6 Potential Serious Side Effects of Blood Pressure Medications

Medications used to manage hypertension (high blood pressure) are effective and usually well-tolerated. Serious complications are not common and can vary by drug type, but knowing them can help you recognize when something’s wrong and when to seek medical care.

1. Allergic Reactions

Allergic reactions are a rare but serious side effect that can occur with any medication, including those used to treat blood pressure. Allergic reactions can range from mild to severe and life-threatening.

Seek medical attention immediately if you experience symptoms of an allergic reaction, such as hives, difficulty breathing or swallowing, or swelling of the face, lips, tongue, or throat.

2. Hyperkalemia (Too Much Potassium)

Hyperkalemia happens when you have too much potassium in your blood. In many cases, hyperkalemia may not cause noticeable symptoms, or it may cause mild symptoms like fatigue and weakness.

In severe cases, hyperkalemia may cause:

Some high blood pressure medicines are associated with hyperkalemia, including the following single-ingredient drugs as well as combination drugs that contain one of these ingredients:

If you are taking a medication that may cause high potassium levels, your healthcare provider will closely monitor your levels.

3. Electrolyte Imbalances

Electrolytes are minerals that play many important roles, including supporting muscle and nerve function and maintaining water balance in the body. Examples of electrolytes include sodium (salt), potassium, calcium, and magnesium.

If you have an electrolyte imbalance, you may not have any symptoms. Or, depending on which electrolyte is affected, you may experience:

• Weakness
• Tirdeness
• Muscle cramps
• Confusion

Diuretics, or water pills, are commonly used in people with high blood pressure and heart problems. They are known as diuretics, or water pills, because they help the kidneys eliminate salt and water through urine.

Diuretics can also cause you to have low levels of electrolytes, potentially causing:

Examples of diuretics include:

• Loop diuretics like Lasix (furosemide) or Bumex (bumetanide)
• Thiazide diuretics such as hydrochlorothiazide or chlorthalidone

If you are taking a diuretic or any other medication that may affect your electrolytes, your healthcare provider will closely its effects.

4. Angioedema (Swelling)

Angioedema is swelling beneath the skin. In addition to swelling under the skin’s surface, it can also cause hives or swelling on the skin’s surface, notably around the eyes, lips, hands, feet, and throat. They may cause pain and/or itching.

Some drugs, including ACE inhibitors, are linked to angioedema. However, this side effect is rare in people who take ACE inhibitors (occurring in less than 1% of people who take them). Still, since ACE inhibitors are so commonly prescribed, about one-third of all angioedema-related ER visits are due to ACE inhibitors.

If you have symptoms of angioedema—such as swelling around the eyes or mouth—seek medical attention right away.

5. Hypotension (Low Blood Pressure)

Hypotension happens when your blood pressure is too low, and it can cause symptoms like dizziness, headache, and confusion.

More than 70% of people with high blood pressure require two or more medications to control their blood pressure. While an effective approach, it can sometimes cause blood pressure to drop too low. This can cause dizziness and lightheadedness, especially when standing up (this is called orthostatic hypotension), which can increase the risk of falls and injury.

It is very common to need to take more than one medication to control blood pressure levels. If you do, be sure to carefully follow your healthcare provider’s instructions for monitoring blood pressure at home and keep all follow-up appointments.

6. Kidney Problems

ACE inhibitors and ARBs are commonly used to control high blood pressure and protect the kidneys. But in some cases, these types of medicines can cause acute kidney injury (AKI). AKI, previously known as kidney failure, occurs when the kidneys suddenly lose their ability to function properly.

ACE inhibitors or ARBs alone do not commonly cause AKI. The risk is higher when you take an ACE inhibitor or ARB, and you are also dehydrated, or you take your medicine along with a nonsteroidal anti-inflammatory drug (NSAID) or loop diuretic.

If you take an ACE inhibitor, ARB, or any other medicine that can affect the kidneys, your healthcare provider will closely monitor your kidney function.