Lifestyle

Stomach Trouble, Headache, or Unusual Tiredness on a Common Heartburn Pill Can Be Signs to Tell Your Doctor. What Older Adults Should Know

By Curtis Jones · November 6, 2026

Omeprazole is one of the medicines doctors and pharmacists most often recommend for heartburn and related acid problems. MedlinePlus says it belongs to a class called proton-pump inhibitors, and that it works by decreasing the amount of acid the stomach makes. Prescription versions treat GERD, help an injured esophagus heal, treat ulcers and help clear H. pylori when combined with other drugs. Over-the-counter versions are aimed at frequent heartburn in adults.

Most people who take it tolerate it. The points below are signs and precautions to talk over with a doctor or pharmacist, not reasons to stop the pill on your own. MedlinePlus is clear: continue taking prescription omeprazole even if you feel well, and do not stop without talking to your doctor.

Common side effects to report if they are severe or do not go away. MedlinePlus lists:

Stomach and bowel trouble. Constipation, gas, nausea, diarrhea or vomiting.

Headache. Also listed among the common effects that deserve a call if they linger or feel severe.

Serious symptoms that need a call right away, or emergency care. MedlinePlus says to seek help for blistering, peeling or bleeding skin; rash, hives, swelling of the face, lips, tongue or throat, or trouble breathing; irregular, fast or pounding heartbeat, muscle spasms, shaking, excessive tiredness, lightheadedness, dizziness or seizures; severe diarrhea with watery stools, stomach pain or fever that does not go away; new or worsening joint pain, or a rash on the cheeks or arms that is sensitive to sunlight; and changes in urination, blood in the urine, fatigue, loss of appetite or related problems.

The heartbeat, muscle spasm, shaking, tiredness, lightheadedness and seizure cluster can signal low magnesium, which is why those symptoms sit together on the serious list. Watery diarrhea that will not quit is also on that list. Treat it as one reason to call, not as a full diagnosis of any specific infection.

Longer use brings other questions. MedlinePlus says people who take proton-pump inhibitors such as omeprazole may be more likely to fracture a wrist, hip or spine than people who do not, and may develop fundic gland polyps on the stomach lining. Those risks are highest with high doses or use for a year or longer. Talk with the doctor about the risk rather than guessing.

A few practical rules from the same page:

Do not use the over-the-counter product for instant relief. It may take 1 to 4 days to feel the full benefit.

Do not take nonprescription omeprazole longer than 14 days, or more often than once every 4 months, without talking to a doctor.

Tell the doctor about other medicines and supplements, including iron and St. John’s wort, before starting or stopping anything.

Before nonprescription use, tell a doctor about heartburn lasting 3 months or longer, chest or shoulder pain, shortness of breath, unexplained weight loss, trouble swallowing, or black or bloody stools. Those can point to problems the over-the-counter pill will not fix.

If something feels off, write down when it started, how long it lasts and what else you take, then call the office that prescribed the medicine or the pharmacist who sold it. Do not change the dose or quit on your own.

This article is for general information and is not medical advice. Do not stop or change any medicine without talking with the doctor who prescribed it. This article was produced with the assistance of AI and fact-checked against the sources cited by LightWave Reports.