Chlorthalidone | Side Effects, Dosage, Uses & More

Generic Name:

chlorthalidone, Oral tablet

All Brands

  • Thalitone
SECTION 1 of 5

Highlights for chlorthalidone

Oral tablet
1

Chlorthalidone is an oral drug that’s used to treat high blood pressure and edema (fluid retention).

2

Your dose depends on the condition that you’re treating and if you’re taking the brand name drug (Thalitone) or the generic (chlorthalidone).

3

Common side effects include drowsiness, nausea, headache, or increased thirst.

4

You shouldn’t use this drug if you’re not producing any urine (anuria).

5

When you first start taking chlorthalidone, you may urinate more often than normal. This should go away after you’ve been taking the medication for a few weeks.

Drug features

Chlorthalidone is a prescription drug. It comes as a tablet you take by mouth.

Chlorthalidone is available as a brand-name drug called 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. Talk to your healthcare provider to see if the generic will work for you.

Chlorthalidone may be taken in combination with other antihypertensive medications.

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.

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.

See Details

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.

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chlorthalidone Side Effects

Oral tablet

Most Common Side Effects

The more common side effects that can occur with chlorthalidone 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 9-1-1 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
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Chlorthalidone may cause drowsiness.

When you first start taking chlorthalidone, you may urinate more often than normal. This should go away after you’ve been taking the medication for a few weeks.

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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chlorthalidone May Interact with Other Medications

Oral tablet

Chlorthalidone 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.

Alcohol interaction

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

Medications that might interact with this drug

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 digozin 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.

People with kidney disease

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

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.

People with gout

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

People with lupus

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

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.

People with low potassium

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

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.

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.

Women who are breast-feeding

Chlorthalidone may pass into breast milk and cause serious effects in a child who is breast-fed.

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

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.

Allergies

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 9-1-1 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).

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How to Take chlorthalidone (Dosage)

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

What are you taking this medication for?

High blood pressure (hypertension)

Brand: Thalitone

Form: Oral tablet
Strengths: 15 mg

Generic: chlorthalidone

Form: Oral tablet
Strengths: 25 mg, 50 mg
Adult dosage (ages 18–64 years)
  • Brand-name drug (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.

Dose increases: Your doctor may increase your daily dose to 50 mg and then 100 mg if needed.

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.

Fluid retention (edema)

Brand: Thalitone

Form: Oral tablet
Strengths: 15 mg

Generic: chlorthalidone

Form: Oral tablet
Strengths: 25 mg, 50 mg
Adult dosage (ages 18–64 years)
 
  • Brand-name drug (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

Dose increases: Your doctor may increase your daily dose to 50 mg and then 100 mg if needed.

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.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Chlorthalidone 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 9-1-1 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.

For high blood pressure: Chlorthalidone is used for long-term treatment.

For edema: Chlorthalidone is used for short-term or long-term treatment.

Important considerations for taking chlorthalidone
take with food Chlorthalidone should be taken with food
timing Chlorthalidone should be taken in the morning. Take it at the same time each day.
can crush or cut You can crush or cut the tablet
storage Store this medication carefully See Details
refillable Prescription is refillable
travel Travel See Details
self-management Self-management See Details
clinical monitoring Clinical monitoring See Details
diet considerations Your diet See Details
sun sensitivity Sun sensitivity See Details
not usually stocked Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead.
prior authorization Insurance See Details

Store this medication carefully

  • 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.

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 a 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.

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.

What does the pill look like?

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How Much Does chlorthalidone Cost?

Oral tablet

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Lowest price for chlorthalidone

Walmart $12.84
Sams Club $12.84
CVS Pharmacy $13.71
These prices represent the lowest priced national pharmacies for chlorthalidone on GoodRx. They may be lower than your insurance.

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These prices represent the lowest priced national pharmacies for chlorthalidone on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on September 6, 2015

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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