Drug Groups

approved

Description

A quinazoline-sulfonamide that is considered a thiazide-like diuretic which is long-acting so useful in chronic renal failure. It also tends to lower blood pressure and increase potassium loss. [PubChem]

Indication

For the treatment of hypertension, alone or in combination with other antihypertensive drugs of a different class.

Pharmacology

Metolazone is a quinazoline diuretic, with properties generally similar to the thiazide diuretics. A proximal action of metolazone has been shown in humans by increased excretion of phosphate and magnesium ions and by a markedly increased fractional excretion of sodium in patients with severely compromised glomerular filtration. This action has been demonstrated in animals by micropuncture studies.

Toxicity

Symptoms of overdose include difficulty breathing, dizziness, dizziness on standing up, drowsiness, fainting, irritation of the stomach and intestines, and lethargy leading to coma.

Affected Organisms

Biotransformation

Not substantially metabolized. 70-95% is excreted unchanged in urine via glomerular filtration and active tubular secretion. Undergoes enterohepatic recycling.

Absorption

Peak blood levels are obtained within 2 to 4 hours of oral administration. The rate and extent of absorption are formulation dependent.

Half Life

Approximately 14 hours.

Protein Binding

50-70% bound to erythrocytes, up to 33% bound to plasma proteins, 2-5% of the drug in circulation is unbound

Elimination

Most of the drug is excreted in the unconverted form in the urine.

References

External Links