Hydrochlorothiazide

Absorption

An oral dose of hydrochlorothiazide is 65-75% bioavailable, with a Tmax of 1-5 hours, and a Cmax of 70-490ng/mL following doses of 12.5-100mg. When taken with a meal, bioavailability is 10% lower, Cmax is 20% lower, and Tmax increases from 1.6 to 2.9 hours.

Toxicity

The oral LD50 of hydrochlorothiazide is >10g/kg in mice and rats.
Patients experiencing an overdose may present with hypokalemia, hypochloremia, and hyponatremia. Treat patients with symptomatic and supportive treatment including fluids and electrolytes. Vasopressors may be administered to treat hypotension and oxygen may be given for respiratory impairment.

The Uses of Hydrochlorothiazide

Labelled Hydrochlorothiazide (H714560). Hydrochlorothiazide is a carbonic anhydrase inhibitor as a diuretic.

Background

Hydrochlorothiazide is the most commonly prescribed thiazide diuretic. It is indicated to treat edema and hypertension. Hydrochlorothiazide use is common but declining in favour of angiotensin converting enzyme inhibitors. Many combination products are available containing hydrochlorothiazide and angiotensin converting enzyme inhibitors or angiotensin II receptor blockers.
Hydrochlorothiazide was granted FDA approval on 12 February 1959.

Indications

Hydrochlorothiazide is indicated alone or in combination for the management of edema associated with congestive heart failure, hepatic cirrhosis, nephrotic syndrome, acute glomerulonephritis, chronic renal failure, and corticosteroid and estrogen therapy. Hydrochlorothiazide is also indicated alone or in combination for the management of hypertension.

What are the applications of Application

Hydrochlorothiazide is a carbonic anhydrase inhibitor

Pharmacokinetics

Hydrochlorothiazide prevents the reabsorption of sodium and water from the distal convoluted tubule, allowing for the increased elimination of water in the urine. Hydrochlorothiazide has a wide therapeutic window as dosing is individualized and can range from 25-100mg. Hydrochlorothiazide should be used with caution in patients with reduced kidney or liver function.

Metabolism

Hydrochlorothiazide is not metabolized.