Hydrochlorothiazide Tablets

Hydrochlorothiazide is a well-established thiazide diuretic supplied as oral tablets in 12.5 mg and 25 mg strengths. We offer a range of pack sizes for customers using it for blood pressure control or fluid retention, including those who require ongoing treatment.

What Hydrochlorothiazide tablets do

Hydrochlorothiazide reduces sodium and water reabsorption in the kidneys, increasing urine output and reducing excess fluid. Prescribers use it for hypertension and for oedema associated with heart, liver or kidney conditions, often alongside another medicine such as Lisinopril when one medicine is not enough to reach target blood pressure. Customers comparing blood pressure options can also browse our Blood Pressure range for related treatments.

Essential facts

Dosing and administration

For hypertension, adults commonly start on 12.5 mg to 25 mg once daily, usually taken in the morning to reduce night-time trips to the toilet. A prescriber may adjust the dose within the usual treatment range according to blood pressure response; doses above 25 mg often increase the risk of electrolyte disturbance without providing much additional blood pressure benefit. Dosing for oedema may differ and must follow the prescriber's directions. Hydrochlorothiazide tablets can be taken with or without food, although taking them with a light meal may reduce stomach upset. In children, dosing is calculated by body weight, generally around 1-2 mg/kg/day, with lower ceilings for infants and close medical supervision.

Onset, duration and monitoring

Diuresis typically begins within about two hours, reaches its peak after approximately four hours and lasts for roughly six to twelve hours. Its blood pressure-lowering effect supports the once-daily regimen commonly used for hypertension. Because hydrochlorothiazide affects fluid and electrolyte balance, prescribers often check sodium, potassium, blood glucose, uric acid and kidney function, particularly after treatment starts or the dose changes.

Common side effects and interactions

• Increased urination, mild dizziness or lightheadedness, especially when standing up quickly
• Low potassium, sodium or magnesium levels, particularly with ongoing use
• Raised blood sugar or uric acid, which matters for people with diabetes or gout
• Interactions with other blood pressure medicines, lithium, NSAIDs and some diabetes medicines

Hydrochlorothiazide should not be used by people with anuria or a known hypersensitivity to hydrochlorothiazide or relevant sulfonamide-derived medicines. A prescriber should review other medicines and existing kidney, liver, electrolyte, diabetes or gout concerns before treatment.

Available strengths and pack sizes

Although hydrochlorothiazide is a Schedule 4 prescription-only medicine in Australia and requires prescribing by an authorised prescriber, our ordering policy does not require you to send us a prescription before we accept your order. Our pharmacist team is available 24/7 by email, online chat or phone if you have questions about ordering the available strengths or pack sizes.

We supply hydrochlorothiazide as tablets counted per pack. The 12.5 mg strength is available in packs of 30, 60, 90, 120, 180 or 360 tablets, while the 25 mg strength is available in packs of 90, 120, 180, 270 or 360 tablets.

Important safety notes

• Allergies: hydrochlorothiazide is a sulfonamide-derived medicine, so a history of sulfonamide allergy should be discussed with a prescriber before starting.
• Pregnancy and breastfeeding: thiazide diuretics are generally avoided during pregnancy and while breastfeeding because they can reduce placental perfusion and may suppress lactation.
• Diabetes: hydrochlorothiazide can raise blood glucose, so people with diabetes may need closer monitoring or a dose review for their other medicines.
• Driving: dizziness can occur, particularly when treatment starts or the dose changes, so care is needed before driving or using machinery.

Hydrochlorothiazide may be listed on the Pharmaceutical Benefits Scheme for eligible uses, although availability and conditions depend on the specific product, strength and listing. Registration of the exact tablet product, strength and sponsor has not been confirmed, so check the TGA Australian Register of Therapeutic Goods for the specific medicine. Suspected adverse effects can be reported to the Therapeutic Goods Administration through its medicine safety reporting system. We store our stock at room temperature between 20°C and 25°C, protected from light and moisture, and pack every order discreetly for delivery across Australia.