by people who are not labeled as hypertensive.[87] Consequently, population strategies are required to reduce the consequences of high blood pressure and reduce the need for antihypertensive medications. Lifestyle changes are recommended to lower blood pressure, before starting medications. The 2004 British Hypertension Society guidelines[87] proposed lifestyle changes consistent with those outlined by the US National High BP Education Program in 2002[95] for the primary prevention of hypertension:

The information you share, including that which might otherwise be Protected Health Information, to this site is by design open to the public and is not a private, secure service. You should think carefully before disclosing any personal information in any public forum. What you have written may be seen, disclosed to, or collected by third parties and may be used by others in ways we are unable to control or predict, including to contact you or otherwise be used for unauthorized or unlawful purposes. As with any public forum on any site, this information may also appear in third-party search engines like Google, MSN, Yahoo, etc. Your use of this site is governed by Harvard University and its affiliates Terms of Use located at www.health.harvard.edu/privacy-policy and may be amended from time to time.


2. Take the right nutrients. Talk with your chiropractor or other healthcare professional about the wide range of well-studied nutrients that, along with dietary and lifestyle modifications, can help normalize your blood pressure. One meta-analysis found magnesium supplements could lower blood pressure. Likewise, researchers find a small but significant decline in blood pressure for people with hypertension who use fish oil. (You can get all of fish oil’s benefits combined with anti-inflammatory flax oil and GLA in our Optimal Omega.) 
Allergic reaction (anaphylaxis): Anaphylactic shock is a sometimes-fatal allergic reaction that can occur in people who are highly sensitive to drugs such as penicillin, to certain foods such as peanuts or to bee or wasp stings. This type of shock is characterized by breathing problems, hives, itching, a swollen throat and a sudden, dramatic fall in blood pressure.
×