Cozaar vs. generic Cozaar (losartan potassium)

Losartan potassium is the generic name for the prescription medication sold under the brand name Cozaar. This medication is also available as a generic drug, which is sometimes called "generic Cozaar." The FDA requires that companies that want to produce generic drugs prove that they're the same as the brand-name medication. 

These generic drugs have to have the same efficacy and safety of the original brand-name prescription medication and be offered in the same strength, dosage form, and route of administration (FDA, 2018).

Generic Cozaar belongs to a class of drugs called angiotensin receptor blockers (ARBs) that also includes the medications valsartan and irbesartan. ARBs are generally used to treat high blood pressure, but they have other "off-label" uses. Losartan is approved by the U.S. Food and Drug Administration (FDA) to treat high blood pressure (hypertension), risk of stroke, and kidney problems from diabetes (diabetic nephropathy) (DailyMed, 2020). 

However, it may not be as effective at reducing stroke risk in Black people with high blood pressure and left ventricular hypertrophy (enlarged heart) than it is in other groups of people (DailyMed, 2020).

Generic Cozaar may also be used off-label after a heart attack to help individuals with heart failure who cannot tolerate ACE inhibitors and treat non-diabetic kidney disease. It may also be used to help prevent a life-threatening complication that's common in people who have Marfan's syndrome, an inherited connective tissue disorder (UpToDate, n.d.). 

Losartan potassium is not an ACE inhibitor. Although ARBs and ACE inhibitors are related and act on the same system in order to lower blood pressure, they interfere with different parts of the system. Angiotensin II is a hormone that causes blood vessels to constrict. 

Too much angiotensin may lead to high blood pressure over time. ARBs block the actions of angiotensin II, whereas ACE inhibitors block an enzyme that makes angiotensin (Burnier, 2001; Sweitzer, 2003). These prescription drugs prevent this squeezing, just in different ways, in order to lower blood pressure (DailyMed, 2020).

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Cozaar recall

Certain lots of generic medications containing losartan were recalled by Torrent Pharmaceuticals Limited in 2019. This company makes generic Cozaar, not the brand-name medication, which is produced by Merck. The recall does not include all lots of these medications produced (FDA, 2019).

These medications were recalled for containing too much of a compound called N-Methylnitrosobutyric acid (NMBA). The FDA allows certain amounts of NMBA in products, but some lots of these medications have passed the cutoff for what is considered an acceptable daily intake (FDA, 2019).

You should contact your pharmacist or healthcare provider for instructions before discontinuing your medication, even if your lot of generic Cozaar was affected. It can be more dangerous to abruptly stop taking your medication than to continue to take losartan products affected by this recall. Your pharmacist may be able to offer an alternative treatment that allows you to stop taking losartan without risking adverse effects (FDA, 2019).

The standard starting dose for adults taking losartan is 50mg, taken once a day in the form of a tablet. The suggested starting dose for each of this medication's FDA-approved uses is the same. Those being treated for high blood pressure with left ventricular atrophy may be prescribed losartan and a diuretic such as hydrochlorothiazide as an adjunct treatment (FDA, 2018).

Some individuals with specific health considerations may be started on a lower dose of losartan (25mg), taken once daily. Those with liver problems or possible volume depletion, a condition caused by the loss of blood sodium that may happen when a patient is also prescribed diuretics (also called "water pills"), will likely be placed on this lower dose to begin (FDA, 2018).

For some people, 50mg of losartan may not be enough to adequately lower high blood pressure. These individuals may have their dosage increased from 50mg to 100mg, taken once daily (FDA, 2018).

The most common possible side effects of losartan include upper respiratory infection, dizziness or lightheadedness, stuffy nose, back pain, chest pain, diarrhea, high levels of potassium, low blood pressure, low blood sugar, and tiredness (FDA, 2018). 

Generic Cozaar may cause a severe allergic reaction—including hives, itching, rash, and trouble breathing. Other serious side effects include low blood pressure (hypotension), changes in kidney function that may include kidney failure in some cases, and high blood potassium (hyperkalemia) (UpToDate, n.d.). Hyperkalemia can be mild or serious, potentially causing heart problems such as arrhythmias (irregular heartbeat), muscle weakness, or paralysis (Simon, 2020). 

Since high blood levels of potassium can be dangerous, you may need to avoid high-potassium foods when taking ARBs such as generic Cozaar. Past research suggests that high dietary potassium may be safe for people with proper kidney function since the kidneys get rid of any excess (Malta, 2016; National Kidney Foundation, 2020). 

But that also means those taking ARBs such as losartan who already have kidney problems such as chronic kidney disease (CKD) may need to limit high-potassium foods such as potatoes, tomatoes, oranges, and bananas (Han, 2013). 

Salt substitutes that use potassium chloride and potassium supplements should also be avoided by anyone taking generic Cozaar. These sources of potassium have not been proven safe like dietary potassium and should be avoided even if you have normal kidney function. Your serum potassium levels may be used to determine how much high-potassium foods should be limited. 

Losartan may also cause serious adverse effects when combined with certain medications. Toxicity may result from combining losartan and lithium. Taking non-steroidal anti-inflammatory drugs (NSAIDs) (such as ibuprofen and naproxen) while on losartan may weaken this antihypertensive drug's effect. Drug interactions such as dangerously low blood pressure may also occur if this prescription medicine is mixed with ACE inhibitors and aliskiren, a different type of medication that's also used to lower blood pressure (DailyMed, 2020). 

Certain people should not take losartan or use this medication with caution. Since the liver breaks down this prescription medication, people with abnormal liver function may develop losartan levels in their system that are too high. Lower doses of the medication may be needed for these individuals. Those with renal artery stenosis, narrowing of the artery to the kidney, may worsen kidney function by taking losartan (DailyMed, 2020).

You should stop taking losartan if you become pregnant as the drug may cause fetal death or injury if taken during the final six months (second and third trimester) of pregnancy. You should not breastfeed when taking losartan as the medication may pass into the breast milk (FDA, 2018). 

Tell your healthcare provider or pharmacist about what other drugs or over-the-counter supplements you're taking before starting so they can advise on your specific case.

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Current version

September 09, 2020

Written by

Linnea Zielinski

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.