What is resistant hypertension?
Resistant hypertension is a condition where your blood pressure remains high or uncontrolled despite the medications you take to lower it. Hypertension (high blood pressure) is a major health issue. But it becomes even more frustrating when you are on multiple medications and don’t see any improvements. People with hard-to-treat, resistant hypertension have a higher risk of stroke, kidney disease and heart failure than people whose high blood pressure is controlled.
If you have resistant hypertension:
- Your blood pressure stays high (reading of 130/80 mmHg and above) — even if you take three blood pressure-lowering medications including one diuretic (water pill).
- You are taking four or more medications to control your high blood pressure.
Sometimes an underlying medical condition, or secondary cause, can keep your high blood pressure resistant to medications.
Who is at risk for developing resistant hypertension?
You’re more likely to have resistant hypertension if you:
Symptoms and Causes
What are the symptoms of resistant hypertension?
High blood pressure itself rarely causes symptoms, which is why it’s called the “silent killer.” Some people can go years without even realizing they have hypertension. But untreated high blood pressure is potentially dangerous to your health.
You and your healthcare provider should monitor your blood pressure numbers regularly, especially as you get older. You can also measure it at home with a good, inexpensive electronic monitor, available at most drug stores or online.
However, if your blood pressure suddenly gets very high you may experience a hypertensive crisis with headaches, pounding in the chest, dizziness and shortness of breath. A hypertensive crisis needs attention immediately.
What causes resistant hypertension?
Lifestyle and diet
The following can all contribute to the development of both hypertension and resistant hypertension:
- Physical inactivity.
- A diet high in salt.
- Heavy alcohol intake.
Drugs and medications
A variety of medications including prescription and over-the-counter drugs, can contribute to poor blood pressure control.
- Painkiller medications, especially NSAIDs (non-steroidal anti-inflammatory drugs) like ibuprofen and naproxen.
- Nasal decongestants.
- Oral contraceptives (birth control pills).
- Ginseng, licorice or other herbal products.
Sometimes treatable secondary causes may be the source of your resistant hypertension. These conditions may be raising your blood pressure.
Examples of such secondary causes include:
- Primary hyperaldosteronism, an excessive production of certain hormones from the adrenal glands.
- Renal artery stenosis, a narrowing of the arteries of the kidneys.
- Chronic kidney disease.
- Sleep apnea.
- Less common causes include pheochromocytoma, a tumor in the adrenal gland; aortic narrowing; and Cushing syndrome, an overproduction of some steroid hormones.
Diagnosis and Tests
How is resistant hypertension diagnosed?
To make a diagnosis of resistant hypertension, your healthcare provider may:
Get a detailed history and physical exam. In a detailed history your provider may ask when your high blood pressure began and how long it’s been going on; current drugs you take (including herbal medications) and if you take them as prescribed; and questions about possible secondary causes of your uncontrolled hypertension.
The physical exam will look for abnormal changes in the eye (a condition called hypertensive retinopathy), and abnormal sounds called bruits (vascular murmur) over some major arteries. These bruits may signal abnormal deposits of fatty tissue, also called plaques, in these blood vessels.
Order laboratory tests. These may include a urine test for protein or albumin; blood tests for glucose, electrolytes such as sodium and potassium and the blood creatinine level. A blood test may be done for adrenal hormones, to screen for possible disease in the adrenal glands. In addition, since hypothyroidism can contribute to high blood pressure, you may also be tested for thyroid disease.
Order imaging studies. X-rays, ultrasound and CT scans and other tests may be ordered depending on other conditions your provider may need to rule out. For example, imaging tests of the kidneys may be done to rule out abnormal blockage of the arteries to the kidneys (renal artery stenosis).
Management and Treatment
How is resistant hypertension treated?
Your doctor may order tests for kidney disease or the presence of excess hormones that may be leading to high blood pressure. Imaging studies to check the adrenal gland, or for narrowing of arteries, may be needed. You may be asked to undergo a sleep study to check for sleep apnea. In addition, since hypothyroidism can contribute to high blood pressure, you may also be tested for thyroid disease.
Lifestyle changes can help improve blood pressure control. These measures include:
- Limiting salt and alcohol.
- Limiting use of NSAIDs for pain relief (acetaminophen can be used instead).
- Doing at least 30 minutes a day of aerobic activity several days a week.
- Treating sleep apnea with continuous positive airway pressure.
In about 40% of resistant hypertension cases, medications aren’t working because they are not being taken correctly. In order for the drugs to work, they must be taken every day at the correct dose, and the correct number of times per day.
If you have trouble taking your medicine correctly, talk to your doctor. He or she may ask about side effects that may keep you from taking all of your doses. If you have side effects from one drug, your doctor may prescribe another one. You may be switched to medicines that you only need to take once a day. Do not stop taking any medications before speaking to your doctor.
If you have been taking your medication correctly and still have resistant hypertension, your doctor may choose to add another medication. The most common classes of blood pressure medicines are diuretics, calcium channel blockers, and ACE inhibitors/angiotensin receptor blockers (ARBs).
Studies have shown that use of the diuretic chlorthalidone is very effective in treating hypertension. Sometimes a fourth type of medication—an aldosterone antagonist such as spironolactone—may be added to control blood pressure.
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