Drug Guide
Hydroflumethiazide
Classification
Therapeutic: Antihypertensive, Diuretic
Pharmacological: Thiazide diuretic
FDA Approved Indications
- Hypertension
- Edema related to congestive heart failure, hepatic cirrhosis, or renal disease
Mechanism of Action
Hydroflumethiazide 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: Typically 25-100 mg daily in divided doses or once daily; specific dosing depends on patient response and condition.
Pediatric: Use with caution; dosing determined by weight and age, usually starting with low doses and titrating upward as needed.
Geriatric: Start at lower doses due to increased sensitivity and risk of fluid/electrolyte imbalances.
Renal Impairment: Use with caution; dose adjustments may be necessary due to altered drug clearance.
Hepatic Impairment: Use with caution; monitor for fluid/electrolyte disturbances.
Pharmacokinetics
Absorption: Rapidly absorbed from the gastrointestinal tract.
Distribution: Widely distributed throughout body tissues and fluids.
Metabolism: Minimal hepatic metabolism.
Excretion: Primarily renal excretion of unchanged drug and metabolites.
Half Life: 12-15 hours, allowing for once-daily dosing.
Contraindications
- Anuria
- Hypersensitivity to sulfonamide-derived drugs
Precautions
- Electrolyte imbalances (e.g., hypokalemia, hyponatremia)
- History of gout or diabetes mellitus
- Monitor blood pressure, electrolytes, renal function regularly.
Adverse Reactions - Common
- Electrolyte imbalances (hypokalemia, hyponatremia) (Common)
- Dizziness or orthostatic hypotension (Common)
- Gastrointestinal disturbances (Common)
Adverse Reactions - Serious
- Electrolyte disturbances leading to arrhythmias (Serious)
- Hypersensitivity reactions, including rash or Stevens-Johnson syndrome (Serious)
- Blood dyscrasias (Rare)
Drug-Drug Interactions
- Other antihypertensives, especially ACE inhibitors and diuretics, increasing risk of hypotension and electrolyte disturbances
- Lithium (risk of toxicity)
Drug-Food Interactions
- Alcohol may enhance hypotensive effects.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure, electrolyte levels (potassium, sodium), renal function, and volume status regularly.
Diagnoses:
- Risk for electrolyte imbalance
- Altered fluid volume
- Risk for hypotension
Implementation: Administer as prescribed, monitor vital signs and laboratory values, educate patient on signs of electrolyte imbalance.
Evaluation: Assess for effective blood pressure control and absence of adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report symptoms of electrolyte imbalance (muscle weakness, cramps), dizziness, or unusual bleeding.
- Maintain adequate hydration.
- Limit alcohol intake.
Special Considerations
Black Box Warnings:
- Electrolyte disturbances can lead to serious cardiac arrhythmias.
Genetic Factors: None specific.
Lab Test Interference: May alter serum electrolyte tests and glucose levels.
Overdose Management
Signs/Symptoms: Severe electrolyte imbalances, dehydration, hypotension.
Treatment: Discontinue medication, administer IV fluids, electrolyte replacement as needed, and monitor cardiac status.
Storage and Handling
Storage: Store at room temperature, 20-25°C (68-77°F).
Stability: Stable under normal conditions, protect from moisture and light.