Irbesartan: What it Does and How to Use It Safely

Irbesartan is a blood pressure medicine in the angiotensin receptor blocker (ARB) family. Doctors often pick it to lower high blood pressure and to protect the kidneys in people with type 2 diabetes who have protein in their urine. You’ll see it sold as Avapro or as a generic irbesartan tablet.

How to take irbesartan

Irbesartan comes in 75 mg, 150 mg, and 300 mg tablets. A common start dose is 150 mg once a day, but your doctor may begin lower or adjust based on how your blood pressure responds. Take it at the same time each day — with or without food — to build a routine. If you miss a dose, take it when you remember unless it’s almost time for the next dose; don’t double up.

Expect some blood pressure lowering within a few days and fuller effect in 2–4 weeks. Keep taking it even if you feel fine; stopping suddenly can raise your blood pressure again. Pregnant people must not take irbesartan — it can seriously harm the fetus. If pregnancy is possible or confirmed, tell your doctor right away.

What to watch for: side effects and interactions

Common side effects are dizziness, tiredness, or mild stomach upset. Dizziness is most likely when you first start or after a dose increase, so stand up slowly. Less common but important issues include high potassium (hyperkalemia) and reduced kidney function. Your doctor will usually check blood pressure, kidney function (creatinine), and potassium before and after starting treatment.

Watch for signs that need urgent care: fainting, severe dizziness, swelling of the face or throat, or trouble breathing. Those can be allergic or severe reactions and need emergency attention.

Irbesartan interacts with some drugs: avoid combining with ACE inhibitors unless a specialist recommends it, since the combo raises the risk of kidney problems and high potassium. Be cautious with potassium supplements, potassium-sparing diuretics (like spironolactone), and NSAIDs (ibuprofen, naproxen) — these can affect kidney function or potassium. Always tell your provider about all meds and supplements you use.

Buy irbesartan only from licensed pharmacies and use a prescription. If you consider ordering online, stick to verified Canadian or local pharmacies that require a valid prescription — rogue sites may sell counterfeit drugs. Store tablets at room temperature away from moisture and heat; keep them out of reach of children.

Questions for your doctor: ask what target blood pressure you should aim for, how often to check labs, and whether irbesartan is the best option given other conditions you have. With the right follow-up and simple precautions, irbesartan is a practical, well-tolerated option for many people managing high blood pressure.