It’s hardly news that high blood pressure increases your risk of a heart attack, a stroke, chronic kidney disease, and other serious health problems. Fortunately, there’s plenty most of us can do to lower elevated blood pressure, including healthy lifestyle changes and a variety of different classes of hypertension medications. But even those strategies aren’t enough for some people, and their blood pressure remains high, a condition called resistant hypertension.
Resistant hypertension at a glance
Healthy lifestyle and medications are usually enough to lower high blood pressure. But some people have resistant hypertension, which doesn’t respond to standard therapy. You may have resistanthypertension if:
- You take at least three different blood pressure medications, and
- You take them as directed (no skipping pills or forgetting to refill a prescription), and
- Your blood pressure readings are still higher than they should be.
It’s been a decade since the American Heart Association (AHA) released its first-ever scientific statement for diagnosing and treating resistant hypertension. Since then, a wide range of research findings has shed fresh light on resistant hypertension and the best ways to treat it. In September 2018, the AHA published a revised scientific statement for resistant hypertension, based on the latest research, in the journal Hypertension. The statement underscores the importance of getting an accurate diagnosis and employing proven treatment strategies.
The AHA considers hypertension to be a blood pressure reading of greater than 130/80 mm Hg (millimeters of mercury). It’s considered resistant when one or both of the following factors are present:
- Blood pressure remains elevated despite the concurrent use of three or more classes of antihypertensive drugs, which typically include a calcium channel blocker, a diuretic, and an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB), administered at the maximum dose a patient can tolerate
- Blood pressure requires four or more antihypertensive drugs to achieve a target goal
Researchers don’t fully understand what makes some people’s blood pressure resistant to treatment. African-Americans, older adults, and men are at increased risk of resistant hypertension. It also puts patients at especially high risk for health problems associated with hypertension, such as a stroke, a heart attack, heart failure, kidney disease, and earlier death than people with better-controlled hypertension.
Underlying causes to rule out
Before your doctor can confirm that you have resistant hypertension, he or she must rule out other underlying causes, most of which are reversible, such as:
- Poor adherence to the prescribed drug regimen. Fifty to 80 percent of people who need blood pressure–lowering medications don’t take them as directed, resulting in poorly controlled blood pressure, according to the AHA. One in four patients prescribed high blood pressure pills never fills the initial prescription. If you’ve been taking your medications haphazardly, sticking with your treatment plan could quickly bring your blood pressure under control.
- White-coat hypertension. When some people visit their doctors, they may reflexively feel anxious, which can cause an abnormal rise in blood pressure, resulting in what’s known as white-coat hypertension. To determine whether an elevated level is a white-coat effect, your doctor may ask you to take your own blood pressure readings at home or wear a portable blood pressure monitor for 24 to 48 hours. If your home blood pressure levels are reliable and lower than your in-office measurements, you likely don’t have resistant hypertension.
- Poor lifestyle and dietary habits. Obesity, physical inactivity, a high-sodium diet, and heavy alcohol use contribute to high blood pressure. Even if you’re taking antihypertensive medications, you still need to exercise regularly;maintain a healthy weight; limit alcohol; and follow a well-balanced, low-sodiumdiet, such as the DASH (Dietary Approaches to Stop Hypertension) diet.
- Errors in blood pressure measurements. If your doctor or nurse doesn’t followthe recommended technique for measuring blood pressure, the result might be inaccurate. For example, you should sit quietly with your legs uncrossed and your back, arms, and feet supported, ideally for at least five minutes before the test is performed. The wrong cuff size, background noise, talking (by either you or the clinician), and even a full bladder can affect blood pressure levels.
- Inadequate therapy. Your doctor may have communicated your drug regimen to you in a way that has led you to misunderstand his or her instructions, resulting in insufficient treatment that’s sometimes mistaken for patient nonadherence. He or she may also be reluctant to intensify therapy when your blood pressure remains too high. This failure to prescribe additional therapy is called therapeutic inertia. If you have high blood pressure that doesn’t respond to therapy, ask your doctor toreview your drug regimen to be sure you’re taking your medications correctly. Also ask whether you’re taking an optimum dose and whether you should be taking any additional hypertensive medications.
- Pain medications and other drugs. Several pain relievers can raise blood pressure and contribute to resistant hypertension in varying degrees in some, but not all, people. They include nonsteroidal anti-inflammatory drugs (NSAIDs) suchas ibuprofen (Advil, Motrin, others), naproxen (Aleve, Naprosyn, others), andcelecoxib (Celebrex). NSAIDs can also interfere with the treatment effects of some antihypertensive drugs. Other drugs that can boost blood pressure include decongestants, diet pills, amphetamine-like stimulants, some antidepressants, glucocorticoids, and the immunosuppressive drug cyclosporine. If you take any of these drugs regularly, talk with your doctor about other options.
Tips to Stay on Track with Blood Pressure Meds
Whether because of cost, complexity of the regimen, or simple forgetfulness, many people don't always take their prescribed medications. These strategies—some of which you do on your own, some with your doctor's help—can help keep you on track.
It’s important for your doctor to review your complete health history since unrelated medical conditions can contribute to resistant hypertension or increase the dangers of elevated blood pressure. Most secondary causes can be managed, and blood pressure lowered.
Contributing factors include:
- Renal artery stenosis—a narrowing of the arteries that carry blood to the kidneys
- Obstructive sleep apnea—a disorder characterized by pauses in breathing thatresult in temporary oxygen deprivation
- Chronic kidney disease—damage to the kidneys that causes their gradual lossof function
- Primary aldosteronism—a disorder involving a hormone produced by the adrenal glands called aldosterone, which causes potassium loss and sodium retention
If treating or managing any underlying or secondary causes doesn’t lower your blood pressure, a variety of treatment strategies can help reduce resistanthypertension. Making healthy lifestyle changes is the first line of treatment.
If lifestyle changes and strict adherence to drug therapy don’t work, yourdoctor might intensify your treatment by doing one or more of the following:
- Increase your dosages or change your dosing times.
- Switch your current diuretic with a long-acting thiazide diuretic—eitherchlorthalidone (Thalitone, Hygroton) or indapamide (Lozol)—if you’re notalready taking one.
- Add a fourth drug to your regimen, typically another type of diuretic calledan aldosterone antagonist, such as spironolactone (Aldactone, CaroSpir) oreplerenone (Inspra).
Even after following the above strategies, not everyone responds sufficiently.If you haven’t met your blood pressure goals after six months of treatment, yourdoctor might refer you to a specialist with expertise in managing resistant hypertension.
This article first appeared in the January 2019 issue of UC Berkeley Health After 50.
Also see Measuring Your Blood Pressure at Home.
Published January 22, 2019