Hypertension (high blood pressure) can lead to serious health problems over time. Many people have trouble keeping it under control, even with treatment.

Here’s a closer look at what can cause uncontrolled hypertension and the symptoms that may occur.

What Causes Uncontrolled Hypertension?

There are many reasons why blood pressure can be hard to control. The following factors may contribute to uncontrolled or resistant hypertension.

Blood Pressure Medication Issues

Sometimes blood pressure stays high because of an issue with how medications are taken, their dosage, the medication combination, or their timing.

Possible issues include:

• Difficulty following a treatment plan — If you have a hard time taking your medication exactly as prescribed, it may not control your blood pressure as effectively.
• A medication dose that’s too low — Your doctor may determine that increasing your dose could improve your blood pressure control.
• A medication combination that isn’t working well — Your doctor may recommend adding another medication or changing the combination of medications you take.
• Medication timing — If you take more than one medication, your doctor may recommend taking them at different times, such as one in the morning and another in the evening.

Talk with your doctor if you have concerns about your treatment plan, especially if it’s difficult to take your medication as prescribed. Don’t change your medication dose or timing without talking with them first.

Medications and Supplements That Increase Blood Pressure

Some medications and supplements can raise blood pressure or make blood pressure medications less effective.

The following medications and supplements may contribute to high blood pressure:

• Antidepressants
• Hormonal birth control pills
• Decongestants (often found in cold medicines)
• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, as well as high-dose aspirin
• Caffeine pills and herbal supplements such as ginseng or licorice
• Certain biological therapies, including angiogenesis inhibitors and some monoclonal antibodies
• Some immunosuppressants (medications that reduce immune activity)
• Stimulants used to treat attention-deficit/hyperactivity disorder (ADHD)

Talk with a healthcare provider about all the medications and supplements you take. This can help them identify anything that may be making your blood pressure harder to control.

Age, Sex, Race or Ethnicity, and Family History

Several personal factors can affect your risk of high blood pressure.

High blood pressure can run in families, suggesting a genetic link. As people age, their blood vessels can become stiffer and less flexible, which may raise blood pressure.

Patterns also vary by sex and age. According to the National Heart, Lung, and Blood Institute, men are more likely to develop high blood pressure in middle age, whereas women are more likely to develop it as older adults.

The institute also reports that Black adults tend to develop high blood pressure earlier and more frequently than White, Hispanic, or Asian adults. Some blood pressure medications may also be less effective for Black adults than for people in other groups.

Underlying Medical Conditions

Your blood pressure may be difficult to control because of another health condition. About 25 percent of people with resistant hypertension have an identifiable underlying medical cause.

Healthcare professionals call this secondary hypertension (high blood pressure caused by another condition). When there’s no clear medical cause, it’s usually called primary or essential hypertension.

Health conditions that may make hypertension hard to control include:

• Sleep apnea — A condition in which breathing repeatedly stops and starts during sleep
• Renal artery stenosis — Narrowing of the arteries that supply the kidneys
• Kidney failure
• Coarctation of the aorta — Narrowing of part of the body’s main artery
• Cushing’s disease — A condition involving excess cortisol
• Pheochromocytoma — An adrenal gland tumor that produces hormones that can raise blood pressure
• Thyroid disorders
• Primary aldosteronism — A hormonal condition that affects the body’s salt balance
• Rare congenital neuroendocrine disorders — Conditions affecting hormone-producing nerve cells
• Higher weight or obesity
• Metabolic syndrome — A group of conditions that includes high blood sugar, high blood pressure, and excess abdominal fat

Smoking and Vaping

Smoking is a known risk factor for high blood pressure. Blood pressure also rises temporarily each time you smoke, and continuing to smoke after a diagnosis may make blood pressure harder to control.

Vaping (using e-cigarettes) may also affect heart and blood vessel health. In preliminary observational research, people who regularly vaped showed concerning changes in blood pressure, heart rate, blood vessel function, and exercise performance.

Some cardiovascular effects among people who vaped were similar to those observed among people who smoked cigarettes, even though the participants who vaped were younger and had used nicotine for less time. However, the research could not establish cause and effect, and the researchers could not directly compare the effects of vaping and smoking.

If you want help quitting smoking or vaping, talk with a healthcare provider about support options.

Alcohol Use

Drinking alcohol is associated with higher blood pressure, and heavier drinking may make blood pressure harder to control.

A large observational study found that cutting back on alcohol or stopping altogether was associated with lower blood pressure. Because the study was observational, it could not prove that the changes in alcohol intake caused the differences in blood pressure.

For some people, avoiding alcohol altogether may be part of managing blood pressure. Talk with your healthcare provider about what’s appropriate for you.

If you’re concerned about your alcohol use, consider talking with a healthcare provider or mental health professional. You can also visit FindTreatment.gov to look for support.

What Are the Symptoms of Uncontrolled Hypertension?

Most people with high blood pressure don’t experience symptoms. That’s why the condition is sometimes referred to as the silent killer.

A few people may experience nonspecific symptoms such as headaches, shortness of breath, or nosebleeds. These symptoms usually don’t occur until blood pressure has reached a severe or life-threatening level.

If extremely high blood pressure is causing organ damage — a hypertensive emergency — more serious symptoms may occur. These include:

• Dizziness
• Edema (swelling, often in the legs or feet)
• Confusion or trouble thinking clearly
• Urinating less than usual
• Heart palpitations
• Vision changes, such as blurred vision or vision loss
• Signs of a stroke, such as sudden weakness, trouble speaking, or facial drooping
• Seizures
• Severe headache
• Shortness of breath
• Chest pain or discomfort

Call 911 if you have these symptoms and a blood pressure reading of 180/120 millimeters of mercury (mm Hg) or higher. If you’re pregnant, seek emergency care if you have these symptoms and your blood pressure is 160/110 mm Hg or higher.

What Happens if You Have Uncontrolled Hypertension?

Hypertension can damage the walls of large arteries, such as the aorta and carotid arteries, as well as smaller vessels in organs such as the eyes. As this damage builds, blood flow becomes less efficient, and the heart has to work harder to pump oxygen- and nutrient-rich blood throughout the body.

This added strain can affect multiple parts of the body, including the heart, brain, eyes, and kidneys.

Over time, uncontrolled hypertension can increase the risk of complications such as:

• Heart attack
• Stroke
• Coronary artery disease (reduced blood flow through the arteries that supply the heart)
• Heart failure (when the heart can’t pump blood as well as it should)

It may also contribute to vision loss, chronic kidney disease (long-term kidney damage), and sexual dysfunction.

What Should You Do if You Have Uncontrolled Hypertension?

If your blood pressure remains above your target despite taking medication, talk with your doctor about different or additional treatment options.

Lifestyle changes may also be part of your treatment plan. Your healthcare provider can help you identify steps that support your overall health and may improve your blood pressure control.

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What challenges have you faced in controlling your blood pressure? Let others know in the comments below.