Omeprazole: An Overview of Pharmacology and Applications

1. General Properties:

• Drug Class: Proton pump inhibitor (PPI)
• Chemical Structure: 2-sulfinylmethyl pyridin derivative of benzimidazole
• Physical Form: White crystalline powder
• Solubility:
  • Water: Sparingly soluble
  • Alcohol: Soluble
• Racemic Mixture: Omeprazole has one chiral center and therefore exists as a racemic mixture.
• Stability: Stable in alkaline environments, unstable in acidic environments.
• Properties:
  • Basicity: Omeprazole is basic due to the pyridine ring, not imidazole.
  • Reaction with Common Reagents: It reacts with common alkaloid reagents (like Mayer’s reagent, Dragendorff’s reagent) due to the presence of the pyridine ring.
  • Color Complex Formation with Metals: Forms colored complexes with some metals due to its acidic nature.

2. Quantification:

• Methods: Acid-base titration, moisture content determination, UV spectrophotometry can be used.

3. Pharmacokinetics:

• Absorption: Rapidly absorbed after oral administration, with a bioavailability of around 70%.
• Distribution: Extensively bound to plasma proteins (around 95%).
• Elimination Half-Life: Omeprazole has a relatively long elimination half-life, not short. This is due to the irreversible and prolonged nature of proton pump inhibition.
• Mechanism of Action:
  • Omeprazole is an irreversible inhibitor of the H+/K+/ATPase pump.
  • Mechanism of Action:
    • Omeprazole is absorbed into gastric parietal cells.
    • In the acidic environment of the stomach, Omeprazole is activated to its sulphenic acid and sulphenamic acid forms.
    • These activated forms bind reversibly to the sulfhydryl group of the H+/K+/ATPase pump, inhibiting its activity.
    • This results in a decrease in gastric acid secretion.

4. Clinical Applications:

• Indications:
  • Treatment of duodenal ulcers that have not responded to H2 receptor antagonists.
  • Zollinger-Ellison syndrome.
  • Chronic gastroesophageal reflux disease (GERD).
• Time of Administration: Taken before meals, preferably one hour before a meal, on an empty stomach.
• Formulation: Usually formulated as enteric-coated capsules to protect the drug from degradation by gastric acid.

5. Contraindications:

• Malignant gastric ulcers.
• Hypersensitivity to omeprazole or other PPIs.
• Pregnancy and lactation (use with caution).

6. Drug Interactions:

• Omeprazole can inhibit the metabolism of several drugs, including diazepam, phenytoin, warfarin, nifedipine.
• Note: Careful monitoring of drug levels is needed when using omeprazole concurrently with these medications.

7. Precautions:

• Hepatic Impairment: Dosage reduction may be necessary for patients with liver dysfunction.
• Renal Impairment: Monitor renal function.
• Elderly Patients: Closely monitor for adverse effects.

Note:

• This article is for informational purposes only and should not be considered as medical advice.
• Consult a physician before using any medication.
• Information about drugs may change over time; refer to the most up-to-date information from reliable sources.

Additional Information:

• Omeprazole is a prescription medication.
• Omeprazole may cause some side effects such as nausea, diarrhea, constipation, headache, dizziness.

Important Note:

• This article provides basic information about omeprazole.
• A healthcare professional will make the most appropriate decision regarding the use of this medication for each specific case.
• In addition to the information in this article, consult the manufacturer and a healthcare professional for a comprehensive understanding of omeprazole and its safe and effective use.