| Item |
Information |
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Drug Groups
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approved |
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Description
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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 |
| • |
Humans and other mammals |
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| 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 |
| • |
Rosenberg J, Gustafsson F, Galatius S, Hildebrandt PR: Combination therapy with metolazone and loop diuretics in outpatients with refractory heart failure: an observational study and review of the literature. Cardiovasc Drugs Ther. 2005 Aug;19(4):301-6.
[Pubmed]
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