Losartan is an angiotensin II receptor blocker (ARB) widely used in the treatment of high blood pressure (hypertension), heart failure, and kidney disease associated with diabetes. Unlike ACE inhibitors, which block the conversion of angiotensin I to angiotensin II, losartan directly blocks the binding of angiotensin II to its receptor (AT1 receptor). This results in vasodilation, reduced sodium and water retention, and lower blood pressure without causing the persistent cough often seen with ACE inhibitors. Losartan was the first ARB to be approved for clinical use and has a long track record of safety and effectiveness worldwide.
By lowering blood pressure and reducing strain on the cardiovascular system, losartan decreases the risk of heart attack, stroke, and progression of kidney damage. It is especially valuable in patients with type 2 diabetes and proteinuria (excess protein in the urine), as it slows the decline of kidney function and can delay the need for dialysis or kidney transplantation. Clinical trials such as the LIFE (Losartan Intervention For Endpoint reduction) study have demonstrated benefits not only in reducing blood pressure but also in improving long-term cardiovascular outcomes.
Losartan is typically prescribed once daily and is available in generic form, making it an affordable option for patients worldwide. It is generally well tolerated, though monitoring is necessary for kidney function and potassium levels, particularly in patients with pre-existing kidney disease or those taking potassium supplements. As part of the ARB class, losartan is considered interchangeable with other ARBs in many clinical contexts, but it remains a first-line choice due to its long history of use and robust evidence base.
Always follow the prescribing doctor’s instructions and never adjust the dose on your own.
Patients should be instructed to report swelling, difficulty breathing, or persistent dizziness promptly.
Clinicians should assess comorbidities and medications to minimise risks.
Patients should maintain an up-to-date medication list and review it regularly with their healthcare provider.
Overdose: Symptoms may include marked hypotension, dizziness, rapid or slow heart rate, and fainting. Seek emergency medical care immediately. Supportive treatment such as IV fluids may be required. There is no specific antidote.
Missed dose: Take it as soon as remembered unless it is almost time for the next dose. Do not take two doses at once.
Patients should be educated to avoid abrupt discontinuation and to contact their clinician if multiple doses are missed, as this may reduce blood pressure control.
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