Omeprazol - Side Effects | Overdose | Use

This article was medically reviewed by M.Pharm, Marko Tanaskovic on August 12, 2018. To read more about an author, click here.

Omeprazol (Omeprazol) belongs to the family of medicines called proton pump inhibitors. It blocks proton pump in the stomach cells and stops acid secretion. This medication is one of the most commonly used medicines in the treatment of the following conditions:

  • Gastroesophageal reflux disease (GERD)
  • Gastric ulcer and duodenal ulcer
  • Gastric ulcer and duodenal ulcer caused by an infection from a bacteria called Helicobacter pylori
  • Zollinger-Ellison syndrome


Omeprazol should be avoided in the following conditions:

  • If you are allergic to Omeprazol or other similar medicines, such as: esomeprazole, pantoprazole and others. Symptoms of an allergy include: itching of the skin, redness of the skin, skin rash, swelling of the lips and difficulty breathing.

Omeprazol should be used only with extra precautions in the following conditions:

  • Liver damage.
  • Low magnesium levels in the blood (hypomagnesaemia)
  • Tell your doctor that you are using Omeprazol, if you are planning surgery
  • Bone diseases (e.g, osteoporosis), because long-term use of this medicine increases the risk of bone fracture, especially in patients above  the age of 60.

It is necessary to exclude the possibility of digestive-tract cancers, before you start taking Omeprazol. Omeprazol can mask the stomach cancer symptoms and make it more difficult to detect stomach cancer. Contact your doctor immediately if you are experiencing symptoms, such as: vomiting blood, blood in the stool (black stool), pain while swallowing.

It takes at least 3-4 days before you feel improvement.

Use of Omeprazol during pregnancy and breastfeeding

Omeprazol should be used during pregnancy only if the benefit to the mother outweighs the risk to the child.

It passes into breast milk and may harm your baby. Avoid breastfeeding while using Omeprazol.

How to use

Omperazol should be taken in the morning, after you get up.

It should be taken with a glass of lukewarm water.

Usual initial dose of Omeprazol is 20 mg once a day. The dose may be increased up to 40 mg per day (20 mg in the morning and 20 mg in the evening).

Usual dose in the treatment of Zollinger-Ellison syndrome is 60 mg per day.

Your doctor will tell you for how long you need to take Omeprazol.


Symptoms of an overdose include: flushing, headache, blurred vision, confusion, dry mouth, nausea and abnormal heart beats. If you take more Omeprazol capsules than recommended by your doctor, contact your doctor immediately.

Use with other medicines (Interactions)

Omeprazol should be avoided in combination with the following medications:

  • Medicines used in the treatment of fungal infections, such as: fluconazole, itraconazole, ketoconazole and others.
  • Medicines used in the treatment of viral infections (HIV-AIDS), such as: nelfinavir, saquinavir, and others.
  • Antibiotics, such as: ampicillin, amoxicillin, rifampicin, and others.
  • Medicines used to treat breast cancer, such as: methotrexate.
  • Phenytoin, used to treat epilepsy.
  • Medicatons used to treat blood clots (anticoagulants), such as: warfarin (Farin) and acenocoumarol (Sintrom, Sinkum 4).
  • Antiplatelet medicines, such as: clopidogrel
  • Diazepam (Bensedin), used to treat insomnia.
  • Digoxin, used to treat heart failure.
  • St. John's Wort.

Tell your doctor about all medications and herbal medicines you are taking.

Side effects

Omeprazol may cause following side effects:

  • Nausea
  • Vomiting
  • Bloating
  • Abdominal pain
  • Diarrhea
  • Constipation
  • Headache
  • Flushing
  • Insomnia
  • Dizziness
  • Muscle pain
  • Kidney damage (difficulty urinating)
  • Seizures
  • Tachycardia (rapid heartbeat)
  • Low levels of magnesium in the blood (hypomagnesaemia)
  • Tremor
  • Low white blood cell count
  • Anemia
  • Vitamin B12 deficiency
  • Dry mouth
  • Hair loss (alopecia)
  • Allergy and others.

Tell your doctor if you are experiencing any side effects.

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.

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