Nurses Compass
Drug Guide
Metolazone
Classification
Therapeutic: Diuretic, Antihypertensive
Pharmacological: Thiazide-like diuretic
FDA Approved Indications
- Edema associated with congestive heart failure, hepatic cirrhosis, or renal disease
- Hypertension
Mechanism of Action
Metolazone inhibits sodium reabsorption primarily in the distal convoluted tubule of the nephron, leading to increased excretion of sodium, chloride, and water, thereby reducing blood volume and blood pressure.
Dosage and Administration
Adult: Initially, 5 mg once daily. Dose may be increased to 10–20 mg daily based on response.
Pediatric: Not generally recommended for children due to lack of sufficient data.
Geriatric: Start at lower doses due to increased sensitivity; monitor renal function and electrolytes closely.
Renal Impairment: Adjust dose based on renal function; efficacy may be diminished in severe impairment.
Hepatic Impairment: Use with caution; no specific dosing adjustments established.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed; volume of distribution not well established.
Metabolism: Minimal hepatic metabolism.
Excretion: Primarily renal excretion.
Half Life: Approximately 24 hours.
Contraindications
- Allergy to sulfonamides or thiazides.
- Anuria.
- Electrolyte imbalances such as hyponatremia, hypokalemia.
Precautions
- Monitor renal function, electrolytes, and blood pressure regularly.
- Use with caution in patients with gout, systemic lupus erythematosus, or diabetes.
Adverse Reactions - Common
- Electrolyte disturbances (hyponatremia, hypokalemia) (Common)
- Dehydration (Common)
- Dizziness or lightheadedness (Common)
Adverse Reactions - Serious
- Electrolyte imbalance leading to arrhythmias (Serious)
- Hypersensitivity reactions (Rare)
- Blood dyscrasias (Rare)
Drug-Drug Interactions
- Other antihypertensives, NSAIDs, lithium, digitalis, corticosteroids
Drug-Food Interactions
- Alcohol may enhance hypotensive effects
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure, serum electrolytes, renal function, and for signs of dehydration.
Diagnoses:
- Risk for electrolyte imbalance
- Ineffective tissue perfusion related to hypotension
Implementation: Administer in the morning to reduce sleep disturbances; ensure adequate fluid and electrolyte intake.
Evaluation: Assess blood pressure and electrolytes regularly; evaluate for signs of dehydration or electrolyte imbalance.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report signs of electrolyte imbalance like muscle weakness, cramps, irregular heartbeat.
- Avoid excessive salt substitutes containing potassium unless prescribed.
- Follow-up blood tests to monitor electrolytes and renal function.
Special Considerations
Black Box Warnings:
- Electrolyte disturbances may lead to arrhythmias.
- Use with caution in patients with gout as it may precipitate attacks.
Genetic Factors: No specific genetic testing required.
Lab Test Interference: May alter serum electrolytes, blood glucose, or uric acid levels.
Overdose Management
Signs/Symptoms: Severe electrolyte imbalance, dehydration, hypotension.
Treatment: Discontinue medication, provide supportive care, correct electrolyte imbalances, and maintain hydration.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable when stored properly.