Losartan

Losartan is a prescription medication that lowers blood pressure and protects your heart and kidneys. It belongs to a class of drugs called angiotensin receptor blockers, or ARBs. Doctors prescribe losartan to help prevent strokes, heart attacks, and kidney problems caused by high blood pressure.

This medication works by relaxing your blood vessels so blood can flow more easily. Lower blood pressure means your heart does not have to work as hard. Losartan comes in tablet form and you take it by mouth, usually once or twice per day.

Your doctor may prescribe losartan alone or combine it with other blood pressure medications. Many people take it for years to manage their condition and reduce their risk of serious health problems. Regular blood tests help make sure the medication is working safely.

• High blood pressure, also called hypertension
• Diabetic kidney disease in people with type 2 diabetes and high blood pressure
• Reducing the risk of stroke in people with high blood pressure and an enlarged heart
• Heart failure when patients cannot tolerate ACE inhibitors
• Protecting kidney function in people with chronic kidney disease

Losartan blocks the action of a hormone called angiotensin II in your body. Angiotensin II normally causes blood vessels to tighten and narrow. When losartan blocks this hormone, your blood vessels relax and widen. This allows blood to flow more easily and lowers your blood pressure.

The medication also reduces strain on your heart and helps protect your kidneys from damage. It takes about 6 hours for losartan to reach its full effect after you take a dose. Most people notice better blood pressure control within 1 week, but it may take 3 to 6 weeks to see the full benefit.

Typical adult doses range from 25 mg to 100 mg taken once daily. Your doctor may start you on a lower dose and increase it gradually based on your blood pressure response. Some people take their dose twice daily if directed by their doctor. For kidney protection in diabetic patients, doses often range from 50 mg to 100 mg once daily. Your doctor will determine the right dose for your specific condition. Always take losartan exactly as prescribed.

• Dizziness or lightheadedness, especially when standing up
• Upper respiratory infections like stuffy nose or sore throat
• Back pain or muscle cramps
• Fatigue or tiredness
• Low blood pressure
• Elevated potassium levels

Serious side effects are rare but require immediate medical attention. Contact your doctor right away if you experience severe dizziness, fainting, signs of high potassium like irregular heartbeat or muscle weakness, or signs of kidney problems like changes in urination. Seek emergency help if you have symptoms of an allergic reaction such as swelling of the face, lips, or throat, or difficulty breathing.

• Potassium supplements and salt substitutes containing potassium may cause dangerously high potassium levels
• Other blood pressure medications may lower blood pressure too much when combined
• NSAIDs like ibuprofen or naproxen can reduce how well losartan works and may harm kidney function
• Lithium levels may increase when taken with losartan
• Diuretics, especially potassium-sparing types, can increase potassium levels
• Do not take losartan if you are pregnant or planning to become pregnant, as it can harm an unborn baby
• People with severe liver disease may need dose adjustments

Regular blood tests are important while taking losartan to make sure the medication is working safely. Your doctor will check your potassium levels because losartan can cause them to rise too high. Kidney function tests including creatinine and eGFR, which measures how well your kidneys filter waste, should be monitored regularly. These tests help catch any kidney problems early.