- What is atenolol and chlorthalidone, and how does it work (mechanism of action)?
- What brand names are available for atenolol and chlorthalidone?
- Is atenolol and chlorthalidone available as a generic drug?
- Do I need a prescription for atenolol and chlorthalidone?
- What are the side effects of atenolol and chlorthalidone?
- What is the dosage for atenolol and chlorthalidone?
- Which drugs or supplements interact with atenolol and chlorthalidone?
- Is atenolol and chlorthalidone safe to take if I'm pregnant or breastfeeding?
- What else should I know about atenolol and chlorthalidone?
What is atenolol and chlorthalidone, and how does it work (mechanism of action)?
Atenolol/chlorthalidone is a combination of atenolol (Tenormin) and chlorthalidone (Hygroton) used for the treatment of high blood pressure. Atenolol is a beta-adrenergic blocking agent that blocks the effects of adrenergic drugs, for example, adrenaline or epinephrine, on nerves of the sympathetic nervous system. Atenolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Atenolol also reduces the force of contraction of heart muscle and lowers blood pressure. Chlorthalidone is a diuretic (water pill). It works by reducing the kidneys' ability to hold on to salt and water and increasing the kidneys' production of urine (diuresis). It is used to eliminate excess salt and water from the body and to treat high blood pressure. The FDA approved atenolol/chlorthalidone in June 1984.
What are the side effects of atenolol and chlorthalidone?
Side effects of Atenolol/chlorthalidone are similar to side effects form the individual components and are:
- Drowsiness
- Nausea
- Weakness
- Headache
- Loss of electrolytes
- Slow heart rate
- Low blood pressure
- Cold extremities
- Dizziness
- Unusual dreams
- Impotence
- Sun sensitivity
What is the dosage for atenolol and chlorthalidone?
The recommended dose of atenolol/chlorthalidone is one tablet once daily starting with 50 mg/25 mg then increasing to 100 mg/25 mg if blood pressure control is not adequate.
Which drugs or supplements interact with atenolol and chlorthalidone?
- Chlorthalidone can lower blood potassium and magnesium levels because both potassium and magnesium are lost in the urine.
- Chlorthalidone reduces the kidney's ability to eliminate lithium (Lithobid) in the urine. As a result, patients taking chlorthalidone at the same time as drugs containing lithium may develop high levels of lithium and/or lithium toxicity.
- Atenolol can mask the early warning symptoms of low blood sugar (hypoglycemia), and should be used with caution in patients receiving treatment for diabetes. Combining atenolol with other drugs that reduce blood pressure or slow heart rate may lead to excessive blood pressure reduction or low heart rate.

SLIDESHOW
How to Lower Blood Pressure: Exercise and Tips See SlideshowIs atenolol and chlorthalidone safe to take if I'm pregnant or breastfeeding?
Atenolol is excreted in breast milk and may adversely affect the infant. Atenolol/chlorthalidone should be avoided while breastfeeding.
What else should I know about atenolol and chlorthalidone?
What preparations of atenolol and chlorthalidone are available?
Tablets: atenolol 50mg and chlorthalidone 25mg; atenolol 100mg and chlorthalidone 25mg.
How should I keep atenolol and chlorthalidone stored?
Tablets should be stored at room temperature, 15C and 30 C (59 F and 86 F).
Summary
Atenolol and chlorthalidone (Tenoretic) is a combination drug prescribed to treat high blood pressure and abnormally rapid heart rhythms. Side effects, drug interactions, storage, dosing, and pregnancy asfety information should be reviewed prior to taking this medication.
Multimedia: Slideshows, Images & Quizzes
-
Heart Healthy Diet: 25 Foods You Should Eat
What foods are heart healthy? Learn what foods help protect your cardiovascular system from heart attack, coronary heart disease,...
-
What Is High Blood Pressure (Hypertension)? Symptoms, Treatments
What causes high blood pressure (hypertension)? What is normal blood pressure? Know the warning signs and symptoms of high blood...
-
Am I Having a Heart Attack? Symptoms of Heart Disease
Heart attacks symptoms vary greatly for men and women, from anxiety and fatigue to nausea and sweating. Learn the warning signs...
-
High-Fiber Super Foods: Whole Grains, Fruits, & More
Learn about high-fiber foods. From fresh fruits to whole grains, these fiber-rich foods can lower cholesterol, prevent...
-
High Blood Pressure (Hypertension) Quiz: Symptoms, Signs & Causes
Take this quiz and test your IQ of high blood pressure (hypertension), the cardiovascular disease that causes most strokes and...
-
High Cholesterol (Hyperlipidemia) Quiz: Test Your Medical IQ
High cholesterol can be a dangerous condition. Take the Cholesterol Quiz to understand what high cholesterol means in terms of...
-
Picture of Heart Detail
The heart is composed of specialized cardiac muscle, and it is four-chambered, with a right atrium and ventricle, and an...
-
Picture of Heart
The muscle that pumps blood received from veins into arteries throughout the body. See a picture of the Heart and learn more...
-
Food Swaps for Meals and Snacks for Heart Health in Pictures
Explore 10 food swaps for heart-wise dining. Learn what food to buy and how to cook in order to make a big difference for your...
Related Disease Conditions
-
High Blood Pressure (Hypertension)
High blood pressure (hypertension) is a disease in which pressure within the arteries of the body is elevated. About 75 million people in the US have hypertension (1 in 3 adults), and only half of them are able to manage it. Many people do not know that they have high blood pressure because it often has no has no warning signs or symptoms. Systolic and diastolic are the two readings in which blood pressure is measured. The American College of Cardiology released new guidelines for high blood pressure in 2017. The guidelines now state that blood normal blood pressure is 120/80 mmHg. If either one of those numbers is higher, you have high blood pressure. The American Academy of Cardiology defines high blood pressure slightly differently. The AAC considers 130/80 mm Hg. or greater (either number) stage 1 hypertension. Stage 2 hypertension is considered 140/90 mm Hg. or greater. If you have high blood pressure you are at risk of developing life threatening diseases like stroke and heart attack.REFERENCE: CDC. High Blood Pressure. Updated: Nov 13, 2017.
-
Arrhythmias (Abnormal Heart Rhythms)
Heart rhythm disorders vary from minor palpitations, premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, and sinus bradycardia, to abnormal heart rhythms such as tachycardia, ventricular fibrillation, ventricular flutter, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), Wolf-Parkinson-White syndrome, brachycardia, or heart blocks. Treatment is dependent upon the type of heart rhythm disorder.
-
Migraine Headache
Migraine headache is a type of headache associated with a sensitivity to light, smells, or sounds, eye pain, severe pounding on one side of the head, and sometimes nausea and vomiting. The exact cause of migraine headaches is not known. Triggers for migraine headaches include certain foods, stress, hormonal changes, strong stimuli (loud noises), and oversleeping. Treatment guidelines for migraines include medicine, pain management, diet changes, avoiding foods that trigger migraines, staying hydrated, getting adequate sleep, and exercising regularly. Prevention of migraine triggers include getting regular exercise, drinking water daily, reducing stress, and avoiding trigger foods.
-
Things to Know About High Blood Pressure Treatment
High blood pressure (hypertension) means high pressure (tension) in the arteries. Treatment for high blood pressure include lifestyle modifications (alcohol, smoking, coffee, salt, diet, exercise), drugs and medications such as ACE inhibitors, angiotensin receptor blockers, beta blockers, diuretics, calcium channel blockers (CCBs), alpha blockers, clonidine, minoxidil, and Exforge.
Treatment & Diagnosis
- High Blood Pressure FAQs
- High Cholesterol (Hyperlipidemia) FAQs
- Drugs: Buying Prescription Drugs Online Safely
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- Drugs: The Most Common Medication Errors
- Medication Disposal
- Dangers of Mixing Medications
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
Prevention & Wellness

Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Reference: FDA Prescribing Information