At a Glance
Diuril (chlorothiazide), taken by mouth, is FDA‑approved to treat edema from heart failure, liver or kidney disease, and to treat hypertension in adults and in pediatric patients.
This is a brand drug with no generic or biosimilar.
Active ingredient: Chlorothiazide.
Administration route: Oral.
Typical oral adult doses range from 500 mg to 1,000 mg per day in one or two doses, with pediatric doses based on body weight as directed by a clinician.
How It Works
- Diuril is a thiazide diuretic that helps your kidneys remove extra salt and water in the urine.
- By lowering the amount of fluid in your blood vessels, it helps reduce swelling (edema) and lowers blood pressure.
- It also slightly changes the balance of certain minerals (like potassium and sodium) in the body, which contributes to its blood-pressure-lowering effect.
Treatment and Efficacy
Approved indications
Diuril is approved to treat edema due to conditions such as congestive heart failure, cirrhosis of the liver, and certain kidney disorders, and to treat high blood pressure, usually as part of combination therapy.
Off-label uses
Clinicians may use thiazide diuretics like chlorothiazide off-label in specific kidney or fluid-balance disorders when other options are unsuitable, generally based on small studies and clinical experience rather than large modern trials.
Efficacy expectations
For edema, increased urination typically begins within hours of a dose and swelling often improves over days; for high blood pressure, meaningful changes can appear within days to weeks, with best effect over several weeks of regular use. Overall blood-pressure-lowering efficacy is similar to other older thiazide diuretics, though longer-acting drugs such as hydrochlorothiazide or chlorthalidone are used more commonly for chronic hypertension.
Dosage and Administration
Typical dosing and how to take
For adults, common oral doses for edema or hypertension total 500–1,000 mg per day taken once or in divided doses; children receive weight-based doses as prescribed. It may be taken with or without food, but taking it earlier in the day (and avoiding late-evening doses) helps reduce nighttime urination.
Special instructions
Take exactly as prescribed and do not change the dose or stop suddenly without medical advice; your clinician may start with a low dose and adjust based on blood pressure, swelling, and lab results, and may combine Diuril with other antihypertensives or diuretics.
Missed dose
If you miss a dose, take it when you remember unless it is almost time for your next dose, in which case skip the missed dose and resume your regular schedule; do not double up doses to make up for one that was missed.
Overdose
In case of suspected overdose—signs may include extreme dizziness, fainting, confusion, severe weakness, or very reduced urination—seek emergency medical attention or contact poison control immediately.
Safety and Side Effects
Common side effects
Common effects include increased urination, mild dizziness or lightheadedness (especially when standing up), headache, and mild stomach upset; these are usually dose-related and often improve as the body adjusts.
Serious or rare adverse effects
Seek immediate medical attention for signs of severe allergic reaction (rash, swelling of face or throat, trouble breathing), severe dizziness or fainting, very low urine output, fast or irregular heartbeat, severe muscle cramps or weakness, confusion, or eye pain or vision changes that may signal a rare eye reaction or severe blood-pressure or electrolyte problems.
Warnings and precautions
Use cautiously or avoid in people with severe kidney disease, inability to make urine, known sulfonamide allergy, or severe electrolyte imbalances; dose adjustments and close monitoring may be needed in liver disease, older adults, and those on other blood-pressure or heart medicines. During pregnancy, thiazide diuretics are generally avoided unless clearly needed; in breastfeeding, small amounts may pass into milk and the benefits and risks should be reviewed with a clinician.
Comparative safety and monitoring
Safety is broadly similar to other thiazide diuretics, with main risks related to low sodium, potassium, or magnesium, high calcium or uric acid, dehydration, and low blood pressure. Patients are often monitored with periodic blood tests for electrolytes and kidney function and with blood-pressure checks; report any suspected side effects to your clinician and, in the U.S., they can be reported to FDA MedWatch.
Interactions and Precautions
Drug and supplement interactions
Diuril can interact with other blood-pressure medicines, other diuretics, lithium, certain antiarrhythmics, digoxin, NSAIDs (such as ibuprofen or naproxen), corticosteroids, and some diabetes medicines, potentially altering blood pressure, kidney function, or electrolytes. Supplements or products containing potassium, magnesium, calcium, or sodium, as well as high-salt or very low-salt diets, can change how well the medicine works or affect safety; alcohol can increase dizziness and blood-pressure lowering.
Precautions and conditions
Use with caution in people with kidney or liver disease, gout or high uric acid, diabetes, lupus, or a history of severe electrolyte problems. Inform your clinician and pharmacist about all prescription and nonprescription drugs, supplements, and herbal products you use before starting Diuril.
Monitoring needs
Regular monitoring may include blood pressure checks; blood tests for electrolytes (especially sodium and potassium), kidney function, and sometimes uric acid or blood sugar; and clinical review of symptoms such as dizziness, cramps, or swelling; additional tests (such as ECG) may be ordered if you are on medicines that affect heart rhythm.
Common Questions and Answers
Q: When will I notice Diuril starting to work?
A: Increased urination can start within hours of a dose, while improvement in swelling may be seen over days and blood pressure usually improves over days to weeks with regular use.
Q: Should I take Diuril in the morning or at night?
A: It is usually taken in the morning (and, if prescribed more than once daily, mid-afternoon) to limit nighttime bathroom trips, unless your clinician gives different instructions.
Q: Do I need blood tests while taking Diuril?
A: Many people have periodic blood tests to check kidney function and levels of electrolytes such as sodium and potassium, especially after dose changes or when taking other medicines that affect these values.
Q: Can I drink alcohol while on Diuril?
A: Small amounts of alcohol may be allowed for some people, but alcohol can increase dizziness and blood-pressure lowering, so it is best to ask your clinician and use caution.
Q: Is Diuril safe to use during pregnancy or breastfeeding?
A: Thiazide diuretics like Diuril are generally avoided in pregnancy and used only if clearly needed, and if you are pregnant or breastfeeding your clinician will help weigh the benefits and risks and may suggest alternative treatments.
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Disposal Guidance
Storage
Store Diuril tablets or suspension at room temperature, away from excess heat and moisture, and keep the bottle tightly closed and out of reach of children and pets.
Disposal
Do not flush the medication down the toilet unless instructed; instead, use a drug take-back program if available or follow local FDA/DEA or community guidelines for disposing of unused or expired medicines.