Lansoprazole — a clear, useful guide for people with heartburn and reflux

If you get heartburn, acid reflux, or have been told you have an ulcer, lansoprazole is one of the drugs your doctor may suggest. Known by brand names like Prevacid, lansoprazole is a proton pump inhibitor (PPI) that cuts stomach acid production so you feel better and tissues can heal.

How lansoprazole works and common uses

Lansoprazole blocks the acid pumps in your stomach lining. That lowers the acid level and gives sore tissue a chance to heal. Doctors commonly prescribe it for: gastroesophageal reflux disease (GERD), erosive esophagitis, stomach and duodenal ulcers, and part of treatment plans for H. pylori infection alongside antibiotics. Some people also use it short-term for persistent heartburn that doesn’t respond to antacids.

Depending on where you live, low-dose lansoprazole is also available over the counter for occasional heartburn. Prescription doses tend to be higher and are tailored to the condition being treated.

How to take it, side effects and interactions

Take lansoprazole exactly as your doctor or pharmacist tells you. A few practical rules that help most people: take it before a meal — usually 30 to 60 minutes before breakfast — because that’s when acid pumps are most active. Swallow capsules whole; don’t crush or chew. If you have the soluble packets, mix with water and drink right away.

Typical adult doses: 15–30 mg once daily for mild reflux. For more serious conditions (like erosive esophagitis) a doctor may prescribe 30 mg once daily or higher for a limited period. When used for H. pylori, it’s usually given with two antibiotics and may be taken twice daily. Always follow the prescription on your label.

Common side effects are headache, nausea, stomach pain, diarrhea, and constipation. Most are mild. If you get severe belly pain, persistent diarrhea, signs of low magnesium (muscle cramps, irregular heartbeat), or an allergic reaction — get medical help right away.

Longer-term use of PPIs has been linked in studies to lower magnesium and B12 levels, a small increase in bone fracture risk, and higher chance of certain gut infections. That doesn’t mean everyone will have trouble, but it’s why doctors recheck needs for ongoing treatment rather than leaving someone on a PPI forever without review.

Watch drug interactions: lansoprazole can reduce absorption of meds that need stomach acid (some antifungals and HIV meds) and may affect how blood thinner clopidogrel works. Tell your doctor about all your prescriptions and supplements.

Quick tips: keep to the lowest effective dose, use for the shortest time needed, report new symptoms, and ask about lifestyle steps (weight loss, avoiding late meals, quitting smoking) that often cut reflux without more drugs. If you’re unsure about stopping or switching treatment, talk with your clinician — they’ll help make a safe plan.