Diuretics: Classification, Mechanism, Uses & Side Effects

📌 Introduction

Diuretics are an important class of drugs used to increase urine output and remove excess fluid from the body. They are widely used in conditions like hypertension, edema, and heart failure. This topic is frequently asked in GPAT, DSSSB, and other pharmacy exams, making it essential for students.

Understanding diuretics helps in both exam preparation and clinical practice, as they play a major role in managing fluid balance.

🔍 What are Diuretics?

Diuretics are drugs that increase the excretion of water and electrolytes from the body through urine. They act on different parts of the nephron in the kidney.

They help reduce fluid overload, blood pressure, and swelling.

📝 Classification of Diuretics

Diuretics are classified based on their site and mechanism of action:

• Loop Diuretics
Act on Loop of Henle
Examples: Furosemide, Bumetanide

• Thiazide Diuretics
Act on distal convoluted tubule
Examples: Hydrochlorothiazide

• Potassium-Sparing Diuretics
Prevent potassium loss
Examples: Spironolactone, Amiloride

• Osmotic Diuretics
Increase osmotic pressure
Examples: Mannitol

• Carbonic Anhydrase Inhibitors
Act on proximal tubule
Examples: Acetazolamide

🧬 Mechanism of Action

Each class acts at different sites:

• Loop diuretics → inhibit Na⁺-K⁺-2Cl⁻ transporter
• Thiazides → inhibit Na⁺-Cl⁻ transporter
• Potassium-sparing → block aldosterone or Na⁺ channels
• Osmotic → increase osmotic pressure
• CA inhibitors → inhibit carbonic anhydrase

🩺 Pharmacological Effects

• Increase urine output
• Reduce blood volume
• Lower blood pressure
• Reduce edema

💊 Therapeutic Uses

Diuretics are used in:

• Hypertension
• Edema (heart failure, kidney disease)
• Pulmonary edema
• Glaucoma (mannitol, acetazolamide)
• Ascites

🚨 Side Effects

• Electrolyte imbalance
• Dehydration
• Hypokalemia (loop, thiazide)
• Hyperkalemia (potassium-sparing)
• Dizziness

📑 Important Exam Points

• Furosemide → loop diuretic
• Spironolactone → potassium-sparing
• Mannitol → osmotic diuretic
• Thiazides → hypertension treatment

🎯 Conclusion

Diuretics are essential drugs in managing fluid balance and blood pressure. Understanding their classification, mechanism, uses, and side effects is important for exams and practice. Regular revision and MCQs will help in mastering this topic.

👉 Practice MCQs in evening post