Professional Information

Omeprazole

Pronouncation: (oh-MEP-ra-zole)
Class: GI agent, proton pump inhibitor, Helicobacter Pylori agent

Trade Names:
Prilosec
- Capsules, delayed-release 10 mg
- Capsules, delayed-release 20 mg
- Capsules, delayed-release 40 mg

Trade Names:
Prilosec OTC
- Tablets, delayed-release 20 mg

Losec (Canada)

Pharmacology

Feedback for Omeprazole

As a treatment for...	Avg User Ratings [?]
Erosive Esophagitis	1 comments Rate it!	10
Duodenal Ulcer	2 comments Rate it!	9.0
Gastroesophageal Reflux Disease	3 comments Rate it!	8.1

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Suppresses gastric acid secretion by blocking acid (proton) pump within gastric parietal cell.

Pharmacokinetics

Absorption

Absorption is rapid. T _max is 0.5ߙto 3.5ߙh. Bioavailability is 30% to 40% and increases upon repeat administration.

Distribution

95% is protein bound.

Metabolism

Extensive in the liver.

Elimination

Little is unchanged in the urine. Approximately 77% is eliminated as 6ߙmetabolites; the remainder is eliminated in the feces. The t _½ is 0.5 to 1 h. Total body Cl is 500 to 600 mL/min.

Duration

Up to 72 h.

Special Populations

Renal Function Impairment

There is slight increase in bioavailability in chronic renal function impairment. No dose adjustment necessary.

Hepatic Function Impairment

In chronic hepatic disease, bioavailability is increased; plasma t _½ is increased to 3 h; plasma Cl is decreased. Consider dose adjustment.

Elderly

The elimination rate is decreased. Bioavailability is increased. No dosage adjustment is necessary.

Race

AUC is increased approximately 4-fold in Asian patients. Consider dose adjustment.

Indications and Usage

Short-term treatment of active duodenal ulcer and gastroesophageal reflux disease (GERD), including erosive esophagitis and symptomatic GERD; long-term treatment of pathologic hypersecretory conditions (eg, Zollinger-Ellison syndrome, multiple endocrine adenomas, systemic mastocytosis); to maintain healing of erosive esophagitis; in combination with clarithromycin to eradicate H. pylori , use clarithromycin and amoxicillin in combination with omeprazole in patients with a 1-yr history of duodenal ulcers or active duodenal ulcers to eradicate H. pylori ; short-term treatment of active benign gastric ulcer; heartburn.

Unlabeled Uses

Posterior laryngitis.

Contraindications

Standard considerations.

Dosage and Administration

Active Duodenal Ulcer
Adults

PO 20 mg/day for 4 to 8 wk.

GERD
Adults (without esophageal lesions)

PO 20 mg/day for 4 wk.

Adults (with erosive esophagitis)

PO 20 mg/day for 4 to 8 wk.

Children 2 yr of age and older (GERD or other acid-related disorders)

PO Weighing less than 20 kg, the dose is 10 mg/day. Weighing 20 kg or more, the dose is 20 mg/day.

Erosive Esophagitis
Adults

PO 20 mg/day for 4 to 8 wk. For maintenance treatment, give 20 mg/day.

Pathologic Hypersecretory Conditions
Adults

PO For initial dose, give 60 mg/day. Dosages up to 120 mg 3 times daily have been given. Divide daily doses of more than 80 mg.

H. pylori
Adults (triple therapy)

PO Omeprazole 20 mg plus clarithromycin 500 mg plus amoxicillin 1,000 mg each given 2 times daily for 10 days; continue omeprazole 20 mg/day for an additional 18 days if an ulcer is present at start of therapy.

Adults (dual therapy)

PO Omeprazole 40 mg once daily plus clarithromycin 500 mg 3 times daily for 14 days; continue omeprazole 20 mg/day for an additional 14 days if an ulcer is present at start of therapy.

Gastric Ulcer
Adults

PO 40 mg once daily for 4 to 8 wk.

Heartburn (OTC)
Adults

PO 1 tablet (20 mg) daily for 14 days. The 14-day course may be repeated every 4 mo.

Storage/Stability

Store tablets at controlled room temperature (68° to 77°F). Protect tablets from high heat, humidity, and moisture. Store capsules at controlled room temperature (59° to 86°F). Protect capsules from light and moisture.

Drug Interactions

Atazanavir

Atazanavir plasma concentrations may be reduced, decreasing the efficacy.

Benzodiazepines

Cl of benzodiazepines may be decreased.

Cilostazol, tacrolimus

Plasma levels may be increased by omeprazole, increasing the therapeutic effects and adverse reactions.

Clarithromycin

Omeprazole and clarithromycin plasma concentrations may be elevated.

Drugs depending on gastric pH for bioavailability (eg, ampicillin, cyanocobalamin, digoxin, ketoconazole, indinavir, iron salts)

Absorption of these drugs may be affected.

Phenytoin

Decreased plasma Cl and increased phenytoin t _½ .

St. John's wort

Omeprazole plasma levels may be reduced, decreasing the therapeutic effect.

Warfarin

Increased INR and PT, which may lead to abnormal bleeding and increase the risk of death.

Laboratory Test Interactions

None well documented.

Adverse Reactions

CNS

Headache (7%); dizziness (2%); asthenia (1%).

Dermatologic

Rash (2%).

GI

Abdominal pain (5%); diarrhea, nausea (4%); flatulence, vomiting (3%); acid regurgitation, constipation (2%).

Musculoskeletal

Back pain (1%).

Respiratory

Upper respiratory tract infection (2%); cough (1%).

Precautions

Pregnancy

Category C .

Lactation

Excreted in breast milk.

Children

Safety and efficacy not established in children younger than 2 yr of age.

Atrophic gastritis

Has been reported in gastric corpus biopsies in patients treated with long-term omeprazole.

Overdosage

Symptoms

Blurred vision, confusion, diaphoresis, drowsiness, dry mouth, flushing, headache, nausea, tachycardia, vomiting.

Patient Information

Instruct patient using OTC omeprazole tablets to carefully read package instructions regarding warnings and dosing instructions. Advise patient to swallow tablet whole and not to split, crush, or chew tablet.
Instruct patient to take each dose on an empty stomach, at least 1 h before eating.
Instruct patient to swallow capsules whole and not to open, crush, or chew the capsule.
Advise patient having difficulty swallowing the capsule to open it and gently mix the pellets with 1 Tbsp of cool or cold applesauce and then immediately swallow the mixture without chewing. Remind patient not to crush or chew the pellets and not to prepare the pellet/applesauce mixture ahead of time or store for future use.
Remind patient that omeprazole is to be taken every day and not as needed or only when symptoms are present.
Inform patient that antacids may be taken concurrently with omeprazole.
Instruct patient to report any of the following to health care provider: bloody or coffee ground-like vomit; black, tarry stools; recurrent heartburn; recurrent indigestion or abdominal pain; increasing need for antacid use; bothersome side effects (eg, headache, constipation, gas).