HYDROCHLOROTHIAZIDE

For information on Pharmacology, Uses, Indications, Contraindications-/Precautions,
Adverse Effects, Warnings, Overdosage, Drug Interactions, and Monitoring Parameters;see the Chlorothiazide monograph.
Chemistry - Hydrochlorothiazide occurs as a practically odorless, slightly bitter-tasting, white, orpractically white, crystalline powder with pKas of 7.9 and 9.2. It is slightly soluble in water andsoluble in alcohol.

Storage, Stability, Compatibility

Hydrochlorothiazide oral solution and tablets should bestored at room temperature in well-closed containers. Avoid freezing the oral solution and theinjectable product.

Pharmacokinetics - HYDROCHLOROTHIAZIDE

The pharmacokinetics of the thiazides have apparently not been studied indomestic animals. In humans, hydrochlorothiazide is about 65 to 75% absorbed after oral administration. The onset of diuretic activity occurs in 2 hours; peaks at 4 - 6 hours. The serum half-life is approximately 5.6 - 14.8 hours and the duration of activity is 6-12 hours. The drug is apparently not metabolized and is excreted unchanged into the urine. Like all thiazides, the antihypertensive effects of hydrochlorothiazide may take several days to occur.