If you buy omeprazole yourself for heartburn and acid reflux, take it for at most 7 days; for trouble swallowing, vomiting blood, or black stool, go straight to the hospital

Omeprazole enteric-coated tablets (tablets with a delayed-release coating) have been sold with no prescription since 2022, but the leaflet says not to take them on your own for more than 7 days, and not to take them again within 2 months. Do not take them yourself if swallowing is difficult or painful, if you vomit blood, if there is blood in the stool, or if the stool is black. Those can be signs of something serious. This drug can also hide the symptoms of stomach cancer and delay the diagnosis.

Cost

No money. Take it for the number of days written on the leaflet.

Benefit

Announcement No. 68 of 2022 from the National Medical Products Administration switched omeprazole enteric-coated tablets from prescription to over-the-counter and issued a model leaflet. The listed use is short-term relief of heartburn and acid reflux caused by too much stomach acid. The precautions say: do not use it for more than 7 days, and if the symptoms do not ease, ask a doctor or a pharmacist. Do not take it again within 2 months. If the symptoms come back, get medical care at once. Do not use it when swallowing is difficult or painful, when you vomit blood, when there is blood in the stool, or when the stool is black. Those can be signs of something serious. When alarm symptoms appear, such as clear weight loss, repeated vomiting, trouble swallowing, vomiting blood, or black stool, a malignant tumor has to be ruled out first. The reason is that treatment can hide the symptoms and delay the diagnosis. A person over 55 with a new symptom, or with a symptom that has changed, should ask a doctor. People taking clopidogrel should avoid taking omeprazole at the same time. The reason is in the US leaflet for clopidogrel (Plavix). Omeprazole inhibits the enzyme in the body that converts clopidogrel (CYP2C19). The leaflet says "omeprazole was shown to reduce significantly the antiplatelet activity of Plavix when given concomitantly or 12 hours apart". Taken together, or taken 12 hours apart, clopidogrel's effect against blood clots is clearly weaker either way. The uses written in that leaflet are acute coronary syndrome, a recent heart attack, a recent stroke, and peripheral arterial disease.

Notes

Clopidogrel is a drug that prevents blood clots. People who have had a heart attack or a stroke often take it. Omeprazole makes it weaker, so a person already taking it should ask a doctor first. The grade is B because these are rules on a leaflet. No study has calculated how many incidents following them would prevent. The benefit is rated moderate, as a judgment: what it guards against is a delay in finding stomach bleeding or stomach cancer, but most heartburn and acid reflux are not serious.

Sources · 2

1. 国家药监局关于奥美拉唑肠溶片处方药转换为非处方药的公告（2022年第68号）及附件2《非处方药说明书范本》. nmpa.gov.cn/yaopin/ypggtg/20220826171517123.html
2. Sanofi-Aventis U.S. (2025). PLAVIX (clopidogrel) tablets, US prescribing information, sections 1, 5 and 7（DailyMed）. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?se…