Uses
What is chlorothiazide used for?
Chlorothiazide is a diuretic, also called a water pill, that is commonly used to reduce edema (fluid retention) caused by the following conditions.
- Congestive heart failure, which is a condition where the heart is not pumping as well as it should
- Liver disease, such as cirrhosis, which can lead to a buildup of fluid in the abdomen (ascites)
- Kidney disease, including protein in the urine (nephrotic syndrome)
- Fluid caused by the use of hormones, such as estrogen or other steroids
Chlorothiazide is also used to treat high blood pressure (hypertension).
Chlorothiazide may also be used for other conditions as determined by your healthcare provider.
How does chlorothiazide work (mechanism of action)?
Chlorothiazide works by increasing how much you pee. It does this by helping the kidneys remove electrolytes, such as sodium (salt), and water from the body.
How is chlorothiazide supplied (dosage forms)?
Chlorothiazide is available as Diuril and generic chlorothiazide in the following dosage form that is taken by mouth.
- 250 mg/5 mL oral suspension
Chlorothiazide is also available in injectable forms.
How should I store chlorothiazide?
Chlorothiazide should be stored at room temperature, between 59 F to 86 F (15 C to 30 C). Do not allow chlorothiazide to freeze. Store in a cool place. Keep tightly closed.
Side Effects
What are the most common side effects of chlorothiazide?
The most common side effects of chlorothiazide are listed below. Tell your healthcare provider if you have any of these side effects that bother you.
- Low blood pressure (see below)
- Electrolyte changes and increased blood sugar (see below)
- An increase in how much you pee
There may be other side effects of chlorothiazide that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of chlorothiazide?
While less common, the most serious side effects of chlorothiazide are described below, along with what to do if they happen.
Low Blood Pressure with Worsening Kidney Function. Water loss from chlorothiazide can lower your blood pressure too much and cause dehydration. Both may lead to problems that are more serious than light-headedness. Poor blood flow to important organs such as your kidneys can occur, especially if you are elderly. Drink enough water to stay hydrated, especially if you have excess sweating, vomiting, or diarrhea. Get out of bed or from a seated position slowly. Tell your healthcare provider right away if you have any of the following symptoms.
- Dizziness, feeling lightheaded, or fainting
- Confusion
- Feeling weak or tired
- Sudden weight gain
- Confusion
- Reduced need to pee
- Increased thirst
- Dark or strong-smelling pee
- Dry mouth
- Sunken eyes
- Headache
- Fast heartbeat
Electrolyte Changes and Increased Blood Sugar. Chlorothiazide may increase your blood sugar (glucose) levels and cause changes to the levels of certain minerals in your body, called electrolytes. For example, it may cause low potassium levels (hypokalemia), low sodium levels (hyponatremia), low magnesium levels (hypomagnesemia), high calcium levels (hypercalcemia), or low chloride levels (hypochloremia), or high glucose levels (hyperglycemia). These changes can be serious. Your healthcare provider will do bloodwork to check your glucose and electrolyte levels, especially if you take certain other medicines. Keep your appointments to have your blood checked. Call your healthcare provider if you have any of the following symptoms.
- Weakness
- Unusual tiredness
- Muscle cramps or twitching
- Constipation
- Nausea, vomiting, or loss of appetite
- Dizziness
- Restlessness or irritability
- Difficulty breathing
- Confusion or decreased alertness
- Abnormal heart rhythm
- Seizures
Severe Allergic Reactions. Chlorothiazide may cause allergic reactions, which can be serious. Stop using chlorothiazide and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching, skin rash, or pale red bumps on the skin called hives
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Severe Skin Reactions. Chlorothiazide can cause severe skin reactions called Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) that can lead to death if not treated. If you develop a rash, stop chlorothiazide and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms of SJS or TEN.
- Painful red or purple skin that looks burned and peels off
- Flat red rash or blisters on your skin, mouth, nose, and genitals
- Red, painful, watery eyes
Inflammation of the Pancreas (Pancreatitis). Chlorothiazide may cause inflammation of the pancreas, which is called pancreatitis. Stop taking chlorothiazide and call your healthcare provider right away if you have symptoms of pancreatitis including vomiting or severe pain in the upper part of your belly that travels to your back.
Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking chlorothiazide. Call your healthcare provider right away if you have any of the following symptoms of liver damage.
- Nausea or vomiting
- Stomach or belly pain
- Fever
- Weakness or unusual tiredness
- Itching
- Loss of appetite
- Light-colored poop
- Dark-colored urine
- Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
Warnings & Precautions
Who should not use chlorothiazide?
Allergies to Ingredients. People who are allergic to any of the following should not use chlorothiazide.
- Chlorothiazide
- Diuril
- Any other medicine known as a sulfonamide (sulfa drug)
- Any of the ingredients in the specific product dispensed
Your pharmacist can tell you all of the ingredients in the specific chlorothiazide products they stock.
No Urine Production. Do not take chlorothiazide if you are making very little to no pee. This condition is also called anuria.
Very Low Electrolytes. If you have low electrolytes, including low sodium or potassium, chlorothiazide may not be safe to use. Your healthcare provider may measure your electrolytes before starting chlorothiazide. Low electrolytes are not usually something you can feel, so it is important to make it to your scheduled blood work appointments.
What should I know about chlorothiazide before using it?
Do not take chlorothiazide unless it has been prescribed to you by a healthcare provider. Take it as prescribed.
Do not share chlorothiazide with other people, even if they have the same condition as you. It may harm them.
Keep chlorothiazide out of the reach of children.
Chlorothiazide can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how chlorothiazide affects you.
People who are age 65 or older can be at greater risk for some side effects from chlorothiazide. Talk to your healthcare provider about your risks if you are in this age group.
Your skin may be very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds, while you are taking certain drugs, including chlorothiazide. This is called photosensitivity. Use sunscreen and wear a hat and clothes that cover your skin if you need to be in the sunlight.
What should I tell my healthcare provider before using chlorothiazide?
Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if chlorothiazide is right for you.
Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.
- Heart failure
- Liver problems
- Kidney problems
- Persistent or severe diarrhea or vomiting, which can lead to dehydration
- Low electrolytes, including potassium and sodium
- Abnormal heart rhythm (arrhythmias)
- Diabetes
- Gout
- Prostate problems
- Asthma
- A reduced need to pee
Systemic Lupus Erythematosus. Chlorothiazide may activate or worsen systemic lupus erythematosus. Tell your healthcare provider if you develop or have worsening rash, joint pain, fever, or unusual tiredness.
Sulfa Allergy. Some people who have a sulfa allergy may also be allergic to chlorothiazide. A sulfa allergy is a rash or more serious reaction to sulfa, or sulfonamide, medicines. Sulfa medicines include sulfamethoxazole, sulfadiazine silver, or sulfasalazine. Tell your healthcare provider if you have any allergies to medicines.
Other Medicines and Supplements. Chlorothiazide may interact with other medicines and supplements. Before using chlorothiazide, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.
Pregnancy. It is not known if or how chlorothiazide could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take chlorothiazide while you are pregnant or trying to get pregnant.
Breastfeeding. Do not take chlorothiazide while you are breastfeeding. Chlorothiazide can pass into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.
Interactions
Does chlorothiazide interact with foods or drinks?
There are no known interactions between chlorothiazide and foods or drinks. However, since chlorothiazide affects electrolytes, it is important to discuss your intake of electrolytes, including sodium and potassium, with your healthcare provider.
It is unknown if drinking alcohol will affect chlorothiazide. The risk of dizziness may be increased if you drink alcohol while taking chlorothiazide. It is best to limit the amount of alcohol you drink.
Does chlorothiazide interact with other medicines (drug interactions)?
Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you are using any of the following before using chlorothiazide.
- A barbiturate, such as phenobarbital, butalbital, or primidone, which is a medicine that may be used to treat insomnia, migraines, or seizures
- An opioid, such as oxycodone, morphine, codeine, or fentanyl, which is a medicine used for certain types of pain
- A medicine for diabetes
- A medicine for high blood pressure
- Cholestyramine or colestipol, which are sometimes used to lower cholesterol or lower bile acid levels
- A corticosteroid, such as prednisone, methylprednisolone, or dexamethasone, which is a medicine for certain inflammatory conditions
- Lithium, which is a medicine commonly used for certain mental health conditions
- A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, which are contained in many prescription and OTC products for pain, swelling, and fever
- Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
- A diuretic, also called a water pill, which is a medicine used to reduce edema (fluid retention) and blood pressure
Overdose/Missed Dose
What should I do if I accidentally use too much chlorothiazide?
If you or someone else has used too much chlorothiazide, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
What should I do if I miss a dose of chlorothiazide?
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.
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