Hydrochlorothiazide

 Hydrochlorothiazide – Full Introduction

Hydrochlorothiazide (HCTZ) is a thiazide diuretic commonly used in the treatment of hypertension, edema, and certain kidney-related disorders. It lowers blood pressure by promoting the excretion of excess salt and water, thereby reducing blood volume and vascular resistance.

Drug Class

• Thiazide Diuretic

Mechanism of Action

Hydrochlorothiazide acts on the distal convoluted tubule of the nephron, where it inhibits the sodium–chloride (Na⁺/Cl⁻) symporter. This leads to:

• Increased excretion of sodium and chloride

• Increased water loss (diuresis)

• Reduced plasma volume

• Decreased peripheral vascular resistance (long-term effect)

Therapeutic Uses

• Hypertension (first-line or combination therapy)

• Edema associated with heart failure, liver cirrhosis, and kidney disorders

• Nephrogenic diabetes insipidus

• Prevention of calcium-containing kidney stones

• Mild congestive heart failure

Benefits

• Effective and inexpensive antihypertensive

• Enhances the effect of other blood pressure medications

• Long-standing safety record

• Reduces cardiovascular risk in hypertensive patients

Common Side Effects

• Hypokalemia (low potassium)

• Hyponatremia

• Dizziness

• Increased urination

• Hyperuricemia (may precipitate gout)

Serious but Rare Side Effects

• Severe electrolyte imbalance

• Dehydration

• Hyperglycemia

• Photosensitivity reactions

• Pancreatitis (very rare)

Contraindications & Precautions

• Severe renal impairment (ineffective in severe kidney failure)

• Hypersensitivity to sulfonamide-derived drugs

• Gout (use with caution)

• Diabetes mellitus (may increase blood glucose)

• Pregnancy (use only if clearly needed)

Conclusion

Hydrochlorothiazide is a cornerstone drug in the management of hypertension and edema. Its proven efficacy, affordability, and synergistic use with other antihypertensives make it a widely prescribed and reliable medication.