Hydrochlorothiazide

Introduction

• Generic Name: Hydrochlorothiazide (HCTZ)
• Brand Names: Microzide, Hydrodiuril, Esidrix
• Pharmacological Class: Thiazide Diuretic
• Mechanism of Action: Inhibits sodium and chloride reabsorption in the distal tubules of the kidney, leading to increased urine production and reduced blood volume, thereby lowering blood pressure.

Indications

• Primary Use: Treatment of hypertension (high blood pressure).
• Other Uses: Management of edema (fluid retention) associated with heart failure, liver cirrhosis, or kidney disorders. Sometimes used for nephrolithiasis (kidney stones) prevention.

Dosage

• Adults:
  • Hypertension: Typically 12.5 mg to 25 mg once daily. Maximum dose: 50 mg/day.
  • Edema: 25 mg to 100 mg daily, in a single or divided dose.
• Elderly: Start at a lower dose due to increased risk of dehydration and electrolyte imbalance.
• Children: 1 mg/kg/day divided into 1 or 2 doses (maximum 37.5 mg/day).

Administration

• Method: Oral intake.
• Precautions: Should be taken in the morning to avoid nocturia (frequent nighttime urination). Can be taken with or without food.

Forms Available

• Tablets: 12.5 mg, 25 mg, 50 mg
• Capsules (Microzide): 12.5 mg

Side Effects

• Common: Increased urination, dizziness, low blood pressure, muscle cramps, dry mouth.
• Less Common: Nausea, headache, electrolyte imbalances (low potassium, low sodium).
• Rare but Serious: Severe hypokalemia, arrhythmias, pancreatitis, gout, kidney dysfunction.

Warnings

• Black Box Warning: None.
• Contraindications: Anuria (no urine output), severe kidney failure, known hypersensitivity to sulfonamide-derived drugs.

Precautions

• General: Monitor electrolyte levels regularly, especially potassium, sodium, and magnesium.
• Health Conditions: Use caution in patients with diabetes, gout, and chronic kidney disease.

Interactions

• Medications:
  • Increased toxicity with: Lithium, NSAIDs, corticosteroids.
  • May enhance effects of: Other antihypertensives.
  • Risk of hypokalemia with: Loop diuretics, corticosteroids.
• Food: High-sodium diets may reduce effectiveness.

Monitoring Parameters

• Blood Pressure: Regular monitoring to assess therapeutic effect.
• Electrolytes: Regular blood tests to check potassium, sodium, and kidney function.
• Kidney Function: Monitor creatinine and BUN (blood urea nitrogen) levels.

Use in Children

• Guidelines: Approved for pediatric use, with weight-based dosing. Monitor for dehydration and electrolyte imbalance.

Use in Pregnancy

• FDA Category: B. Generally avoided due to risk of fluid shifts and electrolyte disturbances in the fetus.

Use in Elderly

• Considerations: Higher risk of dehydration and electrolyte imbalance. Monitor closely.

Use in Kidney Disease

• Adjustments:
  • Avoid in severe renal impairment (eGFR <30 mL/min).
  • Requires dose adjustments in mild-to-moderate renal disease.

Use in Liver Disease

• Caution: Can worsen liver dysfunction in cirrhosis. Monitor for hepatic encephalopathy.

Patient Counselling Points

• Medication Use: Take in the morning to avoid frequent urination at night.
• Side Effects: Report muscle cramps, dizziness, or signs of dehydration (dry mouth, confusion).
• Lifestyle: Maintain a balanced diet with sufficient potassium intake (e.g., bananas, oranges, spinach).

Table of Brand Names, Manufacturer, and Prices in USD

15 FAQs with Answers

1. What is Hydrochlorothiazide used for? – Mainly for high blood pressure and fluid retention.
2. How does Hydrochlorothiazide work? – It helps your kidneys remove excess salt and water, reducing blood pressure.
3. When should I take Hydrochlorothiazide? – Take it in the morning to avoid waking up frequently at night.
4. Can Hydrochlorothiazide cause dehydration? – Yes, it increases urine output, which can lead to dehydration.
5. Is Hydrochlorothiazide safe during pregnancy? – Generally avoided unless absolutely necessary.
6. What are signs of low potassium with Hydrochlorothiazide? – Muscle cramps, weakness, irregular heartbeat.
7. Can I drink alcohol while taking Hydrochlorothiazide? – Alcohol can worsen dizziness and should be used cautiously.
8. How long does it take for Hydrochlorothiazide to work? – The antihypertensive effect begins within 2 hours.
9. What should I do if I miss a dose? – Take it as soon as possible unless it’s close to the next dose.
10. Does Hydrochlorothiazide interact with other medications? – Yes, caution with NSAIDs, lithium, and other diuretics.
11. What should I avoid while taking Hydrochlorothiazide? – Excessive sun exposure, alcohol, and high-sodium diets.
12. Can Hydrochlorothiazide affect kidney function? – It may worsen kidney function if dehydration occurs.
13. Does Hydrochlorothiazide help with weight loss? – It reduces water weight but is not a weight-loss medication.
14. Who should not take Hydrochlorothiazide? – Patients with severe kidney disease or sulfa allergies.
15. How is Hydrochlorothiazide different from furosemide (Lasix)? – Hydrochlorothiazide is milder and used mainly for hypertension, while furosemide is a stronger diuretic for severe fluid retention.