What does Losartan potassium do?

Published May 9th, 2020 by Bridget Reed
Fact Checked by
Chris Riley
Updated Date: Jul 7th, 2022

According to the Center for Disease Control (CDC), about 45 percent of American adults, or 108 million people, currently suffer from high blood pressure, also known as hypertension. High blood pressure is at epidemic levels in the United States thanks to the sedentary lifestyles and high-fat western diets that are customary for many Americans, but the condition can also be influenced by stress, medications, and medical conditions. Because the condition is heavily influenced by lifestyle, doctors generally advise hypertensive patients suffering from hypertension to make serious lifestyle changes, like eating right and exercising more. For some people, however, lifestyle changes alone will not be enough to bring their high blood pressure down to a normal level, and treatment with prescription medication may be warranted. Getting high blood pressure under control is critical because the condition is known as the “silent killer” since many people do not know they have it until they experience a heart attack or stroke as a result. Today, high blood pressure is the leading cause of cardiovascular disease-related deaths in the United States. Losartan potassium is a commonly prescribed high blood pressure drug that can be used to lower high blood pressure in conjunction with lifestyle changes. 

What Is Losartan Potassium?

Manufactured under the brand name Cozaar, losartan potassium belongs to a class of prescription drugs called angiotensin II receptor antagonists (ARBS) or angiotensin II receptor blockers and was first approved for medical use in the United States by the Food and Drug Administration (FDA) in 1995. The generic form of losartan potassium as an antihypertensive was released to the public in 2010, and the medication is available by prescription only.  

What Does Losartan Potassium Do?

Angiotensin II receptor antagonists like losartan potassium work by blocking the action of angiotensin II, a chemical that causes the blood vessels to narrow and tighten. These medications lower blood pressure by blocking angiotensin II from absorption, allowing the blood vessels to relax and open. Losartan potassium primarily treats high blood pressure, but it can also be used to help protect the kidneys from damage caused by diabetes, known as diabetic nephropathy,  in patients who also have high blood pressure. The medication helps to lower the risk of strokes in patients with an enlarged heart or high blood pressure at risk of heart disease.  

High Blood Pressure

Blood pressure is defined as the force with which blood presses against the walls of the blood vessels as the heart beats. If your blood pressure is too high, it can cause damage to the blood vessels, and if it is too low, blood is unable to reach all of your organs and extremities. High blood pressure, also called hypertension, is characterized by the blood pushing too forcefully against the walls of the blood vessels consistently over an extended period of time. Our blood pressure goes up when we work out or during times of stress, but it normally goes back down to normal levels. High blood pressure is consistent over time. When people suffer from high blood pressure, their hearts and blood vessels must work at an increased effort level and less efficiently in order to provide the tissues and organs with the blood they need to function. When not carefully managed, high blood pressure can cause the blood vessels to narrow due to microtears in the walls of the arteries. As the blood vessels become more narrow, blood is further prevented from reaching the different areas of the body, causing blood pressure to rise further. Doctors can only point to the specific cause of high blood pressure in about five percent of cases, where the condition is caused by medication or an underlying health condition. The other 95 percent of cases have no obvious causes and are primarily influenced by lifestyle factors and genetics.  

Diabetic Nephropathy

Diabetic kidney disease, or diabetic nephropathy, affects approximately 25 percent of people with diabetes over the course of their lifetime. Diabetes and high blood pressure impact the ability of the kidneys to remove waste products and extra fluid from the body, which causes kidney problems. Over time, diabetic nephropathy can lead to severe kidney disease or kidney failure, which is a life-threatening condition that requires dialysis or a kidney transplant. Diabetic nephropathy is best managed by living a healthy lifestyle and carefully managing the treatment of diabetes and high blood pressure. 

What Are the Benefits of Losartan Potassium?

Use of losartan potassium has several benefits:

  • Losartan potassium has been around since the 1990s and has developed a reputation as a reliable, effective drug for treating high blood pressure and diabetic nephropathy. 
  • Losartan potassium is more effective in reducing cardiovascular death, stroke, and myocardial infarction when compared to other blood pressure medications, such as atenolol.
  • The medication reduces the risk of new-onset diabetes in patients with high blood pressure who take the medication.
  • Losartan potassium is available in a generic form and is highly affordable and accessible for most patients.

What Risks Are Associated with Losartan Potassium?

Although there are many benefits associated with losartan potassium, as listed above, taking the medication also poses some risks. Always read the drug information before taking a medication. Risks associated with losartan potassium include:

  • Patients who have kidney disease or type 2 diabetes should not take losartan potassium with medications that contain aliskiren, such as Amturnide, Tekturna, Tekamlo, and Valturna.
  • There is a high risk of fetal injury and morbidity associated with the use of losartan potassium in pregnant women. Pregnant and breastfeeding women should not take losartan potassium. 
  • Dehydration may occur and can be dangerous, leading to low blood pressure. Patients should tell their doctors if they become sick, especially if they have vomiting or diarrhea that will not stop. 
  • Patients with low blood pressure should use caution when taking this medication. 

What Dose of Losartan Potassium Should I Take?

The dose of losartan potassium that your doctor prescribes will vary depending on the condition being treated, your age, overall health, and other medical conditions. Patients taking losartan potassium for diabetic nephropathy may be prescribed a starting dose of 50 mg orally once per day before switching to a maintenance dose of between 25 to 100 mg taken orally in 1 or 2 doses per day. Patients taking losartan potassium for high blood pressure are often prescribed an initial dose of 50 mg taken orally once per day. After the initial dose, a maintenance dose of 25 to 100 mg will be taken orally in 1 or 2 doses. Overall, be sure to follow the medical advice of your doctor including informing them about any missed doses and storing the medication at room temperature. 

What Are the Side Effects of Losartan Potassium?

Side effects associated with losartan potassium are categorized as either common or less common, and some may require medical attention. Common side effects associated with losartan potassium that usually do not need medical attention include:

  • Body aches or back pain
  • Continuing ringing or buzzing in the ears
  • Constipation
  • The feeling of constant movement of self or surroundings
  • Headache, sometimes severe or throbbing
  • Inability to have or keep an erection
  • Irritability
  • Ear congestion
  • Feeling sad or empty
  • Hearing loss
  • Increased sun sensitivity
  • Lack of appetite
  • Loss of sex drive
  • Loss of voice
  • Sensation of spinning
  • Sneezing
  • Stuffy or runny nose
  • Trouble sleeping
  • Chills
  • Loss of interest or pleasure
  • Redness or other skin discoloration
  • Severe sunburn
  • Sore throat
  • Trouble sleeping

As long as these common side effects are mild, they should go away within a few days or weeks. If side effects persist or allergic reactions occur, talk to your doctor.
Some side effects of losartan potassium do require medical attention. Check with your health care provider immediately if you experience any of the following serious adverse effects while taking losartan potassium:

  • Blurred vision
  • Confusion
  • Weakness or heaviness of the legs
  • Burning, crawling, itching, numbness, prickling, tingling feelings, or “pins and needles”
  • Difficulty breathing
  • Dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • Fast heart rate, irregular heartbeat or chest pain
  • Dizziness
  • Fainting
  • Nausea or vomiting
  • Numbness or tingling in the hands, feet, or lips
  • Sweating
  • Nervousness
  • Stomach pain
  • Unusual tiredness or weakness

Is Losartan Potassium Safe for Women Who Are Pregnant or Breastfeeding?

Losartan potassium is not safe for pregnant women and may not be safe for breastfeeding women. Losartan potassium is considered highly dangerous for pregnant women and is categorized as pregnancy category D by the FDA for all trimesters, meaning that studies in pregnant women have shown that there is a risk to the fetus when taking losartan potassium. Specifically, losartan potassium is associated with fetal death and morbidity when used in the second and third trimester. Mothers who are going to breast-feed should talk to their doctors if taking losartan potassium while breastfeeding, as conclusive research regarding risks medication transfer from breast milk to the infant has not been conducted. 

Who Should Not Take Losartan Potassium?

Losartan potassium is an effective drug for the treatment of high blood pressure and diabetic nephropathy, but it is not right for everyone. The following groups of people should not take losartan potassium:

  • Women who are pregnant, nursing, or planning to become pregnant should not take losartan potassium due to the risk of injury or death to the unborn baby associated with the medication. Women should use effective birth control while taking losartan potassium. 
  • People who are allergic to losartan potassium should not take the medication, nor should people taking medication that contains aliskiren (Amturnide, Tekturna, Tekamlo, Valturna) to avoid problematic drug interactions. 
  • Patients should not use salt substitutes or potassium supplements to improve potassium levels while taking this medication.
  • Patients should avoid all use of non-steroidal anti-inflammatory drugs and NSAIDs like naproxen and ibuprofen while taking this medication.
  • Patients with kidney disease, liver disease, congestive heart failure, electrolyte imbalances, or a history of dehydration should make sure to give their doctors a complete medical history prior to taking this medication.

Put drug prices & coupons in your pocket!

We'll text you a link to download our free Android or iPhone app