Hydrochlorothiazide is a thiazide diuretic and antihypertensive medication used primarily in the management of high blood pressure (hypertension) and certain conditions associated with excess fluid retention or edema. It acts within the kidneys to increase the excretion of sodium and water, reducing circulating fluid volume and helping lower blood pressure.
Hydrochlorothiazide acts primarily on the distal renal tubules, where it reduces the reabsorption of sodium and chloride. Increased urinary sodium excretion draws additional water into the urine, producing its characteristic diuretic effect. Some potassium and bicarbonate may also be lost during this process, which is why electrolyte monitoring can be important during ongoing treatment.
Following oral administration, the diuretic effect generally begins within approximately 2 hours, reaches its maximum effect at around 4 hours, and may continue for approximately 6 to 12 hours. Hydrochlorothiazide is not extensively metabolized and is eliminated primarily through the kidneys.
For hypertension, hydrochlorothiazide may be used alone or alongside other antihypertensive medications. It can also be prescribed as adjunctive treatment for edema associated with conditions such as congestive heart failure, liver cirrhosis, certain kidney disorders, and some medication related causes of fluid retention.
This product provides:
- Active Ingredient: Hydrochlorothiazide
- Strength: 25mg per tablet
- Quantity: 100 Tablets
- Drug Class: Thiazide Diuretic
- Dosage Form: Oral Tablet
- Common Uses: Hypertension and Edema
Hydrochlorothiazide 25mg is a prescription medication in Canada, with multiple 25mg formulations currently listed as marketed products by Health Canada.
Because hydrochlorothiazide increases fluid and electrolyte excretion, treatment can produce low potassium, low sodium, dehydration, dizziness, and low blood pressure in susceptible patients. Electrolyte levels and kidney function may therefore require monitoring, particularly during prolonged treatment or when hydrochlorothiazide is combined with other medications that affect blood pressure or electrolytes.
Thiazide diuretics can also increase uric acid and blood glucose levels, potentially worsening gout or affecting glucose control in susceptible individuals. Hydrochlorothiazide should be used cautiously in patients with significant kidney or liver impairment.
A rare but important adverse reaction associated with hydrochlorothiazide is acute angle closure glaucoma, which can present with sudden eye pain or reduced vision and requires urgent medical assessment. Long term cumulative hydrochlorothiazide exposure has also been associated with an increased risk of certain non melanoma skin cancers, making sensible sun protection particularly important during prolonged therapy.
Hydrochlorothiazide should be used according to the directions of a qualified healthcare professional, with the dose and monitoring requirements individualized according to blood pressure response, fluid balance, kidney function, and other medications.
