Find answers to some frequently asked questions about hydrochlorothiazide oral tablets.
How does hydrochlorothiazide work? And how long does it stay in your system?
How hydrochlorothiazide works to treat high blood pressure is still not fully understood.
The drug causes your body to get rid of more sodium and chloride than usual. (Sodium and chloride are some of your body’s electrolytes.) By doing this, the drug also causes your body to get rid of more water than normal.
This is how hydrochlorothiazide acts as a diuretic and reduces edema (fluid retention).
But it’s also thought that helping your body get rid of salt and water may be how hydrochlorothiazide works against high blood pressure. How it helps lower blood pressure over a long term period is still not fully understood.
Hydrochlorothiazide stays in your system for a few days. Once you stop taking the drug, it should be completely eliminated from your body after 3 or 4 days, at most.
If you have any further questions about how hydrochlorothiazide works or affects your body, ask your doctor or pharmacist.
Is hydrochlorothiazide a diuretic? Does it lose weight?
Yes, hydrochlorothiazide is called a water pill. It is also known as a diuretic. Diuretics help lower blood pressure by working with your body to get rid of extra water and salt.
In studies of hydrochlorothiazide, people did not report weight loss as a side effect. But depending on how the drug works, you may lose weight due to water loss while taking the drug.
That said, hydrochlorothiazide is not prescribed for weight loss. And you shouldn’t take diuretics to try to lose weight because these drugs aren’t approved for that purpose. Keep in mind that weight loss due to water weight loss is not permanent.
If you have any questions about your body weight and about taking hydrochlorothiazide, talk to your doctor or pharmacist. They can suggest ways to help you maintain a body weight that’s right for you.
Does hydrochlorothiazide treat COVID-19?
No, hydrochlorothiazide does not treat COVID-19. The drug is not approved for this use and is not prescribed without label for this condition either. (With off-label use, a drug approved to treat one condition is used to treat another condition.)
A medicine with a similar name, called hydroxychloroquine, has been considered a treatment option for COVID-19. But this drug is also not approved as a treatment option for this condition.
For the latest information on COVID-19, including care options, see the Healthline hub.
What should I know about hydrochlorothiazide versus chlorthalidone?
Hydrochlorothiazide and chlorthalidone have a lot in common. But these drugs also have some differences.
Both drugs are prescribed to treat high blood pressure as well as edema (fluid retention).
Additionally, hydrochlorothiazide and chlorthalidone are also classified as diuretics. More specifically, they are both called thiazide diuretics. They cause your body to get rid of excess sodium and chloride, and also get rid of water.
Hydrochlorothiazide and chlorthalidone can interact with many of the same drugs. These include:
And, the drugs can cause many of the same side effects, including:
Unlike hydrochlorothiazide, chlorthalidone is rarely taken more than once a day.
If you have any further questions about how hydrochlorothiazide compares to chlorthalidone, talk to your doctor or pharmacist. They can tell you more about these medications and recommend the best one for your condition.
Can you suddenly stop taking hydrochlorothiazide?
Talk to your doctor or pharmacist before you stop taking hydrochlorothiazide or any other medicine that has been prescribed for you.
Hydrochlorothiazide is not addictive and not known to cause withdrawal symptoms. (With addiction, your body needs a drug to make you feel normal. Sometimes stopping a drug that is causing addiction can lead to withdrawal symptoms.)
But abruptly stopping hydrochlorothiazide can cause a “rebound” effect. With this effect of hydrochlorothiazide, your blood pressure increases or your body retains more water than usual.
A rebound effect does not occur in everyone who takes hydrochlorothiazide. When it occurs, it tends to go away on its own after a few days. But increased blood pressure or fluid retention can be dangerous for some people.
For this reason, you should not stop taking hydrochlorothiazide unless your doctor specifically tells you that you can. Always talk to your doctor or pharmacist if you are considering stopping any medication, including hydrochlorothiazide.
How much water should you drink while taking hydrochlorothiazide?
It depends. Staying hydrated while taking a diuretic such as hydrochlorothiazide can be tricky.
You should talk to your doctor about this and ask them how much water you should drink while taking hydrochlorothiazide.
In general, you can drink water as if you were not taking hydrochlorothiazide. But your doctor may ask you to limit your fluid intake, depending on the condition you are using to treat hydrochlorothiazide.
Also, because hydrochlorothiazide causes your body to eliminate fluid, it can cause dehydration as a side effect. (With dehydration, you have low fluid levels in your body.) So it’s important that you stay hydrated while taking the medication.
Talk to your doctor or pharmacist about how much water you should drink each day while taking hydrochlorothiazide. They can advise you based on your medical history and your current state of health.