Key takeaways:
Hydrochlorothiazide (Microzide) is a water pill (diuretic). It treats high blood pressure and fluid buildup.
The typical hydrochlorothiazide dosage for adults ranges from 25 mg to 100 mg daily. It can be taken as a single dose or divided in two doses. A child’s hydrochlorothiazide dosage is based on their weight and age.
Missing one dose of hydrochlorothiazide won’t cause major issues. But missing too many doses in a row could cause your blood pressure to spike or increase fluid buildup.
Talk to your pharmacist if you’re having trouble remembering to take hydrochlorothiazide. They can offer tips, like using a pill box or medication reminder app.
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If you have high blood pressure or fluid buildup, you may be prescribed hydrochlorothiazide (Microzide). This common medication, sometimes called HCTZ, is a type of diuretic (water pill). It’s part of a group of diuretics called thiazides. Hydrochlorothiazide causes you to pee more frequently, removing water and electrolytes from the body.
If you’re prescribed hydrochlorothiazide, you’ll receive instructions for how to take it. Taking the right hydrochlorothiazide dosage will help you get the most out of your medication.
What’s the typical hydrochlorothiazide dosage for adults?
Your hydrochlorothiazide dosage will depend on what you’re treating. It comes as an oral tablet and capsule. It’s usually taken by mouth one to two times a day.
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You can take hydrochlorothiazide with or without food. But if you can, avoid taking it in the evening. Hydrochlorothiazide will cause you to pee more frequently. So taking it too close to bedtime can interrupt your sleep. Ask your prescriber what time of day you should take this medication, especially if you’re taking it more than once a day.
Your dosage may be adjusted depending on several factors, like how the medication impacts your blood pressure, fluid balance, and electrolyte levels. Your prescriber may ask you to check your blood pressure at home. They’ll also ask you how often you’re peeing, and check your electrolyte levels periodically.
Fluid buildup dosage
Hydrochlorothiazide tablets are FDA approved to treat fluid buildup (edema). Edema is a symptom of several health conditions, including heart failure and kidney disease. Hydrochlorothiazide can help remove excess fluid from the body so your organs don’t have to work as hard.
The typical hydrochlorothiazide dosage for fluid buildup is 25 mg to 100 mg once or twice daily. In some situations (like heart failure), your prescriber may ask you to take up to 200 mg per day.
Some people don’t need to take hydrochlorothiazide daily. It depends on how severe your edema is and whether hydrochlorothiazide is causing side effects, particularly electrolyte imbalances. So follow your prescriber’s instructions closely for how to take hydrochlorothiazide.
Good to know: A group of medications called loop diuretics are typically first-choice diuretics for heart failure and kidney disease. A common loop diuretic is furosemide (Lasix). These diuretics are more effective at getting rid of excess fluid from the body. In some cases, thiazides may be added to loop diuretics if you need to reduce your blood pressure further or get rid of more fluid.
High blood pressure dosage
Hydrochlorothiazide is a first-choice medication for high blood pressure (hypertension). The typical dosage is 25 mg to 50 mg once daily. Your care team may start you with 12.5 mg to 25 mg daily, then increase your dose up to 50 mg daily if your blood pressure is still high.
Doses greater than 50 mg per day generally aren’t recommended for hypertension. That’s because benefits from higher doses don’t usually outweigh the extra risk from side effects like dizziness, electrolyte imbalances, and headache.
What’s the typical hydrochlorothiazide dosage for children?
Hydrochlorothiazide tablets can be used to treat hypertension and edema in children. If your child takes hydrochlorothiazide, the dosage will be based on their weight and age:
Younger than 6 months: 1 mg to 2 mg/kg per day as a single dose or divided into two doses. Up to 3 mg/kg per day divided into two doses may be prescribed. The maximum dosage is 37.5 mg per day.
6 months to 2 years: 1 mg to 2 mg/kg per day as a single dose or divided into two doses. The total daily dose should not exceed 37.5 mg.
2 to 12 years old: 1 mg to 2 mg/kg per day as a single dose or divided into two doses. The maximum dosage is 100 mg per day.
Of note, hydrochlorothiazide capsules aren’t approved for use in children.
Are there any dosage adjustments for medical conditions?
If you have kidney or liver problems, you may need a lower hydrochlorothiazide dose. But in general, most people with kidney or liver problems can take this medication. In fact, hydrochlorothiazide is often used in people with kidney disease.
However, if you have severe kidney disease, hydrochlorothiazide can cause nitrogen to build up in your body (azotemia). So your prescriber may check your kidney function while you’re taking hydrochlorothiazide to monitor for potential problems.
Additionally, if you have severe liver damage, you’re at greater risk of fluctuating fluid and electrolyte levels in the body. Hydrochlorothiazide could potentially make this worse (although loop diuretics are often used to treat liver damage with increased fluid in the abdomen).
Good to know: Hydrochlorothiazide may interact with other medications you take. So give your prescriber and pharmacist an updated medication list before you start taking it, and include prescription and over-the-counter products on the list. This will help your healthcare team check for drug interactions.
What happens if you miss a dose of hydrochlorothiazide?
Missing a dose of hydrochlorothiazide isn’t likely to cause major problems. You can take the missed dose as soon as you remember. But if it’s close to your next scheduled dose, skip the missed dose and resume your regular regimen.
If you miss several doses in a row, your blood pressure may spike or fluid buildup may worsen. Consider using a medication reminder app or pill organizer to help you remember your doses. If you’re still having trouble remembering, talk to your prescriber and pharmacist about other methods that may help.
What should you do if you take too much hydrochlorothiazide?
If you take too much hydrochlorothiazide, check in with your healthcare team for what to do next. In many cases, accidentally taking an extra dose of hydrochlorothiazide won’t cause severe problems. Still, you may have more side effects, like dizziness, weakness, and headaches.
Taking large amounts of hydrochlorothiazide is more serious. It can cause low electrolyte levels, dehydration, and extremely low blood pressure. Abnormal heart rhythms can also occur.
If you’ve taken too much hydrochlorothiazide, contact Poison Control at 1-800-222-1222 or a healthcare professional as soon as possible (even if you’re not sure how much you took). However, if you’re experiencing symptoms like extreme dizziness or vomiting, call 911 or go to the nearest emergency room.
How to save on hydrochlorothiazide
There are ways to save on hydrochlorothiazide, which is available as a lower-cost generic medication. You may be able to save over 80% off the average retail price at certain pharmacies with a free GoodRx discount. The price of generic hydrochlorothiazide may be as low as $3.00.
The bottom line
Hydrochlorothiazide (Microzide) is a common diuretic (water pill) used to treat fluid buildup and high blood pressure. Typical hydrochlorothiazide doses for adults range from 25 mg to 100 mg daily as a single dose or divided into two doses. For children, hydrochlorothiazide dosages are based on weight.
Depending on how your body responds to hydrochlorothiazide, your prescriber may adjust your dose periodically. They may ask you to check your blood pressure at home and monitor how often you're peeing. They may also ask you to check your electrolyte levels periodically to make sure they’re within normal limits.
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References
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Jo, W., et al. (2023). Therapeutic roles of thiazides and loop diuretics in blood pressure control and renal protection against chronic kidney disease. Clinical Hypertension.
Kennelly, P., et al. (2020). Diuretic therapy in congestive heart failure. Acta Cardiologica.
MedlinePlus. (2021). Hydrochlorothiazide.
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