Losartan

 Losartan – Full Introduction

Losartan is an angiotensin II receptor blocker (ARB) commonly prescribed for the management of hypertension (high blood pressure), heart failure, and diabetic kidney disease. It helps lower blood pressure and protects vital organs such as the heart and kidneys by blocking the harmful effects of angiotensin II.

Drug Class

• Angiotensin II Receptor Blocker (ARB)

Mechanism of Action

Losartan selectively blocks the angiotensin II type 1 (AT₁) receptors. Angiotensin II normally causes blood vessel constriction and stimulates aldosterone release, leading to increased blood pressure and fluid retention. By blocking these receptors, losartan:

• Relaxes and widens blood vessels

• Lowers blood pressure

• Reduces sodium and water retention

• Decreases strain on the heart

Unlike ACE inhibitors, losartan does not inhibit bradykinin breakdown, which means it is less likely to cause a dry cough.

Therapeutic Uses

• Hypertension

• Heart failure (especially when ACE inhibitors are not tolerated)

• Diabetic nephropathy (type 2 diabetes with proteinuria)

• Stroke risk reduction in hypertensive patients with left ventricular hypertrophy

• Kidney protection in chronic kidney disease

Benefits

• Effective blood pressure control

• Lower risk of ACE-inhibitor–induced cough

• Renal protective effects

• Well tolerated for long-term use

• Reduced cardiovascular morbidity

Common Side Effects

• Dizziness

• Fatigue

• Headache

• Upper respiratory symptoms

• Low blood pressure (hypotension)

Serious but Rare Side Effects

• Hyperkalemia (elevated potassium levels)

• Kidney function deterioration

• Angioedema (very rare)

• Severe hypotension

Contraindications

• Pregnancy (risk of fetal toxicity)

• Bilateral renal artery stenosis

• Severe kidney impairment (use with caution)

• Hypersensitivity to losartan

Conclusion

Losartan is a widely used and effective ARB that provides excellent blood pressure control with fewer side effects than ACE inhibitors. Its protective effects on the heart and kidneys make it a preferred choice in patients with hypertension and diabetes.