Omeprazole is widely applied to treat evidences of gastroesophageal reflux disease (GERD) and other conditions caused by excess acidic formulations in the stomach.
Therapeutic indications used Omeprazole
Treatment of duodenal ulcers
• Prevention of relapse of duodenal ulcers
• Treatment of gastric ulcers
• Prevention of relapse of gastric ulcers
• In combination with appropriate antibiotics, Helicobacter pylori (H. pylori) eradication in peptic ulcer disease
• Treatment of NSAID-associated gastric and duodenal ulcers
• Prevention of NSAID-associated gastric and duodenal ulcers in patients at risk
• Treatment of reflux oesophagitis
• Long-term management of patients with healed reflux oesophagitis
• Treatment of symptomatic gastro-oesophageal reflux disease
• Treatment of Zollinger-Ellison syndrome
Pharmacodynamics
Omeprazole is a compound that inhibits gastric acid secretion and is indicated in the treatment of gastroesophageal reflux disease (GERD), the healing of erosive esophagitis, and H. pylori eradication to reduce the risk of duodenal ulcer recurrence. Omeprazole belongs to a new class of antisecretory compounds, the substituted benzimidazoles, that do not exhibit anticholinergic or H2 histamine antagonistic properties, but that suppress gastric acid secretion by specific inhibition of the H+/K+ ATPase at the secretory surface of the gastric parietal cell. As a result, it inhibits acid secretion into the gastric lumen. This effect is dose-related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus.
Mechanism of action
Omeprazole is a proton pump inhibitor that suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase in the gastric parietal cell. By acting specifically on the proton pump, omeprazole blocks the final step in acid production, thus reducing gastric acidity.
half life
0.5-1 hour
The absorption of certain drugs may be affected by stomach acidity. Therefore, omeprazole as well as other PPIs reduce the absorption and concentration in blood of ketoconazole (Nizoral) and increase the absorption and concentration in blood of digoxin (Lanoxin). This may reduce the effectiveness of ketoconazole or increase digoxin toxicity.
Through unknown mechanisms, omeprazole may increase blood levels of saquinavir and reduce blood levels of nelfinavir and atazanavir, drugs that are used for treating patients with infection caused by the human immunodeficiency virus (HIV). Accordingly, the dose of saquinavir may need to be reduced to avoid toxicity, and the doses of nelfinavir and atazanavir may need to be increased to maintain efficacy.
Pregnancy and lactation
Results from three prospective epidemiological studies (more than 1000 exposed outcomes) indicate no adverse effects of omeprazole on pregnancy or on the health of the foetus/newborn child. Omeprazole can be used during pregnancy.
Omeprazole is excreted in breast milk but is not likely to influence the child when therapeutic doses are used.
Drug Interactions - Because omeprazole can inhibit the cytochrome P-450 enzyme system, omeprazole may decrease the hepatic clearance of diazepam, phenytoin or warfarin, thereby enhancing their effects and causing potential toxicity. Additional monitoring and dosage adjustments may be required. Because omeprazole can increase gastric pH, drugs that require low gastric pH for optimal absorption (e.g., ketoconazole, ampicillin esters or iron salts) may have their absorption reduced. Although omeprazole causes bone marrow depression only rarely in humans, use with other drugs that cause bone marrow depression may lead to additive hematologic abnormalities.
Omeprazole side effects.
- back pain;
- blurred vision;
- burning or tingling of the lips, tongue, hands, or feet;
- confusion;
- constipation;
- cough;
- diarrhea;
- difficulty breathing or swallowing;
- dizziness;
- drowsiness;
- dry mouth;
- fast or pounding heartbeat;
- flushing (feeling of warmth);
- headache;
- hives;
- hoarseness;
- itching;
- muscle spasms, tightening, aching, or cramping;
- nausea;
- rash;
- seizures;
- stomach pain;
- sweating;
- swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs;
- vomiting;
Omeprazole Dosing Information
Usual Adult Omeprazole Dose for Duodenal Ulcer:
20 mg orally once a day before a meal. Most patients heal within 4 to 8 weeks.
Usual Adult Omeprazole Dose for Helicobacter pylori Infection:
Dual therapy: omeprazole 40 mg orally once a day in the morning plus clarithromycin 500 mg orally 3 times a day on days 1 to 14. Beginning on day 15, omeprazole 20 mg orally once a day in the morning on days 15 to 28.
Triple therapy: omeprazole 20 mg plus clarithromycin 500 mg plus amoxicillin 1000 mg all given orally twice a day for 10 days. If an ulcer is present at the initiation of therapy, continue omeprazole 20 mg orally once a day for an additional 18 days.
Study (n=294) - Canadian Adult Dyspepsia Empiric Treatment-Helicobacter pylori positive (CADET-Hp): omeprazole 20 mg, metronidazole 500 mg, and clarithromycin 500 mg, twice daily for 7 days.
Usual Adult Omeprazole Dose for Gastric Ulcer:
40 mg orally once a day before a meal for 4 to 8 weeks.
Usual Adult Omeprazole Dose for Erosive Esophagitis:
20 mg orally once a day before a meal. This dosage may be increased to 40 mg per day based on desired clinical response and patient tolerance. Studies have been completed up to 12 months for maintenance therapy of erosive esophagitis.
Usual Adult Dose for Zollinger-Ellison Syndrome:
Initial: 60 mg orally once a day. Dosage should be individualized to patient's needs.
Maintenance: doses up to 120 mg 3 times a day have been administered. Daily doses greater than 80 mg should be divided.
Usual Adult Dose for Gastroesophageal Reflux Disease:
Initial: 20 mg orally once a day before a meal for 4 to 8 weeks. This dosage may be increased to 40 mg per day if needed.
Maintenance: long-term treatment with doses of 10 to 20 mg per day may be required for maintenance therapy of refractory disease and appears to be safe.
Usual Adult Dose for Multiple Endocrine Adenomas:
Initial: 60 mg orally once a day before a meal. This dosage may be titrated based on desired clinical response and patient tolerance.
Maintenance: doses up to 120 mg 3 times a day have been administered. Daily doses greater than 80 mg should be divided.
Usual Adult Dose for Systemic Mastocytosis:
Initial: 60 mg orally once a day before a meal. This dosage may be titrated based on desired clinical response and patient tolerance.
Maintenance: doses up to 120 mg 3 times a day have been administered. Daily doses greater than 80 mg should be divided.
Usual Adult Dose for Dyspepsia:
Prevention of frequent heartburn: 20 mg orally once daily, before a meal, for 14 days.
Usual Pediatric Omeprazole Dose for Gastroesophageal Reflux Disease:
>2 years
<20 kg: 10 mg once a day.
>=20 kg: 20 mg once a day
Studies:
>1 year: 0.7 to 3.5 mg/kg/day, given in 2 divided doses, not to exceed 80 mg daily.
Study (n=115)
<1 year: 1 to 1.5 mg/kg once daily for 56 days. Omeprazole was administered orally as a 2 mg/mL bicarbonate suspension.
Usual Pediatric Omeprazole Dose for Erosive Esophagitis:
>1 years: 0.7 to 3.5 mg/kg/day (maximum 80 mg/day), for 3 months. Dosage increments of 0.7 mg/kg/day to achieve stomach pH of <4.
Therapeutic indications used Omeprazole
Treatment of duodenal ulcers
• Prevention of relapse of duodenal ulcers
• Treatment of gastric ulcers
• Prevention of relapse of gastric ulcers
• In combination with appropriate antibiotics, Helicobacter pylori (H. pylori) eradication in peptic ulcer disease
• Treatment of NSAID-associated gastric and duodenal ulcers
• Prevention of NSAID-associated gastric and duodenal ulcers in patients at risk
• Treatment of reflux oesophagitis
• Long-term management of patients with healed reflux oesophagitis
• Treatment of symptomatic gastro-oesophageal reflux disease
• Treatment of Zollinger-Ellison syndrome
Pharmacodynamics
Omeprazole is a compound that inhibits gastric acid secretion and is indicated in the treatment of gastroesophageal reflux disease (GERD), the healing of erosive esophagitis, and H. pylori eradication to reduce the risk of duodenal ulcer recurrence. Omeprazole belongs to a new class of antisecretory compounds, the substituted benzimidazoles, that do not exhibit anticholinergic or H2 histamine antagonistic properties, but that suppress gastric acid secretion by specific inhibition of the H+/K+ ATPase at the secretory surface of the gastric parietal cell. As a result, it inhibits acid secretion into the gastric lumen. This effect is dose-related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus.
Mechanism of action
Omeprazole is a proton pump inhibitor that suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase in the gastric parietal cell. By acting specifically on the proton pump, omeprazole blocks the final step in acid production, thus reducing gastric acidity.
half life
0.5-1 hour
The absorption of certain drugs may be affected by stomach acidity. Therefore, omeprazole as well as other PPIs reduce the absorption and concentration in blood of ketoconazole (Nizoral) and increase the absorption and concentration in blood of digoxin (Lanoxin). This may reduce the effectiveness of ketoconazole or increase digoxin toxicity.
Through unknown mechanisms, omeprazole may increase blood levels of saquinavir and reduce blood levels of nelfinavir and atazanavir, drugs that are used for treating patients with infection caused by the human immunodeficiency virus (HIV). Accordingly, the dose of saquinavir may need to be reduced to avoid toxicity, and the doses of nelfinavir and atazanavir may need to be increased to maintain efficacy.
Pregnancy and lactation
Results from three prospective epidemiological studies (more than 1000 exposed outcomes) indicate no adverse effects of omeprazole on pregnancy or on the health of the foetus/newborn child. Omeprazole can be used during pregnancy.
Omeprazole is excreted in breast milk but is not likely to influence the child when therapeutic doses are used.
Drug Interactions - Because omeprazole can inhibit the cytochrome P-450 enzyme system, omeprazole may decrease the hepatic clearance of diazepam, phenytoin or warfarin, thereby enhancing their effects and causing potential toxicity. Additional monitoring and dosage adjustments may be required. Because omeprazole can increase gastric pH, drugs that require low gastric pH for optimal absorption (e.g., ketoconazole, ampicillin esters or iron salts) may have their absorption reduced. Although omeprazole causes bone marrow depression only rarely in humans, use with other drugs that cause bone marrow depression may lead to additive hematologic abnormalities.
Omeprazole side effects.
- back pain;
- blurred vision;
- burning or tingling of the lips, tongue, hands, or feet;
- confusion;
- constipation;
- cough;
- diarrhea;
- difficulty breathing or swallowing;
- dizziness;
- drowsiness;
- dry mouth;
- fast or pounding heartbeat;
- flushing (feeling of warmth);
- headache;
- hives;
- hoarseness;
- itching;
- muscle spasms, tightening, aching, or cramping;
- nausea;
- rash;
- seizures;
- stomach pain;
- sweating;
- swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs;
- vomiting;
Omeprazole Dosing Information
Usual Adult Omeprazole Dose for Duodenal Ulcer:
20 mg orally once a day before a meal. Most patients heal within 4 to 8 weeks.
Usual Adult Omeprazole Dose for Helicobacter pylori Infection:
Dual therapy: omeprazole 40 mg orally once a day in the morning plus clarithromycin 500 mg orally 3 times a day on days 1 to 14. Beginning on day 15, omeprazole 20 mg orally once a day in the morning on days 15 to 28.
Triple therapy: omeprazole 20 mg plus clarithromycin 500 mg plus amoxicillin 1000 mg all given orally twice a day for 10 days. If an ulcer is present at the initiation of therapy, continue omeprazole 20 mg orally once a day for an additional 18 days.
Study (n=294) - Canadian Adult Dyspepsia Empiric Treatment-Helicobacter pylori positive (CADET-Hp): omeprazole 20 mg, metronidazole 500 mg, and clarithromycin 500 mg, twice daily for 7 days.
Usual Adult Omeprazole Dose for Gastric Ulcer:
40 mg orally once a day before a meal for 4 to 8 weeks.
Usual Adult Omeprazole Dose for Erosive Esophagitis:
20 mg orally once a day before a meal. This dosage may be increased to 40 mg per day based on desired clinical response and patient tolerance. Studies have been completed up to 12 months for maintenance therapy of erosive esophagitis.
Usual Adult Dose for Zollinger-Ellison Syndrome:
Initial: 60 mg orally once a day. Dosage should be individualized to patient's needs.
Maintenance: doses up to 120 mg 3 times a day have been administered. Daily doses greater than 80 mg should be divided.
Usual Adult Dose for Gastroesophageal Reflux Disease:
Initial: 20 mg orally once a day before a meal for 4 to 8 weeks. This dosage may be increased to 40 mg per day if needed.
Maintenance: long-term treatment with doses of 10 to 20 mg per day may be required for maintenance therapy of refractory disease and appears to be safe.
Usual Adult Dose for Multiple Endocrine Adenomas:
Initial: 60 mg orally once a day before a meal. This dosage may be titrated based on desired clinical response and patient tolerance.
Maintenance: doses up to 120 mg 3 times a day have been administered. Daily doses greater than 80 mg should be divided.
Usual Adult Dose for Systemic Mastocytosis:
Initial: 60 mg orally once a day before a meal. This dosage may be titrated based on desired clinical response and patient tolerance.
Maintenance: doses up to 120 mg 3 times a day have been administered. Daily doses greater than 80 mg should be divided.
Usual Adult Dose for Dyspepsia:
Prevention of frequent heartburn: 20 mg orally once daily, before a meal, for 14 days.
Usual Pediatric Omeprazole Dose for Gastroesophageal Reflux Disease:
>2 years
<20 kg: 10 mg once a day.
>=20 kg: 20 mg once a day
Studies:
>1 year: 0.7 to 3.5 mg/kg/day, given in 2 divided doses, not to exceed 80 mg daily.
Study (n=115)
<1 year: 1 to 1.5 mg/kg once daily for 56 days. Omeprazole was administered orally as a 2 mg/mL bicarbonate suspension.
Usual Pediatric Omeprazole Dose for Erosive Esophagitis:
>1 years: 0.7 to 3.5 mg/kg/day (maximum 80 mg/day), for 3 months. Dosage increments of 0.7 mg/kg/day to achieve stomach pH of <4.
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Unknown - Wednesday, 27 April 2011
