Description

Simple

A medication used to improve the symptoms of heartburn, and to treat related conditions such as ulcers, tissue damage and infection with the bacteria called H. pylori.

Clinical

A proton pump inhibitor used to treat GERD associated conditions such as heartburn and gastric acid hypersecretion, and to promote healing of tissue damage and ulcers caused by gastric acid and H. pylori infection.

Overview

Originally approved by the FDA in 1989, omeprazole is a _proton-pump inhibitor_, used to treat gastric acid-related disorders. These disorders may include gastroesophageal reflux disease (GERD), peptic ulcer disease, and other diseases characterized by the oversecretion of gastric acid. This drug was the first clinical useful drug in its class, and its approval was followed by the formulation of many other proton pump inhibitor drugs [6]. Omeprazole is generally effective and well-tolerated, promoting its popular use in children and adults [FDA label].

Pharmacology

Indication

Omeprazole, according to the FDA label [FDA label] is a proton pump inhibitor (PPI) used for the following purposes:

• Treatment of active duodenal ulcer in adults

• Eradication of Helicobacter pylori to reduce the risk of duodenal ulcer
recurrence in adults

• Treatment of active benign... Read more

Pharmacodynamic

**Effects on gastric acid secretion**

This drug decreases gastric acid secretion [FDA label]. After oral administration, the onset of the antisecretory effect of omeprazole is usually achieved within one hour, with the maximum effect occurring by 2 hours after administration. The inhibitory effec... Read more

Mechanism of action

Hydrochloric acid (HCl) secretion into the gastric lumen is a process regulated mainly by the H(+)/K(+)-ATPase of the proton pump [ Read more

Absorption

Omeprazole delayed-release capsules contain an enteric-coated granule formulation of omeprazole (because omeprazole is acid-labile), so that absorption of omeprazole begins only after the granules exit the stomach [FDA label].

Absorption of omeprazole occurs rapidly, with peak plasma concentrati... Read more

Protein binding

Approximately 95% bound to human plasma proteins [FDA label].

Volume of distribution

Approximately 0.3 L/kg, corresponding to the volume of extracellular water [5].

Clearance

Healthy subject (delayed release capsule), total body clearance 500 - 600 mL/min [FDA label]Geriatric plasma clearance: 250 mL/min [FDA label]Hepatic impairment plasma clearance: 70 mL/min [FDA label]

Half life

0.5-1 hour (healthy subjects, delayed-release capsule) [FDA label]
Approximately 3 hours (hepatic impairment) [FDA label]

Route of elimination

After a single dose oral dose of a buffered solution of omeprazole, negligible (if any) amounts of unchanged drug were excreted in urine. Most of the dose (about 77%) was eliminated in urine as at least six different metabolites. Two metabolites were identified as _hydroxyomeprazole_ and the corresp... Read more

Toxicity

**Oral acute (LD50)**: 4000 mg/kg (mouse), 2210 mg/kg (rat) [MSDS].

**Overdose**

Symptoms of overdose include confusion, drowsiness, blurred vision, tachycardia, nausea, diaphoresis, flushing, headache, and dry mouth.

**Carcinogenesis and mutagenesis**

In 24-month studies in rats, a dos... Read more

Adverse Effects

Effect Regions Age Groups Incidences Evidence Type
Taste perversion US
  • Kind: experimental
    • Percent: 15
  • Clinical Trial
    Diarrhea US
  • Kind: experimental
    • Percent: 14
  • Clinical Trial
    Taste perversion US
  • Kind: experimental
    • Percent: 10
  • Clinical Trial
    Headache US
  • Kind: experimental
    • Percent: 7
  • Clinical Trial
    Headache US
  • Kind: experimental
    • Percent: 7%
  • Clinical Trial
    Headache US
  • Kind: experimental
    • Percent: 7%
  • Clinical Trial
    Headache US
  • Kind: experimental
    • Percent: 7%
  • Clinical Trial
    Abdominal Pain US
  • Kind: experimental
    • Percent: 5%
  • Clinical Trial
    Abdominal Pain US
  • Kind: experimental
    • Percent: 5%
  • Clinical Trial
    Abdominal Pain US
  • Kind: experimental
    • Percent: 5%
  • Clinical Trial
    Nausea US
  • Kind: experimental
    • Percent: 4%
  • Clinical Trial
    Nausea US
  • Kind: experimental
    • Percent: 4%
  • Clinical Trial
    Diarrhea US
  • Kind: experimental
    • Percent: 4%
  • Clinical Trial
    Nausea US
  • Kind: experimental
    • Percent: 4%
  • Clinical Trial
    Diarrhea US
  • Kind: experimental
    • Percent: 4%
  • Clinical Trial
    Diarrhea US
  • Kind: experimental
    • Percent: 4%
  • Clinical Trial
    Vomiting US
  • Kind: experimental
    • Percent: 3%
  • Clinical Trial
    Vomiting US
  • Kind: experimental
    • Percent: 3%
  • Clinical Trial
    Flatulence US
  • Kind: experimental
    • Percent: 3%
  • Clinical Trial
    Vomiting US
  • Kind: experimental
    • Percent: 3%
  • Clinical Trial
    Flatulence US
  • Kind: experimental
    • Percent: 3%
  • Clinical Trial
    Flatulence US
  • Kind: experimental
    • Percent: 3%
  • Clinical Trial
    Rhinitis US
  • Kind: experimental
    • Percent: 2
  • Clinical Trial
    Tongue discoloration US
  • Kind: experimental
    • Percent: 2
  • Clinical Trial
    Constipation US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Dizziness US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Constipation US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Constipation US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Rash US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Rash US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Dizziness US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Dizziness US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Rash US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Upper Respiratory Infection US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Acid Regurgitation US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Upper Respiratory Infection US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Upper Respiratory Infection US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Acid Regurgitation US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Acid Regurgitation US
  • Kind: experimental
    • Percent: 2%
  • Clinical Trial
    Flu syndrome US
  • Kind: experimental
    • Percent: 1
  • Clinical Trial
    Pharyngitis US
  • Kind: experimental
    • Percent: 1
  • Clinical Trial
    Asthenia US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Asthenia US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Asthenia US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Back Pain US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Cough US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Back Pain US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Back Pain US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Cough US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial
    Cough US
  • Kind: experimental
    • Percent: 1%
  • Clinical Trial

    Contraindications

    • Route:
      • Oral
    • Hypersensitivity:
      • true
      • Substituted benzimidazoles
    • Regions: US
    • Route:
      • Oral
    • Hypersensitivity:
      • true
    • Regions: US

    Food Interactions

    Take before a meal. Allow 30-60 minutes before a meal.