Nurses Compass
Drug Guide
Chlorothiazide
Classification
Therapeutic: Antihypertensive; Diuretic
Pharmacological: Thiazide diuretic
FDA Approved Indications
- Hypertension
- Edema associated with congestive heart failure, cirrhosis of the liver, and corticosteroid and estrogen therapy
Mechanism of Action
Inhibits sodium reabsorption in the distal tubules of the kidney, leading to increased excretion of sodium, chloride, and water, thereby reducing blood volume and lowering blood pressure.
Dosage and Administration
Adult: Initial dose: 500 mg once daily or in two divided doses. Dose may be increased as needed, typically up to 2 g per day.
Pediatric: Not generally recommended for children due to lack of sufficient data.
Geriatric: Start at lower doses due to increased risk of hypotension and electrolyte imbalance; monitor closely.
Renal Impairment: Use with caution; may require dose adjustments and frequent monitoring.
Hepatic Impairment: Use with caution; avoid in severe impairment due to limited data.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed, including into the cerebrospinal fluid; highly protein-bound.
Metabolism: Primarily unchanged in the urine; minimal hepatic metabolism.
Excretion: Renal excretion, mainly unchanged.
Half Life: Approximate plasma half-life of 7-14 hours.
Contraindications
- Hypersensitivity to chlorothiazide or other sulfonamide-derived drugs
- Anuria
Precautions
- Electrolyte disturbances (hypokalemia, hyponatremia), gout, lupus erythematosus, diabetes mellitus, renal or hepatic impairment, elderly patients
Adverse Reactions - Common
- Electrolyte disturbances (hypokalemia, hyponatremia) (Common)
- Increased urination (Common)
- Hyperuricemia (Common)
Adverse Reactions - Serious
- Electrolyte imbalance leading to arrhythmias, hypotension, dehydration (Serious)
- Stevens-Johnson syndrome, toxic epidermal necrolysis (Rare)
Drug-Drug Interactions
- Digoxin (risk of hypokalemia increasing toxicity), corticosteroids (additive hypokalemia), other antihypertensives
Drug-Food Interactions
- Alcohol (may enhance hypotensive effect)
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure, serum electrolytes, renal function, hydration status.
Diagnoses:
- Deficient fluid volume r/t excessive diuresis
- Electrolyte imbalance, risk of hypokalemia
Implementation: Administer with meals to minimize gastrointestinal upset; monitor electrolyte levels regularly.
Evaluation: Assess blood pressure response, electrolyte levels, and signs of dehydration or electrolyte imbalance.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report symptoms of electrolyte imbalance (muscle weakness, cramps, irregular heartbeat).
- Limit alcohol intake, and avoid excessive salt or potassium supplements unless directed.
- Follow up for blood tests to monitor electrolytes and renal function.
Special Considerations
Black Box Warnings:
- Electrolyte imbalances can lead to serious cardiac arrhythmias.
Genetic Factors: None specifically documented.
Lab Test Interference: May cause false elevation of serum uric acid or glucose levels.
Overdose Management
Signs/Symptoms: Severe electrolyte imbalance, dehydration, hypotension, dizziness, weakness.
Treatment: Discontinue drug, correct electrolyte imbalances with IV fluids and electrolytes, monitor vital signs and renal function.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable under recommended storage conditions.