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Key Facts
- Drug Class
- Proton pump inhibitor (PPI)
- Prescription
- Over the counter
- NAFDAC Status
- NAFDAC Registered
- Forms
- Capsule, Tablet, Injection
- Price Range
- ₦200 - ₦5,000
- WHO Essential
- Yes
What is Omeprazole?
Omeprazole is one of the most commonly used medications in Nigeria, widely known as "the ulcer drug." Walk into virtually any pharmacy or patent medicine store across the country — from Ikeja to Kano, Enugu to Port Harcourt — and you will find omeprazole on the shelf. It belongs to a class of drugs called proton pump inhibitors (PPIs), which work by reducing the amount of acid produced in the stomach. This makes it highly effective for treating peptic ulcers, acid reflux, and other conditions caused by excess stomach acid. In Nigeria, where the prevalence of peptic ulcer disease is high, omeprazole has become a household name.
Omeprazole works by irreversibly blocking the hydrogen-potassium ATPase enzyme system (the proton pump) in the stomach lining, which is the final step in acid production. By shutting down these acid pumps, omeprazole dramatically reduces stomach acid secretion, allowing ulcers to heal and preventing new ones from forming. It is a key component of the triple therapy regimen used to eradicate Helicobacter pylori (H. pylori), a bacterium responsible for the majority of peptic ulcers in Nigeria. The triple therapy typically combines omeprazole with two antibiotics — amoxicillin and either metronidazole or clarithromycin — and is widely prescribed across the country.
Omeprazole is available in Nigeria under several brand names including Losec (the original brand by AstraZeneca), Emzor Omeprazole (locally manufactured), Risek, and Omez. All legitimate brands must carry a NAFDAC registration number. While omeprazole is available over the counter in most Nigerian pharmacies, it is important to understand that self-medicating for persistent stomach pain without proper diagnosis can mask serious conditions including stomach cancer. If your symptoms persist beyond two weeks, you should see a doctor for proper evaluation.
What is Omeprazole used for?
In Nigeria, Omeprazole is commonly used for:
- Treatment of stomach (gastric) and duodenal ulcers — the most common reason Nigerians take omeprazole
- Gastroesophageal reflux disease (GERD), commonly known as acid reflux or heartburn
- H. pylori eradication as part of triple therapy (omeprazole + amoxicillin + metronidazole or clarithromycin)
- Prevention of stomach ulcers caused by regular use of NSAIDs such as ibuprofen, diclofenac, and aspirin
- Zollinger-Ellison syndrome and other conditions involving excessive stomach acid production
- Relief of symptoms of dyspepsia (indigestion) and epigastric pain
Dosage
IMPORTANT
Always follow your doctor's or pharmacist's instructions. The information below is for general reference only.
Adults
For peptic ulcer: 20mg once daily for 4 to 8 weeks. For GERD: 20mg once daily for 4 weeks, may be increased to 40mg if needed. For H. pylori triple therapy: 20mg twice daily for 7 to 14 days alongside antibiotics. For NSAID-associated ulcer prevention: 20mg once daily. Take the capsule 30 minutes before a meal, preferably in the morning before breakfast.
Children
Omeprazole is generally used in children over 1 year of age under medical supervision. Dosing is weight-based: children weighing 10-20kg may take 10mg once daily, while those over 20kg may take 20mg once daily. Always consult a paediatrician before giving omeprazole to a child.
Elderly
Standard adult doses are generally appropriate for elderly patients. However, elderly individuals with liver impairment may require lower doses. A maximum daily dose of 20mg is recommended for those with severe liver problems.
Omeprazole capsules should be swallowed whole with a glass of water — do not crush, chew, or open the capsules, as the granules inside are specially coated to resist stomach acid. Take it 30 minutes before meals for maximum effectiveness. If you are on triple therapy for H. pylori, complete the full course of antibiotics even if you feel better. Do not take omeprazole continuously for more than 8 weeks without medical review.
Side Effects
Common side effects
- •Headache — one of the most frequently reported side effects
- •Diarrhoea or constipation
- •Nausea, stomach pain, or flatulence (gas)
- •Dizziness
Serious side effects — seek medical help immediately
- Vitamin B12 deficiency with long-term use (more than 3 years), which can cause tiredness and numbness
- Increased risk of bone fractures (hip, wrist, spine) with long-term, high-dose use
- Clostridium difficile-associated diarrhoea — severe, persistent, watery diarrhoea that requires medical attention
- Low magnesium levels (hypomagnesaemia) with prolonged use, which can cause muscle cramps and irregular heartbeat
- Severe allergic reactions including skin rash, swelling, and difficulty breathing — rare but seek emergency care
When to see a doctor
See a doctor if you experience persistent diarrhoea, severe stomach pain, unexplained weight loss, difficulty swallowing, vomiting blood, or black tarry stools while taking omeprazole. These could indicate a more serious condition that needs investigation. Also consult a doctor if your symptoms do not improve after two weeks of treatment, or if you have been taking omeprazole for more than 8 weeks without medical supervision.
Warnings & Precautions
Do not take Omeprazole if you have:
- Do not take if you have a known allergy to omeprazole or any other proton pump inhibitor (such as esomeprazole, lansoprazole, or pantoprazole)
- Do not take with the HIV medication rilpivirine (Edurant) or nelfinavir, as omeprazole significantly reduces their effectiveness
- Exercise caution if you have severe liver disease — a reduced dose may be necessary
Drug interactions
- •Clopidogrel (Plavix) — omeprazole reduces the effectiveness of this blood-thinning medication; your doctor may switch you to a different PPI
- •Methotrexate — omeprazole can increase methotrexate levels in the blood, raising the risk of toxicity
- •Diazepam (Valium) — omeprazole may increase diazepam levels and prolong its effects
- •Warfarin — omeprazole may enhance the blood-thinning effect of warfarin; INR monitoring is advised
- •Ketoconazole and itraconazole — omeprazole reduces stomach acid needed for absorption of these antifungals
- •Iron supplements — reduced stomach acid may decrease iron absorption
Pregnancy & Breastfeeding
Omeprazole should be used during pregnancy only if clearly needed and prescribed by a doctor. While animal studies have not shown direct harm, there is limited data in pregnant women. It is classified as Category C in pregnancy. Omeprazole passes into breast milk in small amounts. If you are breastfeeding, consult your doctor before taking omeprazole. For occasional heartburn during pregnancy, simpler antacids may be a safer first option.
NAFDAC-Registered Brands of Omeprazole in Nigeria
4 brands registered with NAFDAC as of 2026-02-01.
| Brand Name | Manufacturer | Strength | Form | NAFDAC Reg. No. |
|---|---|---|---|---|
| Losec | AstraZeneca | 20mg, 40mg | Capsule | A4-0345 |
| Omeprazole | Emzor | 20mg | Capsule | A4-5672 |
| Risek | Julphar | 20mg, 40mg | Capsule | B4-2345 |
| Omez | Dr. Reddy's | 20mg | Capsule | B4-3456 |
How to Verify Your Omeprazole is Genuine
- 1Check the NAFDAC registration number on the packaging — all genuine omeprazole products sold in Nigeria must carry a valid NAFDAC number
- 2Verify the NAFDAC number using the NAFDAC Green Book website or the NAFDAC mobile verification app available on Android and iOS
- 3Purchase from licensed pharmacies or registered patent medicine stores only — avoid buying from open markets, bus stops, or unregistered vendors
- 4Inspect the packaging for the manufacturer's details, batch number, manufacturing date, and expiry date — all should be clearly printed
- 5Genuine omeprazole capsules should have a consistent appearance — if the capsules look discoloured, damaged, or the contents appear different from usual, do not take them
- 6For major brands like Losec and Emzor Omeprazole, check for additional security features such as holographic seals or QR codes on the packaging
Omeprazole Price in Nigeria
Omeprazole prices in Nigeria typically range from ₦200 to ₦5,000 per pack, depending on the brand, strength, and where you buy it.
₦200 – ₦5,000
per pack
Prices vary by location and vendor. Last updated: 2026-02-01
Where to Buy
Purchase Omeprazole only from licensed pharmacies and verified distributors. Avoid buying medicines from unverified sources, roadside vendors, or unregistered market stalls.
Frequently Asked Questions
Sources
- •NAFDAC Greenbook — National Agency for Food and Drug Administration and Control registered products database
- •WHO Model List of Essential Medicines (23rd List, 2023)
- •British National Formulary (BNF)
- •Nigerian Standard Treatment Guidelines