Generic
Metolazone
3 brands available in the market
At a glance
Metolazone is a thiazide-like diuretic used to treat hypertension and edema (fluid overload) associated with heart, liver, kidney, or lung disease.
Description
Metolazone is a quinazoline diuretic with properties similar to thiazide diuretics. It inhibits sodium reabsorption in the distal tubule and to a lesser extent in the proximal convoluted tubule, increasing excretion of sodium and water. It lowers blood pressure and removes excess fluid from the body. Over time it also relaxes blood vessels and improves blood flow.
Indications
- Hypertension (high blood pressure)
- Edema (fluid overload) associated with heart failure, liver, kidney, or lung disease
- Edema associated with nephrotic syndrome
- Edema associated with renal disease
Therapeutic class
Thiazide and Related Diuretics
Pharmacological class
Thiazide-like Diuretic
Pharmacology
Metolazone is a quinazoline diuretic with properties generally similar to thiazide diuretics. It 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. It does not inhibit carbonic anhydrase.
Mechanism of action
Lowers blood pressure and reduces edema by increasing excretion of sodium and water.
Dosage
Adult Dose (Oral):
- Hypertension: Initial: 1.25 mg daily; adjusted after 3-4 weeks; Maintenance: 2.5-5 mg daily
- Edema (Heart Failure): 5-10 mg daily; increased if necessary to 20 mg daily; Max: 80 mg in 24 hr
- Edema (Renal Disease): 5-20 mg daily
- Elderly: Initial: 2.5 mg/day or every other day
Child Dose: 0.2-0.4 mg/kg/day (single daily dose or divided q12hr)
Administration
- Take with food (to avoid upset stomach)
- Swallow tablet whole; do not chew, crush or break
- Take in the morning (to avoid nighttime urination)
- Take at the same time each day
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Headache
- Nausea
- Increased blood uric acid
- Decreased potassium level in blood
- Glucose intolerance
- Altered blood lipid level
- Dizziness
Serious Side Effects:
- Hyponatremia (sudden drop of sodium level)
- Hypokalemia (potassium loss)
- Hyperuricemia
- Orthostatic hypotension
- Pancreatitis
- Hepatitis
Precautions & warnings
- Caution while driving (may cause dizziness, blurred vision)
- Take in the morning with breakfast (to avoid nighttime urination)
- Avoid alcohol (may increase dizziness)
- Monitor kidney function and electrolytes regularly
- Monitor blood pressure regularly
- Caution in diabetes, gout, SLE
- Caution in hepatic and renal impairment
Contraindications
- Anuria (no urine production)
- Hepatic coma or pre-coma
- Pregnancy
- Hypersensitivity to Metolazone or components
Drug interactions
- ACE Inhibitors: Enhanced hypotensive and nephrotoxic effects
- Bile Acid Sequestrants: Reduced absorption
- Diazoxide: Enhanced hyperglycemic effect
- Dofetilide: Increased serum concentration and QTc effect
- Lithium: Reduced excretion
- Alcohol: Increased hypotensive effect
- Cyclosporine: Risk of nephrotoxicity (potentially fatal)
- Furosemide: Severe electrolyte disturbances
Food interactions
Alcohol with Metolazone may increase dizziness.
Use in pregnancy
Use in Pregnancy: Generally considered safe. Animal studies show low or no adverse effects on developing baby; limited human studies.
Pregnancy Category: B — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Probably safe. Limited human data suggests the drug does not represent significant risk to the baby.
Pediatric use
Safety and efficacy in children have not been established; not recommended.
Geriatric use
Elderly: Initial dose 2.5 mg/day or every other day.
Renal / hepatic impairment
Renal Impairment: Safe - no dose adjustment required. No need to supplement dose in hemodialysis or peritoneal dialysis.
Hepatic Impairment: Limited information available. Consult your doctor.
Overdose effects
Overdose may cause excessive diuresis, electrolyte disturbances, hypotension. Symptomatic treatment.
Storage conditions
Keep below 30°C temperature, away from light & moisture. Keep out of reach of children.
Chemical structure
Metolazone