What It Is

Losartan is an angiotensin II receptor blocker (ARB) used primarily to manage high blood pressure and protect kidney function in patients with diabetes. As a medication that helps to lower blood pressure, it also plays a role in reducing the risk of stroke and heart attack.

Dosage Forms and Strengths

Losartan is available in several dosage forms and strengths:

• Tablets: The most common form, available in strengths of 25 mg, 50 mg, and 100 mg.

Brand and Generic Names

• Brand Names: Cozaar is the most well-known brand name for losartan.
• Generic Names: Losartan is the generic name used internationally.

Indications for Use

Losartan is indicated for:

• Hypertension: To lower high blood pressure in adults and children aged 6 years and older.
• Diabetic Nephropathy: To slow the progression of kidney damage in diabetic patients with hypertension.
• Stroke Prevention: To reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy (enlargement of the heart's left ventricle).

Mechanism of Action

Losartan works by blocking the action of angiotensin II, a hormone that causes blood vessels to constrict (narrow). By inhibiting the binding of angiotensin II to its receptor, losartan causes blood vessels to relax and widen, which leads to a decrease in blood pressure. This mechanism also helps reduce the workload on the heart and protects kidney function.

Administration and Dosage

• Administration: Losartan is administered orally in tablet form.
• Dosage:
  • For hypertension: The usual starting dose is 50 mg once daily, which can be adjusted up to 100 mg once daily based on blood pressure response.
  • For diabetic nephropathy: The usual starting dose is 50 mg once daily, which can be increased to 100 mg daily.
  • For stroke prevention: The recommended dose is 50 mg once daily, with the possibility of increasing to 100 mg based on patient tolerance and blood pressure control.

Effects and Precautions

Effects:

• Therapeutic: Effective in lowering blood pressure and reducing the risk of stroke in high-risk patients. It can also help preserve kidney function in diabetic patients.
• Adverse Effects: Common side effects include dizziness, headache, and fatigue. Some patients may experience hyperkalemia (high potassium levels) or hypotension (low blood pressure).

Precautions:

• Pregnancy: Losartan is not recommended during pregnancy, especially in the second and third trimesters, as it may cause harm to the fetus.
• Renal Function: Caution is advised in patients with renal impairment, as losartan can affect kidney function.
• Interactions: Losartan can interact with other medications, such as potassium-sparing diuretics and certain anti-inflammatory drugs, potentially leading to increased potassium levels or reduced efficacy.

Conclusion

Losartan is a widely used medication for managing hypertension, protecting kidney function in diabetic patients, and reducing the risk of stroke. Its effectiveness is attributed to its ability to block angiotensin II receptors, leading to vasodilation and lowered blood pressure. While generally well-tolerated, it is essential to use losartan with caution in specific populations, including pregnant women and those with renal issues. Proper administration and dosage adjustments are crucial to maximizing its benefits while minimizing potential risks.