Generic Name: Hydrochlorothiazid Brand Name(s): Generics only. No brands available.


What is hydrochlorothiazide used for?

Hydrochlorothiazide is commonly used to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems.

Hydrochlorothiazide is a water pill (diuretic) that causes you to make more urine. This helps your body get rid of extra salt and water.

This medication also reduces extra fluid in the body (edema) caused by conditions such as heart failure, liver disease, or kidney disease. This can lessen symptoms such as shortness of breath or swelling in your ankles or feet.

Hydrochlorothiazide may be prescribed for other uses; ask your doctor or pharmacist for more information.

How should I take hydrochlorothiazide?

  • Do not crush, break, or chew the tablets/capsules.
  • Swallow tablets/capsules whole with a glass of water.
  • Ask your health care provider any questions you may have about how to use hydrochlorothiazide.

How do I store hydrochlorothiazide?

Hydrochlorothiazide is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store hydrochlorothiazide in the bathroom or the freezer. There may be different brands of hydrochlorothiazide that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush hydrochlorothiazide down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using hydrochlorothiazide?

Consult with your doctor or pharmacist, if:

  • You are pregnant or breastfeeding. This is because, while you are expecting or feeding a baby, you should only take medicines on the recommendation of a doctor.
  • You are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • You have allergy with any of active or inactive ingredients of Hydrochlorothiazide or other medications.
  • You have any other illnesses, disorders, or medical conditions.
  • You have any other types of allergies, such as to foods, dyes, preservatives, or animals.

Taking hydrochlorothiazide may interfere with parathyroid function tests.

Is it safe during pregnancy or breastfeeding?


There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category B, according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk
  • B=No risk in some studies
  • C=There may be some risk
  • D=Positive evidence of risk
  • X=Contraindicated
  • N=Unknown


Not known if crosses into breast milk, avoid using in nursing women.

Always consult your health care provider prior to using this medication if you are pregnant, breastfeeding.


Side effects

What side effects can occur from hydrochlorothiazide?

Here are common side effects:

  • Lower than normal blood pressure (especially when standing up from sitting or lying down)
  • Dizziness
  • Headache
  • Weakness
  • Trouble getting or keeping an erection (erectile dysfunction)
  • Tingling in your hands, legs, and feet

Serious side effects:

  • Severe skin reactions (Stevens-Johnson syndrome and exfoliative dermatitis)
  • Painful skin rash
  • Skin peeling and blisters
  • Fever
  • Mouth sores
  • Kidney failure (weakness, shortness of breath, tiredness, confusion, abnormal heart rate or chest pain, producing less urine than normal, increased swelling in your legs, ankles, or feet)
  • Blurred vision (eye pain, trouble seeing)

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with hydrochlorothiazide?

Hydrochlorothiazide may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

These are interactions when taking hydrochlorothiazide with other medications:

  • Increasing toxicity of lithium.
  • May potentiate orthostatic hypotension with barbiturates and narcotics.
  • Enhancing neuromuscular blocking action of competitive neuromuscular blockers (e.g. atracurium).
  • Increasing hypokalaemic effect with corticosteroids, corticotropin, β2 agonists (e.g. salbutamol).
  • Adding effect with other anti-hypertensives.
  • Potentiation of orthostatic hypotension with barbiturates or opioids.
  • Reducing antihypertensive effect by drugs that cause fluid retention (e.g. corticosteroids, NSAIDs, carbenoxolone).
  • Enhancing nephrotoxicity of NSAIDs.
  • Reducing therapeutic effect of antidiabetics.

Does food or alcohol interact with hydrochlorothiazide?

Hydrochlorothiazide may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with hydrochlorothiazide?

Hydrochlorothiazide may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially diabetes, gout, kidney disease, liver disease, lupus.



The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this medication.

What is the dose of hydrochlorothiazide for an adult?


12.5-50 mg PO once daily.


25-100 mg orally once daily or twice daily; not to exceed 200 mg/day.

Hypertension in heart failure (Off-label)

25 mg orally once daily or twice daily; not to exceed 200 mg/day.

Mild fluid retention in heart failure (off-label)

25 mg orally once daily or twice daily; not to exceed 200 mg/day.


Increased hypotension and side effects in elderly.

Potential for electrolyte imbalance in elderly; monitor serum electrolytes.


12.5-25 mg/day orally; titrated in increments of 12.5 mg/day.

Increased electrolyte disturbances are seen with dosages >50 mg/day.

What is the dose of hydrochlorothiazide for a child?


  • <6 months: 1-3 mg/kg/day PO divided q12hr; not to exceed 37.5 mg/day.
  • 6 months-2 years: 1-2 mg/kg/day PO in single daily dose or divided twice daily; not to exceed 37.5 mg/day.
  • 2-12 years: 1-3 mg/kg/day; not to exceed 3 mg/kg/day (100 mg/day).


  • <6 months: 1-3 mg/kg/day orally divided every 12 hours; not to exceed 37.5 mg/day.
  • 6 months-2 years: 1-3 mg/kg/day orally in single daily dose or divided twice daily; not to exceed 37.5 mg/day.
  • 2-12 years: 1-3 mg/kg/day; not to exceed 3 mg/kg/day (100 mg/day).

How is hydrochlorothiazide available?

Hydrochlorothiazide is available in the following dosage forms and strengths:

  • Oral capsule: 12.5mg hydrochlorothiazide.
  • Oral tablet: 12,5mg; 25mg; 50mg hydrochlorothiazide.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

It is also important to carry a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking with you in case of emergencies.

What should I do if I miss a dose?

If you miss a dose of hydrochlorothiazide, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: December 29, 2016 | Last Modified: January 4, 2017