Having trouble controlling your blood pressure?
Effectively treating high blood pressure is essential for good health, since the condition can cause heart attacks, strokes, heart failure and other life-threatening illnesses. But, what do you do if your hypertension is resistant to medications?
Resistant hypertension affects about 20 percent of patients with high blood pressure, according to Johns Hopkins Medicine. The ideal blood pressure is less than 120 over 80, according to the American Heart Association, and nearly half of the adults in the U.S. have hypertension.
“By definition, resistant hypertension is hypertension that is not adequately treated by three medications in three different groups, including a diuretic,” said cardiologist Lawrence McAuliffe, MD of Cape Cod Healthcare Cardiovascular Center in Hyannis. “Even if it is adequately treated, if you require four medications then you would by definition have resistant hypertension.”
The first question cardiologists ask when a patient’s blood pressure is not being adequately controlled is if the patient is actually taking the prescribed medications as directed. It stands to reason that if you don’t take the medication regularly, you don’t get the full benefit.
After that, there are two different approaches doctors use. The first is to maximize non-pharmacological risk factors that cause high blood pressure. This includes controlling sodium, eating a heart-healthy diet like the DASH diet, quitting smoking, limiting alcohol and exercising regularly.
It’s also important to make sure the patient isn’t taking an over-the-counter medication like cold or sinus remedies, pain relievers like ibuprofen and naproxen, or antacids with high sodium. All of those agents can raise blood pressure, as can licorice products.
“You have to review all of those things and make sure there aren’t some simple lifestyle things you can address or eliminate,” Dr. McAuliffe said.
The second step then would be to ensure that you are not dealing with secondary hypertension, which by its name suggests that there is another condition present that is causing the elevation of blood pressure, he said.
“If you treat that condition, the high blood pressure improves or goes away.”
The number one secondary condition that cardiologists see is renal artery stenosis, which is a narrowing of the blood vessel to the kidneys. When this type of blockage occurs the pressure in front of the blockage is high, but after the blockage it’s low. As the blockage gets more severe, the blood flow to the kidney is significantly impaired. The kidney responds by thinking your blood pressure is low so it releases hormones to raise blood pressure. That response starts a continuous loop that can become a vicious cycle, Dr. McAuliffe said.
“If it’s a single blockage, on one of the sides, you can stent it,” he said. “Once the blood flow is restored to the kidney, then the kidney is happy and it stops releasing those hormones and they end up being on far less medication.”
Other secondary causes of resistant hypertension include:
- Adrenal gland abnormalities where a substance that causes high blood pressure and sodium retention is released
- Pituitary gland conditions that release hormones that cause blood pressure to rise
- Sleep apnea, which causes low oxygen when you are sleeping
- Hyperthyroidism or hypothyroidism
When to Try a Different Medication
“You go down that laundry list of causes of secondary hypertension,” Dr. McAuliffe said. “After you have done all of that work and you’ve excluded or ruled out all of those things and changed all the things you can, if you still have someone who is resistant and has resistant hypertension, then you start trying different medications.”
In general, the recommendation is to start with a drug from three categories, beginning with a diuretic. The second class of medications are angiotensin converting enzyme inhibitor (ACEs) or angiotensin receptor blocking (ARBs). The current American Heart Association and the American College of Cardiology guidelines don’t recommend the ACEs because they are not usually as effective as ARBs and they can have side effects like a dry cough or swelling of the tongue, lips and throat.
The third class of medications are calcium channel blockers. Any or all of these medications can be adjusted as needed, in order to reach the American Heart Association’s target guidelines.
“If those three medicines at either maximum dose or maximum tolerated dose haven’t worked then there are other classes of medications that you can add,” Dr. McAuliffe said. “They would be the beta blockers, the alpha one blockers and vasodilators.”
There are also some more experimental therapies such as carotid artery stimulation, or renal artery denervation, but those remain somewhat controversial and would only be used on a very small minority of patients who have extremely dangerous high blood pressures. They are performed at tertiary care academic centers.
Patients who fail the conventional drug therapy strategy as discussed above should be considered for referral to a hypertensive specialty clinic, often at a tertiary care academic medical center, said Dr. McAuliffe.