Hydrochlorothiazide is a prescription diuretic, or “water pill,” that is used to treat high blood pressure (hypertension) and reduce edema (excess fluid and swelling) in the body related to conditions such as congestive heart failure, liver diseases like cirrhosis, and kidney issues like nephrotic syndrome. It may also be used to relieve fluid retention caused by certain medications, such as corticosteroids or estrogen therapy.
The Wellness Collective
What to Know About Hydrochlorothiazide
Reviewed by Ashley Robinson, PharmD, Pharmacy Manager for TelyRx
Table of Contents
how does Hydrochlorothiazide work?
Hydrochlorothiazide works by encouraging your kidneys to filter out and remove excess water and electrolytes — specifically sodium, chloride, and potassium — from the body through urination. This has the effect of making you urinate more often. As a result, your body retains less fluid, which can lower your blood volume, blood pressure, and swelling. Hydrochlorothiazide may also enable blood to flow more easily through the blood vessels, further reducing blood pressure.
The diuretic effects of hydrochlorothiazide may kick in within two hours of taking a dose, and last up to 12 hours. Significant changes in blood pressure may take several days to weeks to become noticeable.
drug facts
| Common Brands | Microzide, Esidrix, HydroDiuril, Oretic, Zide |
|---|---|
| Drug Class | Thiazide diuretic |
| Generic Status | Generic version of Microzide |
| Availability | Prescription Only |
dosing
Note: Dosing information below is educational only. Your prescribing physician will determine your specific dose based on your individual health needs.
Hydrochlorothiazide is an oral medication available in capsule and tablet forms. Dosage strengths include 12.5 mg, 25 mg, and 50 mg. The recommended dose of hydrochlorothiazide depends on why you’re taking it.
- High Blood Pressure – The recommended starting dose is 25 mg taken by mouth once daily. Older adults may be prescribed a lower starting dose of 12.5 mg. Depending on your response to the medication, your healthcare provider may adjust this down or up to 50 mg daily, which can be taken as a single dose or divided into two doses.
- For Edema (Fluid Buildup) – The recommended dose ranges from 25 mg to 100 mg, taken by mouth daily. It may be taken as a single dose or divided throughout the day, based on your provider’s recommendation.
Always follow your healthcare provider’s instructions for exact dosing.
FDA-approved uses
Hydrochlorothiazide is FDA-approved for:
- High Blood Pressure (Hypertension)
- Peripheral Edema (Swelling in the Ankles, Legs, Hands, and Feet) Caused by Heart Failure, Liver Cirrhosis, Nephrotic Syndrome and Medications Like Corticosteroids or Estrogen Therapy
common off-label uses
You may see hydrochlorothiazide prescribed for uses that are not “FDA-approved.” This is a very common and legal practice called “off-label” prescribing, where a doctor uses their clinical judgment to prescribe a drug for a different (but well-researched) purpose.
While primarily used for blood pressure and edema, healthcare providers may prescribe hydrochlorothiazide off-label for other medical conditions such as a kidney condition called nephrogenic diabetes insipidus and for preventing kidney stones.
side effects
Like all medications, Hydrochlorothiazide can cause side effects. Common side effects may improve as your body adjusts to the medication, but others may be serious and require medical attention.
Common Side Effects
- Increased urination
- Dizziness or lightheadedness
- Headache
- Weakness
- Blurry vision
- Low blood pressure
- Changes in electrolyte levels
Serious Side Effects
Serious side effects are rare, but it’s important to know what to look for if they do occur. Stop using hydrochlorothiazide and call your doctor immediately if you experience:
- Severe Allergic Reactions – Symptoms include swelling of the face, lips, tongue, or throat; difficulty breathing or swallowing; severe rash or itching; fever.
- Changing Electrolyte Levels – Hydrochlorothiazide may affect levels of minerals such as sodium, potassium, magnesium, calcium, and chloride. Symptoms include weakness, muscle cramps, constipation, nausea, vomiting, confusion, difficulty breathing, fainting, seizure, or irregular heartbeats.
- Increased Blood Sugar Levels (Hyperglycemia) – Hydrochlorothiazide can also increase blood glucose levels, leading to symptoms such as increased thirst or hunger, headache, blurred vision, and fatigue.
- Low Blood Pressure and Worsening Kidney Function – Fluid loss from hydrochlorothiazide can lead to dehydration and dangerously low blood pressure. Signs include feeling faint or dizzy when standing up, decreased need to urinate, dark or strong-smelling urine, weakness or fatigue, dry mouth, and headache.
- Eye Problems – Hydrochlorothiazide may cause vision-related side effects such as short-sightedness or narrow-angle glaucoma. Symptoms include difficulty seeing faraway objects, vision loss, eye pain or redness, seeing colorful halos around lights, and severe headache or vomiting.
- Severe Skin Reactions – In rare cases, life-threatening skin reactions like Stevens-Johnson Syndrome (SJS) or Toxic Epidermal Necrolysis (TEN) can occur when taking hydrochlorothiazide. Symptoms include painful red or purple skin that peels, red rash or blisters, and red, painful, or watery eyes.
- Pancreatitis – Inflammation of the pancreas may present as severe upper stomach pain radiating to the back, accompanied by vomiting and fever.
- Liver Damage – Signs include yellowing of the skin or eyes (jaundice), dark urine, light-colored stool, and severe abdominal pain.
Call your doctor immediately if you experience any concerning or prolonged symptoms.
pharmacist tips
- Take It in the Morning – As a diuretic, hydrochlorothiazide will make you urinate more often. To avoid waking up in the middle of the night to use the restroom, it is recommended to take your dose in the morning, with or without food. If it causes an upset stomach, try taking it with food.
- Stay Hydrated (with Caution) – Ask your prescriber how much water you should drink on hydrochlorothiazide. While you need to prevent dehydration, drinking excessive amounts of water can be dangerous for people with heart failure or liver issues.
- Use Sun Protection – This drug can cause photosensitivity, making your skin more sensitive to sunlight and tanning beds. Always wear sunscreen, hats, and protective clothing when outdoors to lower the risk of sunburn and skin cancer.
- Stand Up Slowly – You may feel dizzy when taking this medication due to its blood-pressure-lowering effects. Transition slowly from sitting or lying down to standing to avoid falls or feeling unsteady.
- Limit Alcohol – Alcohol can increase the diuretic effect of hydrochlorothiazide, raising the risk of dehydration and dizziness. It is recommended to limit or avoid alcohol intake while on this medication.
- Monitor Blood Sugar – If you have diabetes, be aware that hydrochlorothiazide can affect blood sugar levels. Monitor your glucose closely and report any changes to your care team, as your diabetes medication dosage may need to be adjusted.
- Keep Up With Bloodwork – Your healthcare provider may recommend regular blood testing to ensure the medication is not affecting your electrolyte levels.
- Missed Doses – If a dose is missed, take it as soon as you remember, unless it’s almost time for your next dose. In that case, skip the missed dose and take your next dose as usual. Do not double up on doses of hydrochlorothiazide.
drug interactions
Hydrochlorothiazide can interact with other medications, potentially altering their effectiveness or increasing the risk of side effects. For example:
- NSAIDs Pain Relievers – Nonsteroidal anti-inflammatory drugs like ibuprofen (Advil) or naproxen (Aleve) may reduce the effectiveness of hydrochlorothiazide.
- Lithium – Hydrochlorothiazide may interact with lithium, a medication used for depression.
- Digoxin – Hydrochlorothiazide may interfere with digoxin, a heart failure medication.
- Cholesterol Medications – Drugs like cholestyramine and colestipol can interfere with the absorption of hydrochlorothiazide.
- Diabetes Medications – Because water pills can raise blood sugar, your diabetes medications (like insulin or oral drugs) may require adjustment.
- Blood Pressure Medications – Taking other blood pressure medications with hydrochlorothiazide may cause blood pressure to drop too low.
- Diuretics – Combining hydrochlorothiazide with other “water pills” can increase dehydration risks.
- Opioids and Barbiturates – Medications such as morphine, codeine, or phenobarbital may interact with hydrochlorothiazide.
- Corticosteroids – Drugs like prednisone can worsen electrolyte depletion when combined with diuretics.
Always give your doctor and pharmacist a complete list of all your medications, vitamins, and supplements to check for potential interactions.
FAQs
Why should I take hydrochlorothiazide in the morning instead of at night?
It is recommended to take hydrochlorothiazide in the morning because it is a diuretic that increases urination. Taking it in the evening increases the likelihood that you will have to wake up in the middle of the night to use the bathroom, disrupting your sleep.
Does hydrochlorothiazide deplete potassium levels?
Yes, it can. Hydrochlorothiazide works by removing excess water and electrolytes through urine, which can lead to the body losing too much potassium. Your provider may monitor your levels and recommend potassium-rich foods or supplements if levels drop too low.
Can I drink alcohol while taking hydrochlorothiazide?
It is recommended to limit or avoid alcohol while taking hydrochlorothiazide. Both alcohol and hydrochlorothiazide promote fluid loss, which can significantly increase the risk of dehydration. Additionally, alcohol can increase dizziness, a possible side effect of the medication.
Why does hydrochlorothiazide cause sun sensitivity?
Hydrochlorothiazide causes photosensitivity, meaning your skin reacts more intensely to light from the sun, sunlamps, and tanning beds. This increases the risk of sunburn and skin cancer, so protective clothing and sunscreen are strongly recommended.
Can hydrochlorothiazide trigger gout attacks?
Yes. Hydrochlorothiazide can raise uric acid levels in the body. In people with a history of gout, this can cause or worsen gout attacks, leading to swollen, red, or painful joints.
Can hydrochlorothiazide cause erectile dysfunction?
Yes, some men experience difficulty getting or maintaining an erection while taking this medication. If this affects your sex life, speak to your prescriber, as they may adjust your dose or have you switch to another medication.
How long does it take for hydrochlorothiazide to lower blood pressure?
While the diuretic effect of hydrochlorothiazide starts within about 2 hours, the impact on blood pressure takes longer — anywhere from a few days to weeks.
Can I take ibuprofen (Advil) or naproxen (Aleve) with hydrochlorothiazide?
You should use caution. NSAIDs like ibuprofen and naproxen can sometimes make hydrochlorothiazide work less effectively. They can also increase the risk of kidney issues. It is recommended to talk to your healthcare provider before taking ibuprofen or naproxen with hydrochlorothiazide.
Is hydrochlorothiazide safer than lisinopril?
Hydrochlorothiazide and lisinopril are both common blood pressure medications but they work differently. They are sometimes prescribed together because using multiple medications is common for blood pressure management. Your doctor will determine whether hydrochlorothiazide vs. lisinopril is safest for you based on your kidney function and electrolyte levels.
Why do I have muscle cramps while taking hydrochlorothiazide?
Muscle cramps can be a sign that your electrolyte levels have dropped too low. Because hydrochlorothiazide removes potassium, magnesium, and sodium from the body, cramps or twitching may occur if these levels become unbalanced. Contact your healthcare provider if you experience muscle cramps on hydrochlorothiazide.
compare medications
Compared: Hydrochlorothiazide, Spironolactone (Aldactone), Furosemide (Lasix), Torsemide, Lisinopril-HCTZ, or Losartan-HCTZ?
There are several medications that your doctor can prescribe in place of hydrochlorothiazide. Here are a few possible alternatives below.
- Spironolactone (Aldactone) – A diuretic that is prescribed for high blood pressure and heart failure. In contrast to hydrochlorothiazide, spironolactone is a “potassium-sparing” diuretic, meaning it helps the body get rid of water while retaining potassium.
- Furosemide (Lasix) – A diuretic that is used to treat high blood pressure and swelling (edema) related to heart failure and liver or kidney problems.
- Torsemide – Another diuretic that is prescribed for high blood pressure and swelling (edema) related to heart failure and kidney or liver problems.
- Lisinopril-HCTZ – A combination ACE inhibitor and diuretic that may be prescribed when a single medication does not adequately lower blood pressure.
- Losartan-HCTZ – A combination angiotensin receptor blocker (ARB) and diuretic that may be prescribed when a single medication does not adequately lower blood pressure.
Disclaimer
Important: Information on this page is for educational purposes only. Prescribing decisions are made by independent, licensed providers. TelyRx operates technology-enabled pharmacies and a telehealth platform that connects patients with board-certified licensed providers. Prescriptions, when provider-approved and issued, are filled and shipped by TelyRx-affiliated pharmacies. We do not employ physicians or make prescribing decisions. Learn more about our editorial standards here.