Omeprazole

Gastrointestinal — Proton Pump Inhibitor (PPI)

Nigerian brand names:LosecPrilosecOmedarUlcerexEmzor OmeprazoleZecid

Reviewed by the PMC Medical Team · Promise Medical Centre

Overview

Omeprazole is a proton pump inhibitor (PPI) — a class of drugs that dramatically reduce the amount of acid produced by the stomach. It is one of the most widely prescribed medications in the world and in Nigeria. Omeprazole is highly effective for treating acid reflux (heartburn), peptic ulcers, H. pylori eradication, and conditions of excess stomach acid. PPIs like omeprazole have revolutionised the management of acid-related gastrointestinal disorders. They are generally well tolerated for short-term use, but long-term use is associated with several nutritional deficiencies and should be used at the lowest effective dose for the shortest necessary duration.

Uses

• Gastro-oesophageal reflux disease (GERD / acid reflux): relieves heartburn and prevents oesophageal damage • Peptic ulcer disease: gastric and duodenal ulcers (treatment and prevention) • H. pylori eradication: always as part of triple or quadruple therapy with antibiotics • NSAID-induced ulcers: prevention in patients who must take NSAIDs long-term (especially elderly or high-risk individuals) • Zollinger-Ellison syndrome: rare condition of extreme acid overproduction • Oesophagitis (inflammation of the oesophagus from acid reflux) • Prevention of stress ulcers in critically ill patients • Dyspepsia (indigestion) associated with acid

How to Use

• Standard adult dose for most conditions: 20 mg once daily, taken before the first meal of the day (usually in the morning) • Severe GERD or Zollinger-Ellison syndrome: 40 mg once or twice daily • H. pylori eradication: 20 mg twice daily, combined with antibiotics as prescribed (typically 7–14 days) • Short-term treatment: typically 4–8 weeks • Maintenance therapy: lowest effective dose Take 30 minutes before breakfast on an empty stomach for best effect — the drug must be absorbed before meals to maximise acid suppression Do not crush or chew delayed-release capsules — swallow whole. If you have difficulty swallowing, some formulations can be dissolved in water; check the specific product instructions.

Side Effects

Generally well tolerated. Common side effects: • Headache • Nausea • Diarrhoea or constipation • Abdominal pain and flatulence • Vomiting Side effects of long-term use (months to years): • Vitamin B12 deficiency: PPI reduces stomach acid needed for B12 absorption; check B12 levels annually with long-term use • Magnesium deficiency: can cause muscle cramps, palpitations, seizures; monitor if using >1 year • Calcium malabsorption: long-term use modestly increases the risk of osteoporosis and bone fractures • Increased risk of intestinal infections: reduced stomach acid removes a natural barrier against pathogens including Clostridioides difficile • Hypomagnesaemia (low magnesium) symptoms: muscle spasms, tremors, irregular heartbeat • Rare: interstitial nephritis (kidney inflammation)

Warnings & Precautions

• Long-term use: only continue if there is a clear documented indication; routinely review the need for ongoing treatment with your doctor • Do not use PPIs to "protect the stomach" from every medication without medical advice: overuse is common and harmful • C. difficile infection: stop omeprazole and seek care if you develop severe or persistent diarrhoea during or after antibiotic treatment • Osteoporosis risk: take adequate calcium and vitamin D; consider bone density monitoring with very long-term use • Kidney disease: monitor kidney function with long-term use (rare risk of interstitial nephritis) • Lupus: PPI use has been associated with cutaneous lupus erythematosus (skin lupus) and systemic lupus in rare cases; discuss with your doctor if you develop skin lesions on sun-exposed areas • Liver disease: reduce dose for severe hepatic impairment Important: omeprazole is not a pain reliever and does not treat the underlying causes of ulcers — H. pylori eradication and stopping NSAIDs are essential

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Drug Interactions

• Clopidogrel (antiplatelet drug): omeprazole reduces the effectiveness of clopidogrel: significantly important for patients taking clopidogrel for heart disease. Pantoprazole or esomeprazole are preferred alternatives. • Methotrexate: PPIs may increase methotrexate toxicity • Atazanavir and other antiretrovirals: PPIs reduce their absorption: avoid or use with caution in HIV patients • Ketoconazole and itraconazole: reduced absorption with PPIs (require stomach acid) • Digoxin: PPIs may slightly increase digoxin levels • Iron and vitamin B12: PPI reduces absorption of both; separate dosing or supplement if on long-term PPI • Warfarin: slight increase in anticoagulant effect possible; monitor INR

Storage

• Store at room temperature (below 25–30°C) away from moisture and direct sunlight • Keep in original blister pack until use • Keep out of reach of children

Buy only NAFDAC-registered medications

Nigeria has a significant problem with counterfeit and substandard drugs. Always purchase medications from a licensed pharmacy and check the NAFDAC registration number on the package — verify at nafdac.gov.ng.