Hydrochlorothiazide (HCTZ) is a prescription medication used to treat high blood pressure and fluid retention. Hydrochlorothiazide belongs to a group of drugs called diuretics ("water pills"), which help the body get rid of excess fluid.
This medication comes in tablet and capsule forms. Hydrochlorothiazide is usually taken once in the morning, with or without food.
Common side effects of hydrochlorothiazide include frequent urination, weakness, and dizziness. Do not drive or operate machinery until you know how hydrochlorothiazide will affect you.
Hydrochlorothiazide is a prescription medication that is used alone or together with other medicines to treat high blood pressure (hypertension). It is also used to treat fluid retention (edema) caused by certain medications, congestive heart failure, severe liver disease, and kidney disease.
This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.
Frequent urination (having to pee often), one of the side effects of hydrochlorothiazide, should go away after you've been taking it for a few weeks. Tell your doctor if any of these symptoms are severe or do not go away:
- muscle weakness
- stomach pain
- loss of appetite
- hair loss
- sexual dysfunction (impotence)
If you experience any of the following symptoms, call your doctor immediately:
- sore throat with fever
- unusual bleeding or bruising
- severe skin rash with peeling skin
- difficulty breathing or swallowing
Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:
- other medicines for high blood pressure
- NSAIDs (such as ibuprofen, naproxen, others)
- corticosteroids (such as prednisone, hydrocortisone, others)
- lithium (Eskalith, Lithobid)
- oral (taken by mouth) medications for diabetes
- narcotics such as hydrocodone, codeine, morphine, oxycodone
- barbiturates such as amobarbital (Amytal), butabarbital (Butisol Sodium), phenobarbital (Luminal), primidone (Mysoline), pentobarbital (Nembutal), thiopental (Pentothal)
- probenecid (Benemid)
- cholestyramine (Prevalite, Questran)
- colestipol (Colestid)
This is not a complete list of hydrochlorothiazide drug interactions. Ask your doctor or pharmacist for more information.
Before receiving this medication, tell your doctor if you are allergic to hydrochlorothiazide, sulfa drugs, or any other medication.
This medication may decrease your potassium levels. Symptoms of low potassium levels include:
- Abnormal heart rhythms, especially in people with heart disease
- Muscle damage
- Muscle weakness or spasms
- Paralysis (which can include the lungs)
Hydrochlorothiazide can cause dizziness. Do not drive or operate heavy machinery until you know how hydrochlorothiazide affects you. Limit alcoholic beverages.
If you have diabetes, this medication may affect your glucose levels.
This medication may cause a decrease in kidney function, especially in certain groups (such as those with severe congestive heart failure). Tell your doctor if you have the following symptoms:
- decrease in urine output (producing less pee),
- back pain
Tell your doctor if you have prolonged diarrhea or vomiting as this may lead to a serious loss of body water (dehydration) To prevent dehydration, drink plenty of fluids unless your doctor directs you otherwise.
Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of hydrochlorothiazide there are no specific foods that you must exclude from your diet when receiving hydrochlorothiazide.
Before receiving this medication, tell your doctor if you have:
- liver disease
- kidney disease
Tell your doctor about all the medications you take including prescription and non-prescription medicines, vitamins, and herbal supplements.
Tell your doctor if you are pregnant or breastfeeding.
If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking hydrochlorothiazide.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if hydrochlorothiazide will harm your unborn baby. Research studies in animals have not shown evidence of harm to the fetus, however, there are no adequate studies in pregnant women.
Tell your doctor if you are breastfeeding or plan to breastfeed. Hydrochlorothiazide is excreted in human breast milk. There is some evidence it may reduce the amount of breast milk produced by women who take it. Because of the possibility for serious adverse effects in nursing infants, you and your doctor will need to decide if you should stop breastfeeding or stop taking hydrochlorothiazide.
Hydrochlorothiazide comes as a tablet and a capsule. It is usually taken once a day, although it is sometimes taken two or three times a day. Because hydrochlorothiazide increases urination, it is best taken in the morning to avoid having to get up in the night to urinate. If you take it more than once a day, take your last dose by late afternoon. This medication can be taken with or without food. If necessary, hydrochlorothiazide tablets may be split.
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose.
Take hydrochlorothiazide exactly as prescribed. Follow the directions on your prescription label carefully. Your doctor will determine the best dose for you.
For adults with fluid retention (edema) the usual dosage is 25 mg to 100 mg daily. The dose can be split into two smaller daily doses. For some people, hydrochlorothiazide works well if taken on alternate days or on three to five days each week. For infants and children with fluid retention, the dose must be calculated using body weight.
For adults with high blood pressure the usual starting dose is 25 mg daily. The dose may be increased to 50 mg daily, to be taken as a single dose or split into two daily doses. Most people do not need more than 50 mg of hydrochlorothiazide daily if it is taken along with another blood pressure medication. For infants and children with high blood pressure, the dose must be calculated using body weight.
If you take too much hydrochlorothiazide, call your local Poison Control Center or seek emergency medical attention right away.
Hydrochlorothiazide tablets are available in 12.5 mg, 25 mg, and 50 mg strengths.
Hydrochlorothiazide capsules are available in a 12.5 mg form.
Store hydrochlorothiazide tablets and capsules at room temperature away from excess light and moisture. Keep this and all medications out of the reach of children.