Chlorthalidone 25 Mg Tablet

Store this medicine at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

Chlorthalidone – Uses, Side Effects, and More

Chlorthalidone is used to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. It is also used to reduce extra salt and water in the body caused by conditions such as heart failure, liver disease, and kidney disease. Decreasing extra salt and water in the body helps to decrease swelling (edema) and breathing problems caused by fluid in the lungs. Chlorthalidone is a “water pill” (diuretic). It increases the amount of urine you make, especially when you first start the medication. It also helps to relax the blood vessels so that blood can flow more easily.

How to use Chlorthalidone

Take this medication by mouth with food as directed by your doctor, usually once daily in the morning. It is best to avoid taking this medication within 4 hours of your bedtime to avoid having to get up to urinate. Consult your doctor or pharmacist if you have questions about your dosing schedule.

The dosage is based on your medical condition and response to treatment.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick.

If you also take certain drugs to lower your cholesterol (bile acid-binding resins such as cholestyramine or colestipol), take this product at least 2 hours before or at least 4 hours after these medications.

Tell your doctor if your condition does not improve or if it worsens (such as your blood pressure readings remain high or increase).

Side Effects

Dizziness, lightheadedness, or stomach upset may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication may cause dehydration and electrolyte imbalance. Tell your doctor right away if you have any symptoms of dehydration or electrolyte imbalance, including: extreme thirst, very dry mouth, muscle cramps, weakness, fast/irregular heartbeat, confusion.

Tell your doctor right away if you have any serious side effects, including: fainting, toe/joint pain, signs of kidney problems (such as change in the amount of urine).

Get medical help right away if you have any very serious side effects, including: decrease in vision, eye pain.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US – Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Precautions

Before taking chlorthalidone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, gout, lupus, untreated mineral imbalance (such as low potassium).

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Too much sweating, diarrhea, or vomiting may cause dehydration and increase your risk of dizziness or lightheadedness. Report prolonged diarrhea or vomiting to your doctor. Be sure to drink enough fluids to prevent dehydration unless your doctor directs you otherwise.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

If you have diabetes, this product may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of high blood sugar such as increased thirst/urination. Your doctor may need to adjust your diabetes medication, exercise program, or diet.

This medication may reduce the potassium levels in your blood. Ask your doctor about adding potassium to your diet. A potassium supplement may be prescribed by your doctor.

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

Older adults may be more sensitive to the side effects of this product, especially dizziness.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Consult your doctor before breast-feeding.

Chlorthalidone

Medically reviewed by Drugs.com on Oct 3, 2022. Written by Cerner Multum.

What is chlorthalidone?

Chlorthalidone is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.

Chlorthalidone treats fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, or kidney disorders, or edema caused by taking steroids or estrogen.

Chlorthalidone is also used to treat high blood pressure (hypertension).

Chlorthalidone may also be used for purposes not listed in this medication guide.

Warnings

You should not use chlorthalidone if you are unable to urinate, or if you are allergic to sulfa drugs.

Before taking this medicine

You should not use chlorthalidone if you are allergic to it, or if:

you are unable to urinate; or
you are allergic to sulfa drugs.

Tell your doctor if you have ever had:

kidney disease;
heart failure;
gout;
high cholesterol or triglycerides;
diabetes; or
if you are on a low-salt diet.

Tell your doctor if you are pregnant or plan to become pregnant. Taking chlorthalidone during pregnancy may cause side effects in the newborn baby, such as jaundice (yellowing of the skin or eyes), bruising or bleeding, low blood sugar, or an electrolyte imbalance.

Do not start or stop taking chlorthalidone during pregnancy without your doctor’s advice. Although chlorthalidone may cause side effects in a newborn, having high blood pressure during pregnancy can cause complications such as diabetes or eclampsia (dangerously high blood pressure that can lead to medical problems in both mother and baby). The benefit of treating hypertension may outweigh any risks to the baby.

You should not breastfeed while using chlorthalidone.

How should I take chlorthalidone?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Call your doctor if you are sick with vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking chlorthalidone. This can lead to very low blood pressure, a serious electrolyte imbalance, or kidney failure.

Your blood pressure will need to be checked often. Your blood and urine may both be tested if you have been vomiting or are dehydrated.

chlorthalidone can affect the results of certain medical tests. Tell any doctor who treats you that you are using chlorthalidone.

If you need surgery, tell your surgeon you currently use this medicine.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, weakness, dizziness, drowsiness, extreme thirst, muscle pain, or rapid heartbeats.

What should I avoid while taking chlorthalidone?

Drinking alcohol with chlorthalidone can cause side effects.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Avoid becoming overheated or dehydrated during exercise, in hot weather, or by not drinking enough fluids. Follow your doctor’s instructions about the type and amount of liquids you should drink. In some cases, drinking too much liquid can be as unsafe as not drinking enough.

Chlorthalidone side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Chlorthalidone may cause serious side effects. Call your doctor at once if you have:

a light-headed feeling, like you might pass out;
low sodium–headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
low potassium–leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling;
low magnesium–dizziness, irregular heartbeats, feeling jittery, muscle cramps, muscle spasms, cough or choking feeling; or
kidney problems–little or no urination, swelling in your feet or ankles, feeling tired or short of breath.

Common side effects of chlorthalidone may include:

low blood pressure (feeling light-headed);
kidney problems;
dizziness; or
an electrolyte imbalance (such as low levels of potassium, sodium, or magnesium in your blood).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Chlorthalidone dosing information

Usual Adult Dose for Hypertension:

-Initial dose: 25 mg orally once a day
-Titration: Increase to 50 mg orally once a day if response is inadequate; if response is still inadequate, increase to 100 mg orally once a day, or a second antihypertensive drug (step 2 therapy) may be added
-Maintenance dose: 25 to 100 mg orally once a day
-Maximum dose: 100 mg orally once a day

Use: Hypertension (alone or with another antihypertensive drug)

Usual Adult Dose for Edema:

-Initial dose: 50 to 100 mg orally once a day, or 100 mg orally every other day; some patients may require 150 to 200 mg orally at these intervals
-Maximum dose: 200 mg orally once a day

What other drugs will affect chlorthalidone?

Using chlorthalidone with other drugs that make you light-headed can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Tell your doctor about all your other medicines, especially:

other blood pressure medications;
lithium;
digoxin, digitalis;
insulin or oral diabetes medicine; or
steroid medicine.

This list is not complete. Other drugs may affect chlorthalidone, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Popular FAQ

Research has suggested that taking your blood pressure medication at night instead of in the morning can provide better blood pressure control at night without compromising daytime blood pressure control and reduce your overall risk of dying because of cardiovascular disease by 45%. Continue reading

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Drug class: thiazide diuretics
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