Oldren - General Information

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]


Pharmacology of Oldren

Oldren 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.


Oldren for patients

Patients should be informed of possible adverse effects, advised to take the medication as directed and promptly report any possible adverse reactions to the treating physician.


Oldren Interactions

Diuretics: Furosemide and probably other loop diuretics given concomitantly with metolazone can cause unusually large or prolonged losses of fluid and electrolytes.

Other Antihypertensives: When MYKROX Tablets are used with other antihypertensive drugs, care must be taken, especially during initial therapy. Dosage adjustments of other antihypertensives may be necessary.

Alcohol, Barbiturates, and Narcotics: The hypotensive effects of these drugs may be potentiated by the volume contraction that may be associated with metolazone therapy.

Digitalis Glycosides: Diuretic-induced hypokalemia can increase the sensitivity of the myocardium to digitalis. Serious arrhythmias can result.

Corticosteroids or ACTH: May increase the risk of hypokalemia and increase salt and water retention.

Lithium: Serum lithium levels may increase.

Curariform Drugs: Diuretic-induced hypokalemia may enhance neuromuscular blocking effects of curariform drugs (such as tubocurarine) the most serious effect would be respiratory depression which could proceed to apnea. Accordingly, it may be advisable to discontinue MYKROX Tablets three days before elective surgery.

Salicylates and Other Non-Steroidal Anti-Inflammatory Drugs: May decrease the antihypertensive effects of MYKROX Tablets.

Sympathomimetics: Metolazone may decrease arterial responsiveness to norepinephrine, but this diminution is not sufficient to preclude effectiveness of the pressor agent for therapeutic use.

Methenamine: Efficacy may be decreased due to urinary alkalizing effect of metolazone.

Anticoagulants: Metolazone, as well as other thiazide-like diuretics, may affect the hypoprothrombinemic response to anticoagulants; dosage adjustments may be necessary.


Oldren Contraindications

Anuria, hepatic coma or precoma, known allergy or hypersensitivity to metolazone.


Additional information about Oldren

Oldren Indication: For the treatment of hypertension, alone or in combination with other antihypertensive drugs of a different class.
Mechanism Of Action: The actions of metolazone result from interference with the renal tubular mechanism of electrolyte reabsorption. Oldren acts primarily to inhibit sodium reabsorption at the cortical diluting site and to a lesser extent in the proximal convoluted tubule. Sodium and chloride ions are excreted in approximately equivalent amounts. The increased delivery of sodium to the distal tubular exchange site results in increased potassium excretion. Oldren does not inhibit carbonic anhydrase. The antihypertensive mechanism of action of metolazone is not fully understood but is presumed to be related to its saluretic and diuretic properties.
Drug Interactions: Amantadine The diuretic increases the adverse effects of amantadine
Deslanoside Possible electrolyte variations and arrhythmias
Digitoxin Possible electrolyte variations and arrhythmias
Digoxin Possible electrolyte variations and arrhythmias
Dofetilide Increased risk of cardiotoxicity and arrhythmias
Lithium The thiazide diuretic increases serum levels of lithium
Food Interactions: Not Available
Generic Name: Metolazone
Synonyms: Metolazona [INN-Spanish]; Metolazonum [INN-Latin]
Drug Category: Antihypertensive Agents; Diuretics, Sulfamyl
Drug Type: Small Molecule; Approved

Other Brand Names containing Metolazone: Diulo; Metalazone; Metalozone; Metenix; Microx; Mykrox; Oldren; Xuret; Zaroxolyn;
Absorption: Peak blood levels are obtained within 2 to 4 hours of oral administration.
Toxicity (Overdose): Symptoms of overdose include difficulty breathing, dizziness, dizziness on standing up, drowsiness, fainting, irritation of the stomach and intestines, and lethargy leading to coma.
Protein Binding: Dose dependent.
Biotransformation: Not Available
Half Life: Approximately 14 hours.
Dosage Forms of Oldren: Tablet Oral
Chemical IUPAC Name: 7-chloro-2-methyl-3-(2-methylphenyl)-4-oxo-1,2-dihydroquinazoline-6-sulfonamide
Chemical Formula: C16H16ClN3O3S
Metolazone on Wikipedia:
Organisms Affected: Humans and other mammals