Omeprazole Dosage Guide: How Much to Take & When

If you’ve been prescribed omeprazole or bought it over the counter, you probably wonder how much you should actually take. The good news is the dosing is pretty straightforward once you know the condition you’re treating and a few personal factors. Below you’ll find the most common doses, what to adjust if you’re older or have kidney issues, and some handy tips to get the best result.

Standard adult doses

For most adults, omeprazole comes in 20 mg or 40 mg capsules. The typical dosing schedule looks like this:

• Heartburn or occasional acid reflux: 20 mg once daily before the first meal of the day.
• Frequent heartburn (GERD) or mild to moderate erosive esophagitis: 20 mg once daily, taken for 4‑8 weeks.
• Severe erosive esophagitis, Zollinger‑Ellison syndrome, or healing after ulcer surgery: 40 mg once daily, sometimes split into two 20 mg doses (morning and evening) for better control.

Most doctors recommend taking the pill with a glass of water and waiting at least 30 minutes before eating. This lets the drug reach the stomach’s lining while it’s still mostly empty, which improves its effectiveness.

Special situations and tips

Kids and teens: Omeprazole is not usually the first choice for children under 12. If a pediatrician does prescribe it, the dose is weight‑based—about 0.5 mg per kilogram of body weight, up to a maximum of 20 mg per day. Always follow the doctor’s exact instructions.

Older adults: People over 65 may need a lower dose, especially if they have liver problems. Starting with 20 mg and monitoring symptoms works for most seniors.

Kidney or liver impairment: No major dose change is required for mild kidney issues, but severe liver disease may call for a reduced dose. Talk to a pharmacist if you have chronic organ problems.

Missing a dose: If you forget, take it as soon as you remember—provided it’s still at least 5 hours before your next scheduled dose. Otherwise, skip it and continue with your regular schedule. Double‑dosing can increase side‑effects without added benefit.

How long to stay on it? Most short‑term uses (like treating a bout of heartburn) last 4‑8 weeks. For chronic conditions like GERD, doctors may keep you on a low dose for months or even years, but they’ll usually reassess every 6‑12 months.

Potential side effects: Common issues include headache, mild stomach pain, or diarrhea. If you notice severe abdominal pain, dark stools, or persistent vomiting, call your doctor right away—these could signal a rare but serious problem.

Finally, avoid mixing omeprazole with certain drugs that rely on stomach acidity for absorption, such as ketoconazole or certain HIV meds. A quick chat with your pharmacist can prevent unwanted interactions.

In a nutshell, start with the dose your doctor gave you, take it before a meal, and stick to the schedule. Adjustments are only needed for kids, seniors, or specific health conditions. If symptoms don’t improve after a few weeks, or if you experience unusual side effects, reach out to your healthcare provider for a possible dose tweak.