Drug Groups

approved

Description

A thiazide diuretic with properties similar to those of hydrochlorothiazide. (From Martindale, The Extra Pharmacopoeia, 30th ed, p830)

Indication

Used in the treatment of oedema (including that associated with heart failure) and hypertension.

Pharmacology

Trichloromethiazide is indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy. Trichloromethiazide has also been found useful in edema due to various forms of renal dysfunction such as nephrotic syndrome, acute glomer-ulonephritis, and chronic renal failure. Trichloromethiazide is also indicated in the management of hypertension either as the sole therapeutic agent or to enhance the effectiveness of other antihypertensive drugs in the more severe forms of hypertension. Like other thiazides, Trichloromethiazide promotes water loss from the body (diuretics). They inhibit Na⁺/Cl^- reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of potassium and an increase in serum uric acid. Thiazides are often used to treat hypertension, but their hypotensive effects are not necessarily due to their diuretic activity. Thiazides have been shown to prevent hypertension-related morbidity and mortality although the mechanism is not fully understood. Thiazides cause vasodilation by activating calcium-activated potassium channels (large conductance) in vascular smooth muscles and inhibiting various carbonic anhydrases in vascular tissue.

Toxicity

Oral Rat LD₅₀ = 5600 mg/kg, oral Mouse LD₅₀ = 2600 mg/kg

Affected Organisms