Blood pressure medications can be lifesavers. But they can also lead to side effects, complicating the adoption of any blood pressure drug regimen. And if someone accidentally or intentionally takes more medication than they're supposed to, the result could be dangerous.
"Any time you take any medication, you are at risk for having side effects," says Willie E. Lawrence Jr., MD, preventive cardiologist and chief medical officer for the Cardiac and Vascular Interventional Group in Dallas. "That's always a possibility."
Common Side Effects of Blood Pressure Medications
Even when taken exactly as prescribed, blood pressure drugs can sometimes trigger the following adverse effects:
- Weakness
- Fatigue
- Dizziness
- Fainting
- A dry cough
- Diarrhea
- Constipation
- Nervousness
- Headaches
- Nausea
- Skin rash
- Erection problems
- Weight changes
That being said, not everyone will experience all, or even any, side effects. Safe use of medications can reduce your risk of side effects.
Side Effects by Drug Class
The various kinds of blood pressure drugs carry different risks.
Diuretics
Sometimes referred to as water pills, diuretics are popular because they effectively help reduce arterial wall pressure by helping the kidneys excrete excess salt (sodium) and water.
Examples include these forms:
- chlorthalidone (HemiClor, Hygroton)
- chlorothiazide
- hydrochlorothiazide (Esidrix)
- indapamide (Lozol)
- metolazone (such as Mykrox)
"If a patient takes a diuretic for high blood pressure control, there's a risk for triggering dehydration," Dr. Lawrence says. Dehydration can increase the risk for issues ranging from minor headache to heat stroke.
Diuretics can also cause excessive urination.
Beta-Blockers
These drugs lower blood pressure by blocking the effects of epinephrine, also known as adrenaline. This reduces your heart rate and blood output.
Side effects of beta-blockers might include the following:
- Insomnia
- Depression
- Cold hands and feet
- Erectile dysfunction
Taking too much of a beta-blocker can result in poisoning.
Examples include the following drugs:
- acebutolol
- atenolol (Tenormin)
- metoprolol (Lopressor)
- bisoprolol (Zebeta)
ACE Inhibitors
ACE inhibitors lower blood pressure by blocking a chemical that causes arterial narrowing. But these drugs can give rise to the following side effects:
- Chronic cough
- A skin rash
- Loss of taste
- Dizziness
- Fainting
- Kidney damage
In addition, taking excessive amounts of an ACE inhibitor can lead to a dangerous buildup of potassium.
Examples of ACE inhibitors include the following:
- benazepril hydrochloride (Lotensin)
- captopril (Capoten)
- enalapril maleate (Vasotec)
- fosinopril sodium (Monopril)
Calcium Channel Blockers
This type of blood pressure medication helps relax the arteries by blocking calcium from clogging the heart and its pathways. By keeping calcium from entering the smooth muscle cells of the heart and arteries, your heart rate reduces and blood pressure comes down. However, these drugs can cause leg swelling, in which case you should consult your doctor.
Examples of calcium channel blockers include the following:
- amlodipine besylate (Norvasc)
- diltiazem hydrochloride (Cardizem CD, Cardizem SR)
- felodipine (Plendil)
- isradipine (DynaCirc)
The Dangers of Incorrect Dosing
But Gregg Fonarow, MD, director of the Ahmanson-UCLA Cardiomyopathy Center, cautions that "excess dosing of blood-pressure-lowering medications can lower blood pressure and cause symptoms like dizziness or passing out. And if blood pressure remains low for a prolonged period, this can damage the kidneys and other organs," he says.
Stick to the recommended dosing as prescribed by your doctor. If you feel the dose is too low and isn’t having the desired effect, a healthcare professional can always gradually increase it to see how you tolerate it.
“If you take any of these blood pressure drugs as prescribed, there is almost zero risk that you will overdose," Lawrence says. "Blood pressure medications are never given on an as-needed basis. You are always instructed to take the same dose of whatever drug you're prescribed every single day. And if you do that, you will stay safe."
