Queen Buyalos is a pharmacist and freelance medical writer. She takes pride in advocating for cancer prevention, overall health, and mental health education. Queen enjoys counseling and educating patients about drug therapy and translating complex ideas into simple language.

Femi Aremu, PharmD, is a professional pharmacist with experience in clinical and community pharmacy. He currently practices in Chicago, Illinois.

Diuril (chlorothiazide ) is a prescription drug used either alone or in combination with other medications to treat people with hypertension (high blood pressure) and to remove the buildup of excess fluid in the body's tissues (known as edema) from the body commonly caused by kidney, liver, or heart disease. Chlorothiazide is categorized as a thiazide diuretic—a type of diuretic (a water pill) that increases urine flow.

Diuril works within the kidneys by stopping the body from reabsorbing sodium and chloride and helping them flush excess sodium, chloride, and water through urination.

Diuril is available for oral administration as a liquid suspension (a liquid with small pieces of drug) or in the form of an intravenous (IV) injection. However, this article will center on the uses of Diuril as an oral medication.

Brand Name(s): Diuril

Administration Route: Oral, intravenous (IV)

Active Ingredient: Chlorothiazide sodium

Dosage Form(s): Tablet, liquid suspension, powder for solution

The Food and Drug Administration (FDA) approved Diuril to treat people with hypertension (high blood pressure) and edema (the buildup of excess fluid in the body's tissues).

Specifically, Diuril is used either as the primary treatment for hypertension or as an adjunct (supportive) therapy used to help enhance the effectiveness of similar drugs used to treat hypertension and its symptoms.

Comparatively, Diuril is used primarily as an adjunct therapy for edema, a disease often exacerbated by congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy.

It's often recommended that in addition to the usage of Diuril, users make productive lifestyle changes, such as regular exercise and adopting a healthy diet—actions that can help manage hypertension and lessen the effects of edema.

Be sure to shake well before use and follow the directions on your prescription label carefully. Take your medication daily as told by your healthcare provider in one to two divided doses.

When used to treat edema, Diuril may be taken daily or only on certain days of the week. Be sure to take Diuril with either meals or a snack.

This drug may cause you to urinate more often. Take Diuril early in the day to avoid nocturia (frequently waking up throughout the night).

Carefully measure each dose with a measuring device. If you do not have one, ask your healthcare provider to give you one.

Store your medicine at room temperature in a dry place. Do not store it in your bathroom. Protect from harsh light and the potential for freezing.

Additionally, keep Diuril away from children and pets.

Toss away any unused or expired medicine. Do not throw expired medication down the drain, sink, or trash can. Ask your pharmacist about the best ways to get rid of your medication. Check out local take-back programs in your area.

Studies regarding Cmax data (the highest concentration of a drug in the blood), have shown that it takes about two hours to start working and four hours for this drug to peak in your body. Its effects last typically for six to 12 hours.

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

As with all medications, Diuril can cause side effects. Tell your healthcare provider about any side effects you experience while taking this medication.

Tell your healthcare provider if any of these side effects or symptoms do not go away or bother you. Common side effects of Diuril include:

Diuril may also cause the loss of other electrolytes, (a category of essential minerals) including magnesium, hydrogen ions, phosphate, and potassium.

Call your healthcare provider right away if you have serious side effects. Call 911 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:

High blood sugar symptoms: Flushing, confusion, breath that smells like fruit, increased thirst, or passing extensive amounts of urine.

Fluid and electrolyte problems: Muscle pain or weakness, mood changes, tachycardia (abnormal or fast heartbeat), passing out, seizures, or dry eyes and mouth.

Kidney problems: Unable to pass urine, blood in the urine, or change in the amount of urine passed.

Pancreatitis symptoms: Severe back pain and severe abdominal pain.

Additionally, more severe side effects include:

Diuril may also worsen the health condition of people with:

Diuril may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Users should be aware of the following before beginning Diuril:

Pregnancy: ​​​​Due to limited studies regarding the potential for a drug-associated risk of negative developmental outcomes concerning a fetus and the pregnant person, make your healthcare provider aware if you are pregnant or plan on becoming pregnant while taking Diuril.

Breastfeeding: Due to the potential for negative side effects, speak with your healthcare provider to fully weigh the risks and benefits of treatment before breastfeeding on Diuril.

Adults over 65: Despite limited studies on the difference in response between people over 65versus younger people, because the drug is known to be substantially excreted (processed) by the kidney, the risk of negative reactions to this drug may be greater in people with compromised renal (kidney) function.

Because older people are more likely to have decreased kidney function, care should be taken in dose selection, and it may be useful to monitor renal function. 

Pediatric use: There are limited studies on the effectiveness of Diuril in infants and young children. Therefore, speak to your healthcare provider about the potential risks associated with your child taking Diuril.

People who smoke: Smoking can lower Diuril's effectiveness. Try to stop smoking before starting Diuril, and avoid smoking while taking Diuril. Your healthcare provider can help you with this goal.

Take the missed dose once you remember. If it is too close to your next dose, skip the missed dose. Go back to your regular dosing frequency. Do take extra or double the quantity.

Do not take more Diuril than directed on the package label. Overdose symptoms for Diuril may include confusion, seizure, burning or numbing feeling, and vision changes.

However, general side effects associated with a medication-related overdose include:

If you think you or someone else may have overdosed on Diuril, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Diuril, call 911 immediately.

It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Check with your doctor right away if you have any of the following symptoms while taking this medicine: convulsions or seizures; decreased urine; drowsiness; dry mouth; excessive thirst; muscle pains or cramps; nausea or vomiting; increased heart rate or pulse; or unusual tiredness or weakness. These may be symptoms of a condition called hypokalemia or low potassium.

This medicine may cause some people to become dizzy. Do not drive, use machines, or do anything else that could be dangerous if you are dizzy.

Drinking alcoholic beverages may also make the dizziness worse. While you are taking this medicine, be careful to limit the amount of alcohol you drink.

Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests (e.g., tests for parathyroid function) may be affected by this medicine.

Diuril is not appropriate for everyone. You should not take this medication if you are allergic to chlorothiazide or any of the inactive ingredients in Diuril.

Diuril may be used with caution in some people only if the healthcare provider determines it is safe. This also includes people allergic to sulfonamide drugs—a large category of man-made, synthetic drugs used for everything from diabetes to pain relief.

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter (OTC) medicines, and vitamins or supplements. 

Certain medications interact with chlorothiazide, causing more side effects or lowering how well the drugs work. Avoid taking these medications with Diuril:

Other drug interactions may occur with Diuril. Consult your healthcare provider for a complete list of drug interactions.

Other medications used to treat high blood pressure or edema like Diuril include:

Although thiazides are frequently prescribed, chlorothiazide is not used as often.

Hydrochlorothiazide and chlorthalidone are usually the first drugs ordered for people with high blood pressure by a healthcare provider.

In comparison, indapamide and metolazone primarily treat edema in people with heart failure.

This list is a list of drugs also prescribed for high blood pressure or edema. It is not a list of drugs recommended to take with Diuril. In fact, you should not take these drugs together. Ask your healthcare provider if you have questions.

Diuril is prescribed to work either as an adjunct or primary therapy for individuals with high blood pressure or as an adjunct medication for people with edema to enhance the effectiveness of other antihypertensive drugs.

Take the missed dose as soon as you think of it. If it is too close to your next dose, skip the missed dose. Do not double up or take extra amounts.

It takes about two hours to start working and four hours to peak in your body. Its effects last for six to 12 hours.

Store at room temperature in a dry place away from light. Do not store it in your bathroom, and do not freeze it.

Routinely taking your medicine, eating healthy, and living healthy lifestyles are some of the few ways to cope with high blood pressure or heart failure. Watch your diet and let your healthcare provider know before using any OTC product. 

Avoid salt, diet pills, cold medicine, stimulants, some natural products, and non-steroidal anti-inflammatory drugs (NSAIDs), such as Advil (ibuprofen) or Naprosyn (naproxen). Additionally, it's important to check your blood pressure every day. 

And as a final reminder, report any concerns to your healthcare provider, no matter how small you may think it is.

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

Salix Pharmaceuticals. Diuril (chlorothiazide) prescribing information.

Ovung A, Bhattacharyya J. Sulfonamide drugs: structure, antibacterial property, toxicity, and biophysical interactions. Biophys Rev. 2021;13(2):259-272. doi:10.1007/s12551-021-00795-9

Prescribers’ Digital Reference. Chlorothiazide - drug summary.

Reilly RF, Peixoto AJ, Desir GV. The evidence-based use of thiazide diuretics in hypertension and nephrolithiasis. Clin J Am Soc Nephrol. 2010;5(10):1893-1903. doi:10.2215/CJN.04670510

Carter BL, Ernst ME, Cohen JD. Hydrochlorothiazide versus chlorthalidone: evidence supporting their interchangeability. Hypertension. 2004;43(1):4-9. doi:10.1161/01.HYP.0000103632.19915.0E

Dineva S, Uzunova K, Pavlova V, Filipova E, Kalinov K, Vekov T. Comparative efficacy and safety of chlorthalidone and hydrochlorothiazide—meta-analysis. J Hum Hypertens. 2019;33(11):766-774. doi:10.1038/s41371-019-0255-2

By Queen Buyalos, PharmD Queen Buyalos is a pharmacist and freelance medical writer. She takes pride in advocating for cancer prevention, overall health, and mental health education. Queen enjoys counseling and educating patients about drug therapy and translating complex ideas into simple language.

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