What is Omeprazole

Omeprazole 20 Mg capsules

Omeprazole | Side Effects, Dosage, Uses & More

Is Omeprazole an organic or inorganic compound?

Omeprazole is a synthetic organic compound.

Omeprazole and Omeprazole magnesium molecular weight

Omeprazole empirical formula is C17H19N3O3S, with a molecular weight of 345.42.

Omeprazole is generally manufactured as a Magnesium salt(2:1). The empirical formula for Omeprazole magnesium is (C17H18N3O3S)2 Mg and the molecular weight is 713.12. Omeprazole is a racemic mixture(50:50 of S-Omeprazole and R-Omeprazole).

Chemical characteristics of Omeprazole and Omeprazole magnesium

Omeprazole is a white to off-white crystalline powder. The stability of Omeprazole is directly related to the acidity of the medium; it is rapidly degraded in acid media. Omeprazole magnesium is a white to off white powder. The time that take to eliminate half of Omerpazole magnesium from our blood is highly pH dependent.

What ’s the story behind the Omeprazole?

Omeprazole was the first Proton Pump Inhibitor approved worldwide. It was synthesized first in 1979, by Astra AB(now AstraZeneca). It was approved in USA in 1989. The molecular predecessor of Omeprazole, Timoprazole was developed in 1975(4).

Omeprazole is the only Proton Pump Inhibitor included in WHO’s list of Essential Medicines 2015(5).

Omerazole brand names

1. Prilosec is the brand name commercialize in USA as Omeprazole prescription medication. Prilosec is available in 10 mg, 20 mg and 40 mg delayed-release capsule. It is also available as an delayed- release oral suspension in sachet of 2.5 or 10 mg of Omeprazole. Omeprazole prescription is also available in generic brands.

2. Prilosec OTC is the brand commercialized in USA as Omeprazole OTC. Prilosec OTC is available as a 20 mg delayed-release tablet. Omeprazole OTC is available in generic brands too.

3. Triple therapy, it is available in a pack of 10 daily administration cards. Each card contains treatment for 24 hours, split in morning and evening dosing. Each card contains: two omeprazole delayed-release capsules, USP, 20 mg, two clarithromycin tablets, USP, 500 mg and four amoxicillin capsules, USP, 500 mg

4. Yosprala Delayed-Release Tablets, it is available as 81 mg delayed-release aspirin/40 mg immediate-release omeprazole  or 325 mg delayed-release aspirin/40 mg immediate-release omeprazole

5. Zegerid contains omeprazole and sodium bicarbonate. Zegerid is available as powder for oral suspension(omeprazole 20 mg or 40 mg and sodium bicarbonate 1680 mg) and capsules(Omeprazole 20 mg or 40 mg and sodium bicarbonate 1100 mg) for oral use. This medication has generic brand too.

6. Zegerid OTC is available as a capsule containing Omeprazole 20MG and Sodium Bicarbonate 1100 MG. Zegerid OTC is also available as a powder for oral solution containing Omeprazole 20 mg and Sodium Bicarbonate 1680 mg.

What Omeprazole does in your body?

Omeprazole reduces the amount of acid in your stomach.

What is Omeprazole for?

omeprazole delayed release capsules 40 mg
Omeprazole delayed release capsules 40 mg

Your doctor can prescribe Omeprazole for treating active ulcer in the duodenum of adults. It is regularly prescribed as a 4 week treatment. However, some patients may need another 4 weeks treatment of Omeprazole. The duodenum is the area where food passes when it leaves the stomach.

Omeprazole is prescribed in combination with antibiotics clarithromycin and amoxicillin, for treating patients with H. pylori infection in adults. The infection needs to be treated to prevent the ulcers from coming back.

Adults can get prescribed Omeprazole for not-cancerous active ulcer in the stomach. The short term treatment lasts from 4 to 8 weeks.

Children and adults may need up to 4 weeks of Omeprazole to treat heartburn. Heartburn happens when acid in your stomach backs up into the tube (esophagus) that connects your mouth to your stomach. This may cause a burning feeling in your chest or throat, sour taste, or burping.

Omeprazole is indicated for children and adults diagnosed with erosive esophagitis. Initial recommended treatment with Omeprazole is for 4 to 8 weeks. In some patients, the prescriber could recommend another 4 weeks of treatment, or 8 additional weeks of treatment in case of recurrent esophagitis.

Children and adults may need up to 12 weeks of Omeprazole to maintain healing of erosive esophagitis.

Omeprazole is prescribed for adults with excessive production of acid in the stomach like Zollinger-Ellison syndrome, multiple endocrine adenomas and systemic mastocytosis.

How Omeprazole reduces acidity in your stomach?

First of all, Omeprazole get into your body. Then, if stomach acidity is very low due to the presence of food, Omeprazole goes to parietal cells(known to secrete gastric acid) in the stomach.

Once in the stomach, Omeprazole is activated and binds covalently to H+, K+- ATPase enzymatic system. This binding prevents acid secretion in the stomach.

How is Omeprazole absorbed?

Omeprazole can be taken by mouth. Most of the oral Omeprazole is formulated with an acid-resistant coating that does not dissolve until pH ~5.0. The acidresistant coating allows the Omeprazole to pass through the stomach safely, and once in a the duodenum, Omeprazole can be absorbed.

Neither food nor antacids have any effect on the absorption of Omeprazole. Omeprazole can be administered intravenously too.

Does Omeprazole undergo first-pass metabolism?

After oral or intravenous administration, Omeprazole goes through our liver and get transformed before it is released into our blood. This process in the liver is called first-pass metabolism and it happens to several medications.

Mainly in the liver, Omeprazole get processed by 2 enzymes CYP 2C19 and CYP 4A5. The liver enzymes leaves 35 % of Omeprazole unchanged and the rest gets transformed into inactive chemicals that get eliminated. After a week of treatment the liver enzymes release 43% of Omeprazole unchanged.

Unfortunately, CYP 2C19 capacity to process chemicals varies from person to person. Approximately 3% of the Caucasian people and 15-20% of Asian populations lack a functional CYP 2C19 enzyme and are called poor metabolizers. Poor metabolizers get too much unchanged Omeprazole in their blood stream.

Some chemicals can affect the performance of CYP enzymes too, including the same Omeprazole. Omeprazole reduces the activity of CYP 2C19 after a single dose, and reduces even more the performance of CYP 2C19 after continues use.

Recommended doses are calculated based on general population characteristics, what leave poor metabolizers at risk to get to much of a medication, if they are not aware of their genetic inhabitability to process some chemicals.

Too much Omeprazole is not an issue for poor metabolizers because Omeprazole is safe even at higher doses. However, patients could experience excessive side effects.
Omeprazole can reach our blood stream as soon as 30 minutes after an oral dose.

The maximum levels of Omeprazole in blood are after 2 hours of taking an oral dose. After 1 hour in our blood, 50% of Omeprazole is already eliminated. It binds to blood proteins in 95%.

What Omeprazole does in parietal cells?

Omeprazole has high affinity for parietal cells in the stomach, because Omeprazole is a weak base with high affinity for areas where ph is below 4. This high levels of acidity only get reached in our stomach after eating. Omeprazole concentration in the parietal cell is 1000-fold compared to blood after food.

Omeprazole gets rapidly activated after 2 transformations(protonations). Once Omeprazole is active, it binds to Cysteine 813 and 892 in the proton pump system by disulfide covalent bond. The bond to Cysteine 813 impels the H,KATPase system to release acid. This bond is not irreversible.

H,K-ATPase system is also known as Proton(acid) Pump enzymatic system and medications like Omeprazole are known as Proton Pump Inhibitors or PPI.
A proton pump system last about 54 h in humans and 20% new pumps are replaced in our bodies after a 24-h period.

Omeprazole dosage

How much Omeprazole I should take?

Omeprazole for active duodenal ulcer in adults: 20 mg daily for 4 weeks. Patient may need another 4 weeks of treatment.

Omeprazole for treatment of H. pylori in adults: Triple Therapy (Omeprazole/ clarithromycin/amoxicillin) The recommended adult oral regimen is Omeprazole 20 mg plus clarithromycin 500 mg plus amoxicillin 1000 mg each given twice daily for 10 days. Give another 18 days of Omeprazole 20 mg daily after triple therapy, in patients with an ulcer.

Omeprazole for alternative treatment of H. pylori for adults: Dual Therapy (Omeprazole/clarithromycin)

The recommended adult oral regimen is Omeprazole 40 mg once daily plus clarithromycin 500 mg three times daily for 14 days. In patients with an ulcer present at the time of initiation of therapy, an additional 14 days of Omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief.

Omeprazole for active benign gastric ulcer in adults: 40 mg once daily for 4 to 8 weeks. – Omeprazole for heartburn in adults: 20 mg daily for up to 4 weeks.

Omeprazole for heartburn in adults with erosive esophagitis: 20 mg for 4 o 8 weeks

Omeprazole for maintenance of healing of erosive esophagitis in adults: 20 mg daily for no more than 12 weeks

Omeprazole for medical conditions that causes excessive production of gastric acid in adults: initial dose is 60 mg daily. Dose is increased case-by-case up to 120 mg three times a day. Any dose greater than 80 mg should be split during the day. Patients with excessive production of acid have been on Omeprazole for over 5 years successfully.

Use of Omeprazole in Children

It is safe to prescribe Omeprazole in infants from 1 month to 1 year old for erosive esophagitis. It is also safe and well studied the use of Omeprazole in children from 1 to 16 years old for heartburn, erosive esophagitis and maintenance of healing of erosive esophagitis. Infants and children on Omeprazole are more prompt to: ear infections, fever and accidental injuries.  Omeprazole is not recommended in patients less than 1 month of ag

What is the dose of Omeprazole in children?

Dose of Omeprazole in children are determined by the weight of the child.

  • 3 to less than 5 kg: 2.5 mg daily
  • 5 to less than 10 kg: 5 mg daily
  • 10 kg and greater: 10 mg daily
  • 20 kg and greater: 20 mg daily
  • Children (1-16 years old) with heartburn need one dose daily for up to 4 weeks.
  • Children (1-16 years old) with erosive esophagitis need one dose daily for 4-8 weeks.
  • Infants (1month-1year old) with erosive esophagitis need one dose daily for ups to 6 weeks.
  • Children (1-16 years old) with maintenance treatment of erosive esophagitis need one dose daily. Studies has not been extended for more than 12 months.

Use of Omeprazole in individuals 65 years old or older

Omeprazole has no differences in safety and effectiveness between elderly and younger subjects. It is known that elimination of Omeprazole in seniors is slower and duration of medication in blood is longer than in younger persons. Regardless, there is no need of dosage adjustment in elderly.

Use of Omeprazole in patients with liver medical conditions

In patients with a liver not fully functional, dosage of Omeprazole should be 10 mg daily for maintenance of healing of Erosive Esophagitis.

Use of Omeprazole in Asian population

Asians on Omeprazole have four-fold higher exposure than Caucasians. That’s why dose reduction to 10 mg daily is recommended in the maintenance of healing of erosive esophagitis in Asians.

Omeprazole side effects and how to deal with them

Dealing with side effects has a lot of common sense in it.

It is normal that you experience mild, transient discomfort when you start taking a medication. You could notice minor side effects linked to your body dealing with a new chemical like Omeprazole, in this case the reduction in acidity of your stomach.

However, if this discomfort persist after a few days, or it get worse at any time, you must contact your doctor to reassess your Omeprazole therapy. If you suddenly star to experience a life-threatening reaction like shortness of breath you should go to emergency immediately.

Most common side effects of Omeprazole reported in adults:

  1. Headaches: like most of the medications it can cause headaches.
  2. Abdominal pain, nausea, diarrhea, vomiting, flatulence, constipation: any change in our stomach acidity will cause temporary discomfort
  3. Chest infection, cough: should be transient, otherwise doctor need to reassess Omeprazole therapy
  4. Dizziness: transient and very common with a new treatment
  5. Rash: if it doesn’t go away after a few days or get worse, check with your doctor.
  6.  Lack of energy: should be temporary, otherwise call your doctor
  7. Back pain: if it doesn’t go away in a few days, call your doctor
  8. Regurgitation: if it doesn’t go away in a few days contact your doctor

Most common side effect of Omeprazole in children:

In addition to side effects reported in adults’ side effects children could experience:

  1. More frequently reported cough and upper respiratory infections
  2. Fever
  3. Accidental injuries

These side effects in children require doctor assessment. Do not overlook at them.

What could be a serious allergic reactions with Omeprazole?

  1. rash
  2. face swelling
  3. throat tightness
  4. difficulty breathing

Tell your doctor if you have any side effect that bothers you or that does not go away.

After years of use of Omeprazole, other side effects have been associated to taking Omeprazole.

Side effects listed below may or may not be linked to the use of the medication. Regardless, you should contact your doctor when you experience any of them. If at any time you experience a life threatening side effect you should go to emergency immediately.

  1. Anaphylaxis, angioedema, bronchospasm, interstitial nephritis, urticaria, fever, pain, fatigue, malaise
  2. Chest pain or angina, low or high heart rate, palpitations, elevated blood pressure, swollen arms and/or legs
  3. Gynecomastia (enlargement of man’s breast)
  4.  Pancreatitis, anorexia, irritable colon, change in color of the stools, fungal infection of esophagus, atrophy of the mucose of the tongue, stomatitis, abdominal swelling, dry mouth
  5. Liver failure, liver necrosis, hepatic encephalopathy, cholestatic disease, mixed hepatitis, jaundice, and elevations of liver function tests
  6. Clostridium difficile associated diarrhea. Omeprazole may increase your risk of getting severe diarrhea. Call your doctor right away if you have watery stool, stomach pain, and fever that does not go away.
  7. Low sugar levels, low magnesium, with or without low calcium and/or low potassium, low sodium, weight gain
  8. Muscle weakness, muscle pain, muscle cramps, joint pain, leg pain, bone fracture
  9.  Bone fractures. People who take multiple daily doses of Omeprazole for a long period of time (a year or longer) may have an increased risk of fractures of the hip, wrist, or spine.
  10. Depression, agitation, aggression, hallucinations, confusion, insomnia, nervousness, apathy, somnolence, anxiety, and dream abnormalities; tremors, paresthesia; vertigo
  11. Nosebleed, pharyngeal pain
  12. .Some serious and generalized skin reactions have been reported, including toxic epidermal necrolysis (some fatal), Stevens-Johnson syndrome, and erythema multiforme. Some other side effects have been describe by patients using Omeprazole like sensitivity to light, urticaria, rash, skin inflammation, itchiness; petechiae; purpura; lost of hair; dry skin; excessive perspiration
  13. Tinnitus(hearing a sound when no external sound is present), alteration of taste
  14. Eye issues like optic atrophy, anterior ischemic optic neuropathy, optic neuritis, dry eye syndrome, ocular irritation, blurred vision, double vision
  15. .Interstitial nephritis, blood in urine, protein in urine, elevated serum creatinine, microscopic pyuria, urinary tract infection, sugar in urine, urinary frequency, testicular pain
  16. .Blood elements can be altered by Omeprazole. Patient on Omeprazole has been diagnosed with: Agranulocytosis (some fatal), hemolytic anemia, pancytopenia, neutropenia, anemia, thrombocytopenia, leukopenia, leucocytosis
  17. Vitamin B-12 deficiency: Omeprazole reduces the amount of acid in your stomach that is needed to absorb vitamin B-12 properly. Talk to your doctor
    about the possibility of vitamin B-12 deficiency if you have been on Omeprazole for more than 3 years.
  18. Low magnesium levels in your body. This problem can be serious. Low magnesium can happen in some people who take a proton pump inhibitor (PPI) medicine, like Omeprazole. If low magnesium levels happen, it is usually after a year of treatment. You may or may not have symptoms of low magnesium.

Tell your doctor right away if you develop any of these symptoms of low magnesium:  

  • seizures
  • dizziness
  • abnormal or fast heart beat
  • jitteriness
  • jerking movements or shaking (tremors)
  • muscle weakness
  • spasms of the hands and feet
  • cramps or muscle aches
  • spasm of the voice box

Warnings and precautions while using Omeprazole

  • Patients with gastric malignancies can respond to Omeprazole treatment. However, controlling of stomach acidity does not guarantee improvement in gastric malignancies.
  • Atrophic gastritis has been noted occasionally with long-term therapy.
  • Acute interstitial nephritis has been observed in patients taking Omeprazole and other PPIs. It is unknown the way that Omeprazole can trigger the interstitial nephritis, but Omeprazole must be discontinued immediately .
  • Vitamin B-12 deficiency has been identified in patients taking Omeprazole for longer than 3 years. This is directly linked to poor absorption of vitamin B-12 in a stomach with reduced acidity like in patients taking Omeprazole.
  • Severe diarrhea associated to Clostridium difficile is more likely to happen to patients taking Omeprazole. Patients should be aware of this potential severe reaction, and seek medical attention in the event they start to develop severe diarrhea.
  • Patients on PPIs, including Omeprazole have increased chances of bone fractures of hip, wrist or spine associated to Osteoporosis.
  • Low magnesium can be developed in patients taking Omeprazole and other PPIs.
  • While on Omeprazole, avoid using Clopidogrel, St. John’s Wort, Rifampin and high doses of Methotrexate.
  • Stop Omeprazole 14 days prior investigations for neuroendocrine tumors(CgA levels).

Who should not take Omeprazole?

  • persons allergic to omeprazole or any of the non medical ingredients in it.
  • persons allergic to any other Proton Pump Inhibitor (PPI) medicine.
  • persons taking a medicine that contains rilpivirine used to treat HIV-1.
  • persons allergic to clarithromycin or amoxicillin when taking triple therapy.

What should I tell my doctor before taking Omeprazole?

  1.  that you have low magnesium levels in your blood
  2.  that you have liver problems
  3.  that you have any other medical conditions
  4.  that you are pregnant or plan to become pregnant.
  5.  that you are breastfeeding or plan to breastfeed.
  6. Tell your doctor about all of the medicines you take including prescription and over-the-counter medicines, vitamins and herbal supplements.

Omeprazole effect on serum gastrin and CgA levels

When a patient starts taking Omeprazole, the levels of serum gastrin increased during the first 1 to 2 weeks of daily doses of Omeprazole, in addition to the reduction in acid secretion. Gastrin values returned to pretreatment levels, usually within 1 to 2 weeks after discontinuation of therapy. Increased gastrin
causes serum increased Chromogranin A (CgA) levels and enterochromaffin-like cell hyperplasia.

Patients on Omeprazole can have increased CgA levels that may cause false positive results in diagnostic investigations for neuroendocrine tumors

Patients on Omeprazole have Enterochromaffin-like (ECL) Cell Effects increases in direct correlation to duration of treatment; however, no case of ECL cell carcinoids, dysplasia, or neoplasia has been found in these patients. The studies where not run long enough to rule out the possible influence of long-term administration of omeprazole on the development of any premalignant or malignant conditions.

Other influences of Omeprazole in our body

According to studies, Omeprazole does not affect the Central Nervous System, Cardiovascular system or respiratory system.

Omeprazole, given at therapeutic doses, had no effect on thyroid function, carbohydrate metabolism, or circulating levels of parathyroid hormone, cortisol, estradiol, testosterone, prolactin, cholecystokinin or secretin.

After a single dose of omeprazole, there are no effect on gastric emptying of the solid and liquid components of a meal. In healthy persons, a single intravenous dose of omeprazole had no effect on intrinsic factor secretion.

Omeprazole that was administered for 14 days in healthy subjects produced a significant increase in the intragastric concentrations of viable bacteria. The pattern of the bacterial species was unchanged from that commonly found in saliva. All changes resolved within three days of stopping treatment.

Omeprazole has no clinically significant impact on Barrett’s mucosa. Although neosquamous epithelium developed during antisecretory therapy, complete elimination of Barrett’s mucosa was not achieved.

While on Omeprazole no significant development of dysplasia in Barrett’s mucosa was observed and no patient developed esophageal carcinoma during treatment. No significant differences between treatment groups were observed in development of ECL cell hyperplasia, corpus atrophic gastritis, corpus intestinal metaplasia, or colon polyps exceeding 3 mm in diameter.

Omeprazole carcinogenesis studies

The possibility of Omeprazole causing cancer has been studied in animals. Omeprazole produced Enterochromaffin-like (ECL) Cells in direct correlation to dose of Omeprazole. Animals were treated with Omeprazole for 1 year and observed for another year without medication. Studies concluded that growing of tissue in response to a stimulus is observed, but carcinoids were not seen.

Omeprazole Fertility studies

Omeprazole at oral doses was found to have no effect on fertility and reproductive performance.

How to store Omeprazole prescription?

Omeprazole delayed-release capsules should be kept in a tight container protected from light and moisture. Store between 59°F and 86°F.  Omeprazole for delayed-release oral suspension should be kept at 77°F; excursions permitted to 59 – 86°F.

Omeprazole FAQ

  1. What happens if I overdose on omeprazole?
  2. How to take omeprazole correctly?
  3. How long does omeprazole take to work for heartburn, acid reflux (GERD), ulcer?
  4. How long does it take for omeprazole to get out of your system?

Omeprazole interactions with other medicines

  1. Can you take omeprazole with coumadin?
  2. Can I take omeprazole with low doese of methotrexate?
  3. Can I take omeprazole with clopidogrel?
  4. Can I take omeprazole with citalopram?
  5. Can I take omeprazole with cilostazol?
  6. Can I take omeprazole with phenytoin?
  7. Can I take omeprazole when pregnant or nursing
  8. Omeprazole interactions with Rilpivirine, Indinavir, Atazanavir Saquinavir and Nelfinavir
  9. Can I take omeprazole with diazepam?