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Uses

What is atenolol/chlorthalidone used for?

Atenolol/chlorthalidone is commonly used to treat high blood pressure (hypertension). Lowering blood pressure may also lower the risk of heart attack or stroke.

Atenolol/chlorthalidone may also be used for other conditions as determined by your healthcare provider.

How does atenolol/chlorthalidone work (mechanism of action)?

Atenolol/chlorthalidone blocks beta-1 receptors in your heart. These receptors normally bind to hormones called catecholamines. When catecholamines bind to these receptors, it causes your heart to beat harder and faster. Blocking these receptors helps your heart beat more slowly. Atenolol/chlorthalidone also works by increasing how much you pee. It does this by helping the kidneys remove electrolytes, such as sodium (salt), and water from the body. Together, these effects can help lower blood pressure and may reduce your risk for heart attack and stroke.

How is atenolol/chlorthalidone supplied (dosage forms)?

Brands and other names

  • Tenoretic

Dosage forms and strengths

  • 50 mg/25 mg oral tablets
  • 100 mg/25 mg oral tablets

How should I store atenolol/chlorthalidone?

Atenolol/chlorthalidone should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a tightly closed and light-resistant container, in a cool, dry place. Protect from light.

Side Effects

What are the most common side effects of atenolol/chlorthalidone?

The most common side effects of atenolol/chlorthalidone are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Slow heartbeat or bradycardia (see below)
  • Low blood pressure, especially when standing up (see below)
  • Cold feeling in nose, fingers, or toes
  • Dizziness
  • Depression
  • Feeling extremely weak or tired
  • Nausea
  • Shortness of breath
  • Diarrhea
  • Itching
  • Rash
  • Electrolyte changes and increased blood sugar (see below)
  • An increase in how much you pee
  • Muscle pain

There may be other side effects of atenolol/chlorthalidone that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of atenolol/chlorthalidone?

While less common, the most serious side effects of atenolol/chlorthalidone are described below, along with what to do if they happen.

Severe Allergic Reactions. Atenolol/chlorthalidone may cause allergic reactions, which can be serious. Stop taking atenolol/chlorthalidone and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

New or Worsening Heart Failure. Atenolol/chlorthalidone may worsen existing heart failure or cause fluid buildup in your body. For individuals with underlying heart disease or heart damage, atenolol/chlorthalidone can potentially lead to heart failure over time. Tell your healthcare provider right away if you have any of the following symptoms.

  • Shortness of breath or trouble breathing, especially while lying down
  • Swelling in your feet, ankles, or legs
  • Unusually fast weight gain
  • Unusual tiredness

Heart Rate Changes. Atenolol/chlorthalidone can make your heart beat slower than normal (bradycardia). Call your healthcare provider right away if you have any of the following symptoms of bradycardia.

  • Feeling lightheaded, dizziness, or fainting
  • Confusion
  • Feeling weak or easily tired 
  • Chest pain
  • Shortness of breath

Low Blood Pressure with Worsening Kidney Function. Atenolol/chlorthalidone may cause low blood pressure. If you feel faint or dizzy, lie down. Water loss from atenolol/chlorthalidone can lower your blood pressure too much and cause dehydration. Both may lead to problems that are more serious than light-headedness. Poor blood flow to important organs such as your kidneys can occur, especially if you are elderly. Drink enough water to stay hydrated, especially if you have excessive sweating, vomiting, or diarrhea. Get out of bed or from a seated position slowly. Tell your healthcare provider right away if you have any of the following symptoms.

  • Dizziness, feeling lightheaded, or fainting
  • Confusion
  • Feeling weak or tired
  • Sudden weight gain
  • Confusion
  • Reduced need to pee
  • Increased thirst
  • Dark or strong-smelling pee
  • Dry mouth
  • Sunken eyes
  • Headache
  • Fast heartbeat

Breathing Problems. Atenolol/chlorthalidone may cause the muscles around the airways to tighten (bronchospasm) instead of relaxing, which can be serious. Stop using atenolol/chlorthalidone and contact your healthcare provider right away if you have trouble breathing.

Electrolyte Changes and Increased Blood Sugar. Atenolol/chlorthalidone may increase your blood sugar (glucose) levels and cause changes to the levels of certain minerals in your body, called electrolytes. For example, it may cause low potassium levels (hypokalemia), low sodium levels (hyponatremia), low magnesium levels (hypomagnesemia), high calcium levels (hypercalcemia), or low chloride levels (hypochloremia), or high glucose levels (hyperglycemia). These changes can be serious. Your healthcare provider will do bloodwork to check your glucose and electrolyte levels, especially if you take certain other medicines. Keep your appointments to have your blood checked. Call your healthcare provider if you have any of the following symptoms.

  • Weakness
  • Unusual tiredness
  • Muscle cramps or twitching
  • Constipation
  • Nausea, vomiting, or loss of appetite
  • Dizziness
  • Restlessness or irritability
  • Difficulty breathing
  • Confusion or decreased alertness
  • Abnormal heart rhythm
  • Seizures

Severe Skin Reactions. Atenolol/chlorthalidone can cause severe skin reactions called Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) that can lead to death if not treated. If you develop a rash, stop atenolol/chlorthalidone and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms of SJS or TEN.

  • Painful red or purple skin that looks burned and peels off
  • Flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes

Inflammation of the Pancreas (Pancreatitis). Atenolol/chlorthalidone may cause inflammation of the pancreas, which is called pancreatitis. Stop taking atenolol/chlorthalidone and call your healthcare provider right away if you have symptoms of pancreatitis including vomiting or severe pain in the upper part of your belly that travels to your back.

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking atenolol/chlorthalidone. Call your healthcare provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Warnings & Precautions

Who should not use atenolol/chlorthalidone?

Allergies to Ingredients. People who are allergic to any of the following should not take atenolol/chlorthalidone.

  • Tenoretic
  • Atenolol
  • Chlorthalidone
  • Any other medicine known as a sulfonamide (sulfa drug)
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific atenolol/chlorthalidone products they stock.

Bradycardia. Atenolol/chlorthalidone should not be taken if your heart is beating too slow (bradycardia).

Heart Block. Atenolol/chlorthalidone should not be taken if the electrical signals in your heart move too slow (heart block) unless you have a pacemaker.

Severe or Worsening Heart Failure. Atenolol/chlorthalidone should not be taken if your heart failure is severe or getting worse, causing you to feel very tired, have trouble breathing, or swelling in your legs.

Cardiogenic Shock. Atenolol/chlorthalidone should not be taken if you have a life-threatening condition called cardiogenic shock where your heart cannot pump enough blood to the rest of your body.

No Urine Production. Do not take atenolol/chlorthalidone if you are making very little to no pee. This condition is also called anuria.

Very Low Electrolytes. If you have low electrolytes, including low sodium or potassium, atenolol/chlorthalidone may not be safe to take. Your healthcare provider may measure your electrolytes before starting atenolol/chlorthalidone. Low electrolytes are not usually something you can feel, so it is important to make it to your scheduled blood work appointments. 

Untreated Pheochromocytoma. Atenolol/chlorthalidone should not be taken by people with a certain type of adrenal gland tumor, called pheochromocytoma, if it is not being treated.

What should I know about atenolol/chlorthalidone before using it?

Do not take atenolol/chlorthalidone unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share atenolol/chlorthalidone with other people, even if they have the same condition as you. It may harm them.

Keep atenolol/chlorthalidone out of the reach of children.

People who are age 65 or older can be at greater risk for some side effects from atenolol/chlorthalidone. Talk to your healthcare provider about your risks if you are in this age group.

Atenolol/chlorthalidone can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how atenolol/chlorthalidone affects you.

Your skin may be very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds, while you are taking certain drugs, including chlorthalidone. This is called photosensitivity. Use sunscreen and wear a hat and clothes that cover your skin if you need to be in the sunlight.

What should I tell my healthcare provider before using atenolol/chlorthalidone?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if atenolol/chlorthalidone is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Heart problems, including heart failure
  • Breathing problems, including asthma
  • Kidney or liver problems
  • Thyroid problems
  • Pheochromocytoma
  • Persistent or severe diarrhea or vomiting, which can lead to dehydration
  • Low electrolytes, including potassium and sodium
  • Abnormal heart rhythm (arrhythmias)
  • Gout
  • A reduced need to pee

Use Epinephrine to Treat Allergic Reactions. Atenolol/chlorthalidone may lower your response to typical doses of epinephrine when treating an allergic reaction. 

Diabetes. Atenolol/chlorthalidone can decrease early signs of low blood sugar, such as fast heartbeat, and make it more likely for the low blood sugar to be serious, especially for people with diabetes.

Systemic Lupus Erythematosus. Atenolol/chlorthalidone may activate or worsen systemic lupus erythematosus. Tell your healthcare provider if you develop or have a worsening rash, joint pain, fever, or unusual tiredness.

Sulfa Allergy. Some people who have a sulfa allergy may also be allergic to atenolol/chlorthalidone. A sulfa allergy is a rash or more serious reaction to sulfa, or sulfonamide, medicines. Sulfa medicines include sulfamethoxazole, sulfadiazine silver, or sulfasalazine. Tell your healthcare provider if you have any allergies to medicines.

Other Medicines and Supplements. Atenolol/chlorthalidone may interact with other medicines and supplements. Before taking atenolol/chlorthalidone, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how atenolol/chlorthalidone could affect pregnancy or harm an unborn baby, but atenolol can cause harm to an unborn baby if taken during pregnancy. Tell your healthcare provider if you are or plan to become pregnant. If you become pregnant, contact your healthcare provider right away.

Breastfeeding. It is not known if atenolol/chlorthalidone passes into breast milk, but atenolol does. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take atenolol/chlorthalidone while breastfeeding.

Interactions

Does atenolol/chlorthalidone interact with foods or drinks?

There are no known interactions between atenolol/chlorthalidone and foods or drinks. However, since chlorthalidone (one of the active ingredients in atenolol/chlorthalidone) affects electrolytes, it is important to discuss your intake of electrolytes, including sodium and potassium, with your healthcare provider.

Drinking alcohol may increase your risk of experiencing orthostatic hypotension if you are taking atenolol/chlorthalidone. The risk of dizziness may also be increased if you drink alcohol while taking atenolol/chlorthalidone. It is best to limit the amount of alcohol you drink.

Does atenolol/chlorthalidone interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking atenolol/chlorthalidone

  • Any medicine for diabetes
  • Any medicine for high blood pressure
  • Amiodarone or disopyramide, which are medicines for certain heart rhythm problems
  • Lithium, which is a medicine commonly used for certain mental health conditions
  • A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, which are contained in many prescription and OTC products for pain, swelling, and fever
  • Clonidine, which is a medicine used to treat high blood pressure and attention deficit hyperactivity disorder (ADHD)
  • Diltiazem and verapamil, which are medicines used to treat chest pain and high blood pressure
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
  • Other beta-blockers, such as bisoprolol (Zebeta), metoprolol (Lopressor, Toprol XL, and others), or propranolol (Inderal LA, Innopran XL), which are medicines used for certain heart conditions or to reduce blood pressure 

This may not be a complete list of medicines that can interact with atenolol/chlorthalidone. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much atenolol/chlorthalidone?

If you or someone else has taken too much atenolol/chlorthalidone, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of atenolol/chlorthalidone?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.