Hydrochlorothiazide: Price, Dosage & Where to Buy

Hydrochlorothiazide is a thiazide diuretic, a type of medicine that helps the kidneys remove salt and water, and is mainly prescribed to manage high blood pressure. It may be used on its own or alongside other blood pressure medicines, depending on the treatment plan. Hydrochlorothiazide is available as a generic medicine and requires a prescription in the United Kingdom.

Hydrochlorothiazide belongs to the thiazide group of diuretics, sometimes called water tablets. These medicines act in the kidneys, reducing the amount of salt that is returned to the bloodstream. More salt leaves the body in urine, and water follows it.

This reduces the amount of fluid circulating in the blood, helping to lower blood pressure. With continued treatment, thiazides also help reduce resistance in the blood vessels. Their effects on salt and water balance can also affect blood electrolyte levels.

Hydrochlorothiazide capsules are indicated for managing hypertension, commonly called high blood pressure. The medicine can be used alone or together with other medicines that lower blood pressure. The label also describes limited use of diuretics for swelling during pregnancy when the swelling has a medical cause.

Routine use in an otherwise healthy pregnant woman is not appropriate, and diuretics do not prevent pregnancy-related toxaemia. Swelling caused by the normal physical changes of pregnancy generally does not call for a diuretic, although the label describes rare circumstances where severe discomfort may justify a short course.

The label lists oral capsules and gelatin-coated oral capsules containing 12.5 mg. The label lists oral tablets containing 12.5 mg, 25 mg and 50 mg, and powder for oral suspension at 10 mg/mL. The usual starting dose is one capsule once daily for adults with hypertension, whether used alone or with other antihypertensive medicines.

The label lists total daily doses greater than 50 mg as not recommended. The capsule dosing information relates to control of high blood pressure; it does not set out separate dosing schedules for every available form. The label describes adverse reactions as dose-related and states that moderate or severe reactions may require a reduction in dosage or withdrawal of treatment.

These are label facts rather than an individual treatment plan. The appropriate formulation and treatment plan depend on the prescriber's assessment, including kidney function, other medicines and the response to treatment.

Store at 20° to 25°C in a tight, light-resistant container. Protect from light, moisture and freezing, and keep the container tightly closed to maintain quality. Keep the medicine out of the reach of children.

A missed dose can interrupt the regular effect of a blood pressure medicine. General pharmacy advice is to resume the usual schedule rather than double a dose to make up for one missed. Check the patient leaflet or ask a pharmacist if the timing is unclear or doses are frequently missed.

Animal studies found no evidence of fetal harm, but there are no adequate, well-controlled studies in pregnant women. The label states that hydrochlorothiazide should be used during pregnancy only if clearly needed. Thiazides cross the placenta, with risks including fetal or newborn jaundice and thrombocytopenia, a low platelet count.

They also pass into breast milk. Because serious adverse reactions could occur in a breastfed infant, a decision about stopping breastfeeding or stopping hydrochlorothiazide should consider the medicine's importance to the mother.