Losartan Safety: What You Need to Know About Side Effects, Risks, and Alternatives

When you’re taking losartan, a common angiotensin receptor blocker used to treat high blood pressure and protect kidneys in diabetics. Also known as Cozaar, it’s one of the most prescribed blood pressure meds in the U.S. and Europe—but safety isn’t automatic, even if your doctor says it’s fine. Many people assume that because it’s been around for decades, it’s completely safe. But that’s not true. Like every drug, it has real risks, and not everyone knows them.

One of the biggest concerns with losartan, an angiotensin receptor blocker that blocks the hormone angiotensin II to relax blood vessels is how it affects your kidneys and potassium levels. If you already have kidney disease or are on other meds like potassium supplements or NSAIDs, your risk of high potassium goes up. That can lead to irregular heartbeat, even without symptoms. Studies show about 1 in 20 people on losartan develop mild hyperkalemia, and it’s often missed because there’s no warning sign until it’s serious. You need regular blood tests—not just a yearly checkup.

Another hidden risk is drug interactions, how losartan reacts with other medications you might be taking. Grapefruit juice doesn’t affect it like it does statins, but lithium, NSAIDs like ibuprofen, and even some diuretics can change how losartan works—or make side effects worse. If you’re on more than one blood pressure pill, you’re at higher risk. And if you’re pregnant? Losartan can cause fetal injury or death. It’s not just a "don’t take while pregnant" warning—it’s a hard stop.

Side effects aren’t rare either. Dizziness? Common. Dry cough? Less common than with ACE inhibitors, but still happens. Fatigue? Yes. And in rare cases, angioedema—swelling of the face, lips, or throat—can occur. It’s not common, but if it does, you need to stop it immediately and get help. Most people tolerate losartan well, but that doesn’t mean you’re immune. The key is knowing your body and watching for changes.

People often ask if there are better or safer alternatives. other angiotensin receptor blockers, like valsartan or irbesartan work similarly, but some have slightly different side effect profiles. If you can’t tolerate losartan, switching might help. Or you could consider ACE inhibitors, calcium channel blockers, or thiazide diuretics—each with their own pros and cons. It’s not about which one is "best," but which one fits your health, lifestyle, and other conditions.

What you’ll find below isn’t just a list of articles. It’s a practical collection of real comparisons and safety guides based on actual patient experiences and clinical data. You’ll see how losartan stacks up against other blood pressure drugs, what to do if you experience side effects, and how to avoid dangerous interactions with common meds and supplements. No fluff. No marketing. Just clear, usable info to help you stay safe and in control of your treatment.