Losartan allergy — how to spot it and what to do

Losartan is an ARB (angiotensin II receptor blocker) used for high blood pressure and some heart problems. Most people tolerate it well, but some have reactions. A true allergy is uncommon. Still, you should know which symptoms mean mild trouble and which are an emergency.

Recognizing losartan allergy

Allergic signs usually show up as skin changes first. Look for a red rash, hives (raised itchy bumps), or sudden itching. Swelling of the lips, face, tongue, or throat is more serious. If you notice tightness in your throat, trouble swallowing, or hoarse voice, treat it like an emergency.

Some reactions people blame on losartan are actually side effects. Dizziness, lightheadedness, high potassium, or kidney changes are known drug effects, not allergies. Cough is more common with ACE inhibitors, not ARBs like losartan. If you’re unsure whether a symptom is an allergy, ask your prescriber.

What to do and safe alternatives

If you have swelling of the face or throat, call emergency services or go to the ER right away. For breathing trouble or fainting, this is life‑threatening. If you get a mild rash or hives, stop taking the medicine and contact your doctor the same day. Your doctor may switch your medicine or suggest an antihistamine if it’s mild.

Are other ARBs safe? It depends on the reaction. For a simple rash, some people can try a different ARB under medical supervision. If you had angioedema (swelling of face/throat) or anaphylaxis, doctors usually avoid all ARBs and ACE inhibitors. In those cases, they’ll pick another class of blood pressure medicine like a calcium channel blocker, thiazide diuretic, or beta blocker.

There’s no standard skin test for losartan allergy, so your doctor may refer you to an allergist. They can review your reaction, your records, and decide if testing or a supervised drug challenge makes sense. If you ever had severe allergic reactions before, ask about carrying an epinephrine auto‑injector (EpiPen) and make sure your medical records show the drug allergy.

Keep a clear record: name the drug (losartan), describe the reaction, and note when it happened. Tell every healthcare provider about it. Report serious reactions to your local drug safety agency or the FDA MedWatch in the U.S. That helps track rare but dangerous events.

Quick checklist: stop the medicine if you suspect an allergic reaction, call your doctor for non‑urgent rashes, go to the ER for breathing or throat swelling, and expect your doctor to recommend safe alternative blood pressure drugs. Asking for an allergy referral is reasonable when the reaction was more than a mild rash.

If you want, I can help draft a short note you can save or show to doctors explaining your losartan reaction. Want that?