Generic Name: Chlorthalidone (klor-THAL-ih-dohn)Brand Name: Thalitone

Chlorthalidone is used for:

Treating high blood pressure. It may be used along with other medicines to treat fluid retention caused by certain conditions (eg, heart failure, liver or kidney problems) or medicines (eg, corticosteroids, estrogens). It may also be used for other conditions as determined by your doctor.

Chlorthalidone is a thiazide-like diuretic. It works by increasing elimination of sodium and potassium in the urine, which causes more water to be eliminated.

Do NOT use Chlorthalidone if:

  • you are allergic to any ingredient in Chlorthalidone , thiazides (eg, hydrochlorothiazide) or related diuretics, or any other sulfonamide-like medicine (eg, sulfisoxazole)
  • you are unable to urinate

Contact your doctor or health care provider right away if any of these apply to you.

Before using Chlorthalidone :

Tell your health care provider if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have gout, liver disease, low blood levels of potassium or sodium, kidney disease, or lupus
  • if you have a history of allergy or bronchial asthma

Some MEDICINES MAY INTERACT with Chlorthalidone . Tell your health care provider if you are taking any of the following medicines.

  • Diazoxide, digitalis glycosides (eg, digoxin), ketanserin, or lithium because their actions and the risk of their side effects may be increased by Chlorthalidone

This may not be a complete list of all interactions that may occur. Ask your health care provider if Chlorthalidone may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Chlorthalidone :

Use Chlorthalidone as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Chlorthalidone by mouth with food, preferably in the morning.
  • Chlorthalidone will increase urination. If you are taking 1 dose of Chlorthalidone daily, take it in the morning to prevent this from affecting your sleep.
  • If you miss a dose of Chlorthalidone , take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Chlorthalidone .

Important safety information:

  • Chlorthalidone may cause dizziness or lightheadedness. These effects may be worse if you take it with alcohol or certain medicines. Use Chlorthalidone with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Chlorthalidone may cause dizziness, lightheadedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
  • Chlorthalidone may cause you to become sunburned more easily. Avoid the sun, sunlamps, or tanning booths until you know how you react to Chlorthalidone . Use a sunscreen or wear protective clothing if you must be outside for more than a short time.
  • Patients who take medicine for high blood pressure often feel tired or run down for a few weeks after starting treatment. Be sure to take your medicine even if you may not feel "normal." Tell your doctor if you develop any new symptoms.
  • Your doctor may have also prescribed a potassium supplement for you. If so, follow the dosing carefully. Do not start taking additional potassium on your own or change your diet to include more potassium without first checking with your doctor.
  • Lab tests, including liver function, kidney function, and electrolytes, may be performed while you use Chlorthalidone . These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
  • Chlorthalidone should be used with extreme caution in CHILDREN; safety and effectiveness in children have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Chlorthalidone while you are pregnant. Chlorthalidone is found in breast milk. Do not breast-feed while taking Chlorthalidone .

Possible side effects of Chlorthalidone :

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; dizziness; headache; lightheadedness, especially when sitting up or standing.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); drowsiness; dry mouth; impotence; inflammation of the pancreas; muscle pain or cramps; nausea; rapid or irregular heartbeat; rash or itching; restlessness; unusual thirst; unusual tiredness or weakness; vomiting; yellowing of the skin or eyes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects at

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (, or emergency room immediately. Symptoms may include confusion; dizziness; dry mouth; excessive urination followed by a decrease in amount of urine; muscle cramps; nausea; vomiting; weak or irregular heartbeat.

Proper storage of Chlorthalidone :

Store Chlorthalidone at room temperature, between 68 and 77 degrees F (20 and 25 degrees C). Brief storage at temperatures between 59 and 86 degrees F (15 and 30 degrees C) is permitted. Store away from heat, moisture, and light. Do not store in the bathroom. Keep Chlorthalidone out of the reach of children and away from pets.

General information:

  • If you have any questions about Chlorthalidone , please talk with your doctor, pharmacist, or other health care provider.
  • Chlorthalidone is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.

This information is a summary only. It does not contain all information about Chlorthalidone . If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

  • Chlorthalidone Prescribing Information (FDA)
  • Chlorthalidone Professional Patient Advice (Wolters Kluwer)
  • Chlorthalidone Detailed Consumer Information (PDR)
  • chlorthalidone Advanced Consumer (Micromedex) - Includes Dosage Information
  • chlorthalidone Concise Consumer Information (Cerner Multum)
  • Thalitone Prescribing Information (FDA)