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Chlorthalidone, Oral Tablet

Highlights for chlorthalidone

  1. Chlorthalidone oral tablet is available as a generic drug and a brand-name drug. Brand name: Thalitone.
  2. Chlorthalidone only comes as a tablet you take by mouth.
  3. This drug is used to treat high blood pressure and edema (fluid retention).
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About

What is chlorthalidone?

Chlorthalidone is a prescription drug that’s available as the brand-name drug Thalitone. It’s also available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand.

Chlorthalidone only comes as a tablet you take by mouth.

Why it's used

Chlorthalidone is used to treat high blood pressure. It’s also used to treat edema. This is swelling caused by fluid buildup in your body. Edema may be caused by conditions such as heart, liver, or kidney disease.

Chlorthalidone may be taken in combination with other blood pressure medications.

How it works

Chlorthalidone belongs to a class of drugs called antihypertensives/diuretics. A class of drugs refers to medications that work similarly. They’re often used to treat similar conditions.

Chlorthalidone makes your body get rid of extra water and salt through the urine. This helps lower blood pressure. It also helps decrease fluid buildup, which reduces swelling.

Side effects

Chlorthalidone side effects

Chlorthalidone oral tablet may cause drowsiness. It may also cause other side effects.

More common side effects

The more common side effects that can occur with chlorthalidone oral tablet include:

  • stomach problems, such as:
    • nausea
    • vomiting
    • stomach cramping
    • diarrhea
    • constipation
    • loss of appetite
  • dizziness
  • headache
  • increased thirst

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • sore throat and fever
  • unusual bleeding or bruising
  • severe skin rash with peeling skin
  • trouble breathing or swallowing
  • reduced potassium levels. Symptoms can include:
    • extreme thirst
    • tiredness
    • drowsiness
    • restlessness
    • muscle pains or cramps
    • nausea or vomiting
    • increased heart rate

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

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Interactions

Chlorthalidone may interact with other medications

Chlorthalidone oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with chlorthalidone are listed below.

Blood pressure drugs

When chlorthalidone is taken with other medications that lower your blood pressure, your blood pressure may become dangerously low. These drugs include:

  • angiotensin-converting enzyme (ACE) inhibitors, such as:
    • benazepril
    • captopril
    • cilazapril
    • enalapril
    • enalaprilat
    • fosinopril
    • imidapril
    • moexipril
    • perindopril
    • quinapril
    • ramipril
    • trandolapril
  • angiotensin II receptor blockers (ARBs), such as:
    • irbesartan
    • losartan
    • olmesartan
    • telmisartan
    • valsartan
  • beta-blockers, such as:
    • acebutolol
    • arotinolol
    • atenolol
    • betaxolol
    • bisoprolol
    • esmolol
    • metoprolol
    • nadolol
    • nebivolol
    • penbutolol
    • pindolol
    • propranolol
    • timolol (systemic)
  • calcium channel blockers, such as:
    • amlodipine
    • felodipine
    • nicardipine
    • nifedipine
  • loop diuretics, such as:
    • bumetanide
    • furosemide
    • indapamide
    • torsemide
  • potassium-sparing diuretics, such as:
    • eplerenone
    • spironolactone
    • triamterene

Diabetes drugs

Your doctor may need to adjust the dose of your diabetes medication. Chlorthalidone may keep some diabetes drugs from working well. These drugs include:

  • pramlintide
  • metformin
  • exenatide
  • liraglutide
  • lixisenatide
  • saxagliptin
  • sitagliptin
  • insulin
  • nateglinide
  • repaglinide
  • glimepiride
  • glipizide
  • glyburide
  • canagliflozin
  • dapagliflozin
  • empagliflozin
  • pioglitazone
  • rosiglitazone

Other drugs

Digoxin is used to treat certain heart conditions, such as irregular heart rhythms or heart failure. Taking digoxin with chlorthalidone may change the amount of electrolytes in your blood. Your doctor will monitor your electrolytes closely and adjust your medication doses if needed.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Other warnings

Chlorthalidone warnings

This drug comes with several warnings.

Allergy warning

Chlorthalidone can cause a severe allergic reaction. Symptoms include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it or sulfa drugs. Taking it again could be fatal (cause death).

Alcohol interaction

Using alcohol while taking chlorthalidone can increase your risk of dizziness.

Warnings for people with certain health conditions

For people with kidney disease: Chlorthalidone can make your kidney problems worse. Talk with your doctor about whether taking this drug is safe for you.

For people with liver disease: Chlorthalidone can cause changes in your fluid and electrolyte levels. This may even lead to coma. Talk with your doctor about whether taking this drug is safe for you.

For people with gout: This drug may cause gout episodes. Before taking this medication, make sure your doctor knows that you have gout.

For people with lupus: Chlorthalidone may make your condition worse. Before taking this medication, make sure your doctor knows that you have lupus.

For people with allergies or asthma: Chlorthalidone can cause a sensitivity reaction. Before taking this medication, make sure your doctor knows that you have allergies or asthma.

For people with low potassium: This drug can cause low potassium levels. If you already have low potassium levels, your potassium could become too low.

For people with diabetes: Drugs used to treat diabetes may not work as well when taken with chlorthalidone. This could cause higher blood sugar levels. Your doctor may adjust the dose of your diabetes medication.

Warnings for other groups

For pregnant women: Chlorthalidone is a pregnancy category B drug. That means two things:

  1. Studies of the drug in pregnant animals haven’t shown risk to the fetus.
  2. There aren’t enough studies done in pregnant women to show the drug poses a risk to the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. Chlorthalidone should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

For women who are breastfeeding: Chlorthalidone may pass into breast milk and cause serious effects in a child who is breastfed.

You and your doctor may need to decide if you’ll take chlorthalidone or breastfeed.

For seniors: Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

For children: This medication hasn’t been studied in children. It shouldn’t be used in people under the age of 18 years.

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Dosage

How to take chlorthalidone

This dosage information is for chlorthalidone oral tablet. All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Forms and strengths

Generic: Chlorthalidone

  • Form: oral tablet
  • Strengths: 25 mg, 50 mg

Brand: Thalitone

  • Form: oral tablet
  • Strengths: 15 mg

Dosage for high blood pressure (hypertension)

Adult dosage (ages 18–64 years)

  • Thalitone:
    • Typical starting dose: 15 mg taken by mouth once per day.
    • Dose increases: Your doctor may increase your daily dose to 30 mg and then to 45–50 mg.
  • Generic chlorthalidone:
    • Typical starting dose: 25 mg taken by mouth once per day.

Child dosage (ages 0–17 years)

This medication hasn’t been studied in children. It shouldn’t be used in people under the age of 18 years.

Senior dosage (ages 65 years and older)

Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

Warnings

For high blood pressure: If your blood pressure isn’t controlled on the 50-mg dose of the brand name drug (Thalitone) or the 100-mg dose of generic chlorthalidone, your doctor will likely give you a second blood pressure medication.

Dosage for fluid retention (edema)

Adult dosage (ages 18–64 years)

  • Thalitone:
    • Typical starting dose: 30–60 mg taken by mouth once per day, or 60 mg taken every other day. Some people may need 90–120 mg taken once per day or every other day.
    • Maximum dose: 120 mg per day
  • Generic chlorthalidone:
    • Typical starting dose: 50–100 mg taken by mouth once per day, or 100 mg taken every other day. Some people may need 150–200 mg taken once per day or every other day.
    • Maximum dose: 200 mg per day

Child dosage (ages 0–17 years)

This medication hasn’t been studied in children. It shouldn’t be used in people under the age of 18 years.

Senior dosage (ages 65 years and older)

Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

Warnings

For high blood pressure: If your blood pressure isn’t controlled on the 50-mg dose of the brand name drug (Thalitone) or the 100-mg dose of generic chlorthalidone, your doctor will likely give you a second blood pressure medication.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.

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Take as directed

Take as directed

For high blood pressure, chlorthalidone oral tablet is used for long-term treatment. For edema, it is used for short-term or long-term treatment. This drug comes with serious risks if you don't take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all:

  • For high blood pressure: Your blood pressure may stay high. This raises your risk for heart attack or stroke.
  • For edema: Your swelling and fluid buildup won’t decrease. This can lead to serious problems, such as pain, infections, leg ulcers, or blood clots.

If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much: If you take too much chlorthalidone, you may have these symptoms:

  • nausea
  • weakness
  • dizziness
  • extreme thirst
  • confusion
  • seizures

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.

What to do if you miss a dose: If you forget to take your dose, take it as soon as you remember. If it’s just a few hours until the time for your next dose, then wait and only take one dose at that time. Never try to catch up by taking two doses at once. This could cause serious side effects.

How to tell if the drug is working: For high blood pressure: Your blood pressure should go down. Your doctor can check your blood pressure, or you can check it at home using a blood pressure monitor.

For edema: Your swelling or fluid retention should decrease.

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Important considerations

Important considerations for taking chlorthalidone

Keep these considerations in mind if your doctor prescribes chlorthalidone oral tablet for you.

General

  • Chlorthalidone should be taken with food.
  • Chlorthalidone should be taken in the morning. Take it at the same time each day.
  • You can crush or cut the tablet.
  • Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead.

Storage

  • Brand-name drug, Thalitone: Store it below 86°F (30°C).
  • Generic chlorthalidone: Store it from 68–77°F (20–25°C).
  • Don’t freeze chlorthalidone.
  • Keep it away from light.
  • Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Refills

A prescription for this medication is refillable. You shouldn’t need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

You may need to check your blood pressure at home. You should keep a log with the date, time of day, and your blood pressure readings. Bring this log with you to your doctor appointments. You may need to buy a blood pressure monitor. These are available at most pharmacies.

Clinical monitoring

While being treated with chlorthalidone, your doctor will check your blood pressure. Your doctor may also do blood tests to check your potassium level.

Your diet

Your doctor may have you follow a specific diet, such as a low-salt or high-potassium diet. Foods high in potassium include prunes, bananas, and orange juice.

Sun sensitivity

Chlorthalidone may make your skin more sensitive to sunlight. You should wear protective clothing, sunscreen, and limit time out in the sun while you’re taking this drug.

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Alternatives

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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