Generic Name

Benzthiazide

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Classification

FDA Approved Indications

• Treatment of hypertension
• Edema associated with congestive heart failure, hepatic cirrhosis, or renal disease

Mechanism of Action

Benzthiazide inhibits sodium reabsorption in the distal convoluted tubule of the nephron, leading to increased excretion of sodium, chloride, water, and other electrolytes, thereby reducing blood volume and blood pressure.

Dosage and Administration

Adult: Typically 25-50 mg once daily, can be adjusted based on response.

Pediatric: Use with caution; dosage determined by medical provider based on condition.

Geriatric: Start at lower doses; monitor closely due to increased risk of electrolyte imbalance and dehydration.

Renal Impairment: Dose adjustment may be necessary; caution in severe impairment.

Hepatic Impairment: Use with caution; monitor for adverse effects.

Pharmacokinetics

Absorption: Well absorbed from gastrointestinal tract.

Distribution: Widely distributed; protein binding approximately 20-40%.

Metabolism: Minimally metabolized.

Excretion: Primarily excreted unchanged by the kidneys.

Half Life: Approximately 2-5 hours.

Contraindications

• Hypersensitivity to benzthiazide or sulfonamides.
• Anuria.

Precautions

• Electrolyte imbalances (hypokalemia, hyponatremia), especially in elderly or dehydrated patients.
• Impaired renal or hepatic function.
• Use with caution in diabetes mellitus, gout, and systemic lupus erythematosus.

Adverse Reactions - Common

• Electrolyte disturbances (hypokalemia, hyponatremia) (Common)
• Hypotension (Common)
• Dizziness, weakness (Common)

Adverse Reactions - Serious

• Electrolyte imbalance leading to cardiac arrhythmias (Serious)
• Blood dyscrasias (rare) (Rare)
• Photosensitivity (rare) (Rare)

Drug-Drug Interactions

• Other antihypertensives, increasing hypotensive effect.
• Lithium, risk of toxicity.
• NSAIDs, may reduce diuretic efficacy and impair renal function.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed, preferably in the morning.
• Notify provider if dizziness, weakness, or muscle cramps occur.
• Maintain adequate hydration and balanced diet, including potassium-rich foods.
• Avoid excessive alcohol and salt intake unless directed.

Special Considerations

Black Box Warnings:

• None currently.

Genetic Factors: None specific.

Lab Test Interference: None known.

Overdose Management

Signs/Symptoms: Severe electrolyte disturbances, dehydration, hypotension.

Treatment: Discontinue medication, restore electrolytes, provide fluid and electrolyte replacement, supportive care.

Storage and Handling

Storage: Store at room temperature, 15-30°C (59-86°F).

Stability: Stable under proper storage conditions.