Medications for high blood pressure can help prevent a range of complications, including heart disease and stroke.

According to the American Heart Association, the types of medications a doctor may prescribe are:

This article outlines the various blood pressure medications and their associated side effects and risks.

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Excess salt can cause a buildup of fluid within the blood vessels, which raises blood pressure. Diuretics help the body eliminate excess salt and water by increasing urine output.

There are different types of diuretics. Here are some examples:

  • chlorthalidone (Hygroton)
  • amiloride hydrochloride (Midamar)
  • furosemide (Lasix)

Possible side effects of diuretics include:

People taking diuretics may also experience decreased libido, though this is less common.

Some medications can interact with diuretics, so a person should ensure the doctor knows which other drugs they are taking. Drugs that may interact with diuretics include:

Diuretics may not be suitable for people who tend to become dehydrated quickly. They can also make the following conditions worse:

Beta-blockers reduce blood pressure by blocking the action of hormones in the nervous system, such as epinephrine, also known as adrenaline.

Blocking these hormones slows down the nerve impulses traveling through the heart. As a result, the heart rate slows down and pumps blood less forcefully around the body.

Here are some examples of beta-blockers:

Some side effects of beta-blockers may include:

Less common side effects include:

Some drugs and medications can change the effectiveness of beta-blockers. These include:

Beta-blockers may not be suitable for people with the following conditions or problems:

Angiotensin-converting enzyme (ACE) is an enzyme that causes the body’s blood vessels to narrow, which leads to an increase in a person’s blood pressure.

ACE inhibitors lower blood pressure by blocking ACE, relaxing the blood vessels, and allowing blood to flow more freely.

Examples of ACE inhibitors include:

  • benazepril hydrochloride (Lotensin)
  • fosinopril sodium (Monopril)
  • quinapril hydrochloride (Accupril).

On April 22, 2022, Pfizer issued a voluntary recall of 5 lots of the drug Accupril due to the presence of nitrosamine. Nitrosamine, a known carcinogen with the potential to cause cancer, was found to exist in the drug at levels greater than the Acceptable Daily Intake (ADI) as determined by the FDA. This recall is specific only to a handful of lot numbers and does not affect all Accupril tablets made by Pfizer. If you take Accupril tablets, talk with your pharmacist or doctor and they will help you determine if your medication has been impacted by the recall.

A dry cough is the most common side effect of ACE inhibitors.

Less common side effects include:

Medications that may interact with ACE inhibitors include:

  • diuretics
  • other blood pressure medications
  • medications and supplements containing potassium

People who have any of the following medical conditions should speak with a doctor before taking ACE inhibitors:

ACE inhibitors may also be unsuitable for people who have had a heart attack and those who have received a kidney transplant. People should not take them while pregnant.

Angiotensin II is an enzyme that narrows the blood vessels. Angiotensin II receptor blockers (ARBs) block the enzyme’s path to specific receptors, which allows the blood vessels to remain open.

Examples of these drugs are:

  • eprosartan mesylate (Teveten)
  • irbesartan (Avapro)
  • valsartan (Diovan)

Headaches and dizziness are the most common side effects of ARBs. Less common side effects include:

The following medications can increase or decrease the effect of ARBs:

  • diuretics
  • medications and supplements containing potassium
  • other blood pressure medications
  • some heart medications
  • over-the-counter medicines for allergies, colds, and flu

ARBs may not be suitable for people who have previously had a bad reaction to ACE inhibitors. They may also not be suitable for people with the following conditions:

People should not take these drugs during pregnancy.

Calcium causes the smooth muscles of the heart and arteries to contract more strongly.

Calcium channel blockers slow the entry of calcium into these muscles. This reduces the strength of the contractions and lowers the blood pressure.

There are several calcium channel blockers available, such as:

  • diltiazem hydrochloride (Cardizem)
  • nifedipine (Procardia XL)
  • verapamil hydrochloride (Calan SR)

Common side effects of calcium channel blockers include:

  • tiredness
  • flushing
  • swollen feet or ankles

Less common side effects include:

  • palpitations
  • nausea
  • dizziness
  • shortness of breath
  • upset stomach
  • constipation
  • rash or itchy skin

Drinking grapefruit juice while taking some calcium channel blockers can increase the risk of side effects.

Calcium channel blockers may interact with the following medications and supplements:

  • diuretics
  • other blood pressure medications
  • some heart medications, such as antiarrhythmics and digitalis
  • some eye medications

People taking more than 60 milligrams per day of some calcium channel blockers may experience low blood sugar levels.

Also, calcium channel blockers may not be suitable for people with the following conditions:

  • very low blood pressure
  • heart failure or other conditions affecting the heart or blood vessels
  • kidney or liver disease
  • depression

Certain hormones in the body, such as norepinephrine, can bind to chemical receptors called alpha-receptors. When this happens, the blood vessels narrow, and the heart pumps blood faster, causing a rise in blood pressure.

Alpha-blockers reduce blood pressure by preventing norepinephrine from binding to alpha-receptors. This relaxes the blood vessels, which allows blood to flow more freely.

Examples of alpha-blockers are:

  • doxazosin mesylate (Cardura)
  • prazosin hydrochloride (Minipress)
  • terazosin hydrochloride (Hytrin)

Possible side effects of alpha-blockers include:

  • rapid heart rate
  • a drop in blood pressure when standing up
  • dizziness
  • headaches
  • nausea
  • feeling tired, weak, or lethargic
  • disturbed sleep
  • skin rash or itchiness
  • loss of bladder control in women
  • erectile dysfunction in men

Other substances that lower blood pressure may cause a dangerous drop in blood pressure when taken alongside alpha-blockers. These substances include:

Alpha-blockers may make the following medical conditions worse:

A fall in blood pressure when taking these drugs can lead to faintness and dizziness and a higher risk of falls, which can lead to fractures.

Similar to alpha-blockers, these drugs lower blood pressure by preventing the release of norepinephrine.

Methyldopa is an alpha-2 receptor agonist.

Alpha-2 receptor agonists can cause:

  • tiredness
  • drowsiness
  • dizziness

People should speak with their doctor before using these drugs if they:

A doctor may prescribe a drug with both alpha- and beta-blocker activity. The alpha-blocker activity decreases the narrowing of blood vessels, while the beta-blocker activity slows the heart rate, causing it to pump blood less forcefully.

Doctors may give combined alpha- and beta-blockers in an intravenous (IV) drip to people experiencing a hypertensive crisis. This is when blood pressure rises rapidly to a dangerously high level.

They may also prescribe them for people with a high risk of heart failure.

One example of this type of drug is carvedilol (Coreg).

People may experience the side effects of both alpha- and beta-blockers.

Some types of combined alpha- and beta-blockers may interact with the following medications:

They may also not be suitable for people with:

  • asthma
  • COPD
  • slow heart rate
  • liver disease
  • diabetes

Central agonists lower blood pressure by preventing the brain from sending signals to the nervous system to increase heart rate and constrict blood vessels.

As a result, the heart pumps blood less forcefully, and blood vessels remain open.

Examples of this type of drug are:

  • alpha methyldopa (Aldomet)
  • clonidine (Catapres)
  • guanabenz acetate (Wytensin)
  • guanfacine hydrochloride (Tenex)

Depending on the drug, central agonists can cause the following side effects:

  • feeling faint or weak, especially when standing up
  • drowsiness or lethargy
  • dry mouth
  • fever
  • anemia
  • erectile dysfunction
  • constipation
  • nasal congestion
  • pancreatitis
  • liver disease

The following substances can cause a person’s blood pressure to drop too low when combined with central agonists:

  • alcohol
  • sleeping pills
  • anti-anxiety medications
  • medications classed as benzodiazepines and barbiturates

Central agonists may increase the symptoms of:

Peripheral adrenergic inhibitors (PAIs) block the neurotransmitters in the brain that cause blood vessels to constrict.

Blocking these receptors allows the blood vessels to stay relaxed and open, lowering a person’s blood pressure.

Doctors usually prescribe PAIs only if other blood pressure medications have been ineffective.

Examples of this type of drug are:

  • guanadrel (Hylorel)
  • guanethidine monosulfate (Ismelin)
  • reserpine (Serpasil)

There are several types of PAI, and the side effects differ between types. Possible side effects include:

  • nasal congestion
  • heartburn
  • diarrhea
  • lightheadedness, dizziness, or weakness when standing up
  • fainting
  • low blood pressure
  • erectile dysfunction
  • depression
  • bad dreams

Some PAIs may interact with the following substances:

  • alcohol
  • asthma medications
  • diuretics
  • other blood pressure medications

Anyone who wishes to stop taking tricyclic antidepressants while using a PAI should speak with a doctor. Stopping these medications too quickly while taking certain PAIs can cause a dangerous drop in blood pressure.

Some types of PAIs may not be suitable for people with certain medical conditions. These conditions include:

Vasodilators, or blood vessel dilators, relax and widen the walls of the blood vessels, allowing blood to flow through them more easily. Direct-acting vasodilators specifically target the arteries.

Two types of direct-acting vasodilators are hydralazine hydrochloride (Apresoline) and minoxidil (Loniten).

Minoxidil is the more potent of the two drugs. Doctors usually prescribe it to people with persistent and severe high blood pressure.

Hydralazine hydrochloride may cause the following side effects, which usually subside within a few weeks of beginning treatment:

Possible side effects of minoxidil include:

The following drugs may enhance the effects of vasodilators:

  • diuretics and other blood pressure medications
  • medications for erectile dysfunction, such as sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra)

Taking erectile dysfunction medications in combination with a vasodilator can cause a life threatening drop in blood pressure.

Depending on the type, vasodilators may not be suitable during pregnancy or for people with the following conditions:

Some blood pressure medications are not safe to take during pregnancy. Some medications may be suitable during specific trimesters, while others pose risks throughout pregnancy.

People who are pregnant or planning on getting pregnant should talk with their doctor about treatment options for high blood pressure.

There are many types of blood pressure medications. A doctor will consider the underlying cause of high blood pressure, as well as other health conditions and medications.

Anyone experiencing long-term or intolerable side effects from a blood pressure medication should speak with a doctor, who may prescribe an alternative.