What is Losartan (angiotensin II receptor antagonist)?

From the Guidelines

Losartan is an angiotensin II receptor antagonist (ARB) that is commonly prescribed to treat high blood pressure (hypertension) and protect the kidneys in people with type 2 diabetes. It works by blocking the action of angiotensin II, a natural substance that narrows blood vessels and causes blood pressure to rise. By blocking these receptors, Losartan relaxes blood vessels, allowing blood to flow more easily and lowering blood pressure.

Key Points

• The typical starting dose is 50 mg once daily, which may be increased to 100 mg daily if needed for blood pressure control 1.
• For patients with reduced kidney function or those taking diuretics, a lower starting dose of 25 mg may be recommended.
• Common side effects include dizziness, fatigue, and occasionally high potassium levels.
• Losartan should not be taken during pregnancy as it can cause harm to the developing fetus.
• Patients should take this medication consistently at the same time each day and should not stop taking it without consulting their healthcare provider, even if they feel well, as hypertension is often symptomless but can lead to serious health problems if left untreated.

Benefits and Risks

• Losartan has been shown to reduce the risk of cardiovascular events and mortality in patients with hypertension and type 2 diabetes 1.
• It also has renoprotective effects, reducing the progression of kidney disease in patients with type 2 diabetes and nephropathy 1.
• However, Losartan may cause adverse effects such as hyperkalemia and acute kidney injury, particularly when used in combination with other renin-angiotensin-aldosterone system inhibitors 1.

Clinical Use

• Losartan is often used in combination with other antihypertensive medications to achieve optimal blood pressure control.
• It is also used to protect the kidneys in patients with type 2 diabetes and nephropathy.
• The choice of Losartan as a treatment option should be based on individual patient characteristics, including kidney function, blood pressure, and presence of other comorbidities.

From the FDA Drug Label

Losartan potassium is an angiotensin II receptor blocker acting on the At 1 receptor subtype. Losartan potassium, a non-peptide molecule, is chemically described as 2-butyl-4-chloro-1-[ p-( o-1 H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt Its empirical formula is C 22H 22CIKN 6O, and its structural formula is: Losartan potassium is a white to off-white free-flowing crystalline powder with a molecular weight of 461. 01.

Losartan is an angiotensin II receptor antagonist that works by blocking the action of angiotensin II, a potent vasoconstrictor, at the AT1 receptor subtype.

• It is used to treat hypertension, diabetic nephropathy, and to reduce the risk of stroke in patients with hypertension and left ventricular hypertrophy.
• The drug is available in tablet form for oral administration, containing 25 mg, 50 mg, or 100 mg of losartan potassium.
• Losartan potassium tablets are freely soluble in water, soluble in alcohols, and slightly soluble in common organic solvents. 2

From the Research

What is Losartan

• Losartan is an angiotensin II receptor antagonist, which means it blocks the action of angiotensin II, a potent vasoconstrictor, at its receptor site 3, 4, 5, 6, 7.
• It is used to treat hypertension (high blood pressure) and has been shown to be effective in reducing blood pressure in patients with mild to moderate hypertension 4, 5.
• Losartan is also used to treat diabetic nephropathy, a type of kidney disease that occurs in people with diabetes, and has been shown to slow the progression of kidney disease in these patients 3, 6.

Mechanism of Action

• Losartan works by blocking the action of angiotensin II at its receptor site, which leads to a decrease in blood pressure and a reduction in the progression of kidney disease 3, 4, 6.
• The drug is converted to its active metabolite, E-3174, which is a more potent antagonist of the angiotensin II receptor 4, 5.

Pharmacokinetics

• Losartan is rapidly absorbed after oral administration and reaches maximum concentrations within 1-2 hours 4.
• The drug has a terminal half-life of 6-9 hours and is excreted primarily in the urine 4.
• Losartan does not have significant drug-drug interactions with other medications, including hydrochlorothiazide, warfarin, and digoxin 4.

Clinical Uses

• Losartan is used to treat hypertension, diabetic nephropathy, and heart failure 3, 4, 6.
• The drug has been shown to be effective in reducing blood pressure and slowing the progression of kidney disease in patients with diabetic nephropathy 3, 6.
• Losartan is also used to treat patients with heart failure and has been shown to improve symptoms and reduce hospitalization rates in these patients 4.