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This is an information resource — not medical advice.

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Thiazide Diuretic (Water Pill)🔒 Prescription only

What Is Hydrochlorothiazide Used For?

Brand names: Microzide, HydroDiuril

Hydrochlorothiazide (HCTZ) is a thiazide diuretic (water pill) used to treat high blood pressure and fluid retention from heart failure or kidney conditions.

What is Hydrochlorothiazide used for?

High blood pressure (hypertension)
Fluid retention (edema)
Heart failure
Kidney stones (calcium type)
Diabetes insipidus

How does Hydrochlorothiazide work?

Hydrochlorothiazide causes the kidneys to remove more sodium and water through urine, reducing fluid volume in blood vessels and lowering blood pressure.

Dosage information

💊Available forms

12.5mg capsules
25mg tablets
50mg tablets

📏Typical dosage

Usually 12.5–50mg once daily in the morning. Take in the morning to avoid nighttime urination.

⚠️ Dosage varies by individual. Always follow your doctor's or pharmacist's instructions — never self-dose based on general information.

Side effects

Common

Increased urination
Dizziness when standing
Low potassium levels
Muscle cramps
Increased thirst
Sun sensitivity

⚠️ Serious — contact your doctor

Severe low potassium (muscle weakness, irregular heartbeat)
Low sodium
Elevated blood sugar
Gout attacks

Important warnings

Take in the morning to avoid waking at night

May need potassium monitoring — don't self-supplement without testing

Can raise blood sugar — monitor if diabetic

Increases sun sensitivity — use sunscreen

Drug interactions

These substances may interact with Hydrochlorothiazide. This is not a complete list — always tell your doctor and pharmacist ALL medications and supplements you take.

NSAIDs (reduce diuretic effect)Lithium (toxic levels)Digoxin (low potassium increases toxicity)Diabetes medicationsOther blood pressure medications

Pregnancy & breastfeeding

🤰 Use with caution — discuss with your doctor

Always consult your doctor or obstetrician before taking any medication during pregnancy or while breastfeeding.

Frequently asked questions

What is hydrochlorothiazide used for?

It treats high blood pressure and fluid retention by causing the kidneys to remove excess salt and water.

Why does hydrochlorothiazide cause low potassium?

HCTZ causes the kidneys to excrete more potassium. Low potassium causes muscle cramps, weakness, and irregular heartbeat. Your doctor may recommend potassium-rich foods or supplements.

Should I take hydrochlorothiazide in the morning?

Yes — always take it in the morning. Since it increases urination, taking it at night disrupts sleep.

Can hydrochlorothiazide raise blood sugar?

Yes — it can slightly raise blood sugar. People with diabetes or prediabetes should monitor more closely.

How much water should I drink while taking it?

Stay well hydrated throughout the day but avoid excessive intake. Dehydration is a risk especially in hot weather or during exercise.

Related medications

💊LisinoprilACE Inhibitor 💊AmlodipineCalcium Channel Blocker 💊AtorvastatinStatin (HMG-CoA reductase inhibitor)💊MetoprololBeta-Blocker

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This is an information resource — not medical advice.

🚨 If you are experiencing a medical emergency or think you may have taken too much of a medication, call emergency services (911 in the US) or go to your nearest emergency room immediately.

Information on this page is sourced from general pharmaceutical references and is provided for educational purposes only. Drug information may change — always verify with your pharmacist or prescriber. PillCodex.com is not affiliated with any pharmaceutical company.