omeprazole (Prilosec, Zegerid, Losec, Medral)
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Introduction
Tradename: Prilosec, Losec in Canada, Medral in Mexico (over the counter 2003)
Indications
- short-term treatment of severe erosive esophagitis
- short-term treatment of gastroesophageal reflux disease
- pathologic hypersecretory conditions
- duodenal ulcer
- dyspepsia, superior to ranitidine[9]
- component of multidrug regimen used to treat H pylori
Dosage
- 20 mg PO QD
- pathologic hypersecretory conditions
- take before 30 minutes before eating[17]
- capsule should be swallowed whole, not chewed, crushed or opened
Capsules: 10 mg, 20 mg, 40 mg.
Tabs: (OTC form 20 mg tablets (Mg+2 salt) {$1/tab, 2003})[6]
Injection: ? for IV infusion (same dose as PO)[7]
Zegerid: powder for oral suspension (immediate release) 20 mg packets (460 mg Na+/packet)
Pharmacokinetics
- decreased stability in acid pH; capsules consist of enteric-coated granules
- protein-binding 95%
- extensively metabolized in the liver
- metabolized by cyt P450 2C19
- inhibits cyt P450 2C19
- elimination 1/2life: 0.5-1.5 hours
elimination via liver
1/2life = 0.5-1.5 hours
protein binding = 95 %
Adverse effects
- common (1-10%)
- uncommon (< 1%)
- increased risk of hip fracture[15]
- tubulointerstitial nephritis[16]
- no increased risk of heart attack[11]
* Omeprazole produced dose-related increase in gastric carcinoid tumors in rats (long term, 2 year study).
* short-term studies in humans (up 2-11 years) have not detected an increase risk of gastric tumors[3].
Drug interactions
- decreased absorption of ketoconazole & itraconazole due to increase in gastric pH
- increased 1/2life of diazepam (25-50%)[5]
- increased serum levels of:
- any drug which inhibits cyt P450 2C19 can increase omeprazole levels
- omeprazole inhibits cyt P450 2C19
- may increase levels of drugs metabolized by cyt P450 2C19
- may inhibit its own metabolism
- omeprazole induces cyt P450 1A2
- may diminish levels of drugs metabolized by cyt P450 1A2
- omeprazole may diminish antiplatelet effect of clopidogrel via inhibition of cyt P450 2C19
- may cut effect of clopidogrel in half[13]
- clopidogrel requires activation by cyt P450 2C19
- pantoprazole & lansoprazole do not inhibit cyt P450 2C19
- drug interaction(s) of levothyroxine with proton pump inhibitors
- drug interaction(s) of palbociclib with proton pump inhibitors
- drug interaction(s) of methotrexate with proton pump inhibitors
- drug interaction(s) of bisphosphonates with proton pump inhibitors
- drug interaction(s) of aspirin with proton pump inhibitors
- drug interaction(s) of antiplatelet agents with proton pump inhibitors
- drug interaction(s) of clopidogrel with proton pump inhibitors
- drug interaction(s) of ginko biloba with proton pump inhibitors
Test interactions
- hypergastrinemia occurs secondary to hypochlorhydria
Mechanism of action
- proton pump inhibitor
- interacts with sulfhydryl groups in proton pump
- inactive at neutral pH
More general terms
More specific terms
Additional terms
- cytochrome p450 1A2 (cytochrome P3-450, phenacetin deethylase, cytochrome p450-4, CYP1A2)
- cytochrome P450 2C19 (cytochrome P450 2C17, cytochrome P450 11A, mephenytoin 4-hydroxylase, cytochrome P450 254C, CYP2C19)
Component of
- amoxicillin/omeprazole/rifabutin
- magnesium hydroxide/omeprazole/sodium bicarbonate
- amoxicillin/clarithromycin/omeprazole
- omeprazole/sodium bicarbonate
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 3.0 3.1 a) Journal Watch, Mass Med Soc 20(11):88 (June) 2000 b) Klinkenberg-Knoll et al Gastroenterology 118:661, 2000
- ↑ Prescriber's Letter 13(3): 2006 Cytochrome P450 drug interactions Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=220233&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 5.0 5.1 Prescriber's Letter 9(12):67 2002
- ↑ 6.0 6.1 Prescriber's Letter 10(12):69 2003
- ↑ 7.0 7.1 Barkun A et al, Ann Intern Med 139:843, 2003 PMID: https://www.ncbi.nlm.nih.gov/pubmed/14623622
- ↑ Prescriber's Letter 11(12): 2004 New Formulation: Zegerid (Omeprazole Powder for Oral Suspension) Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=201208&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 9.0 9.1 Journal Watch 25(17):140, 2005 Veldhuyzen van Zanten SJ, Chiba N, Armstrong D, Barkun A, Thomson A, Smyth S, Escobedo S, Lee J, Sinclair P. A randomized trial comparing omeprazole, ranitidine, cisapride, or placebo in helicobacter pylori negative, primary care patients with dyspepsia: the CADET-HN Study. Am J Gastroenterol. 2005 Jul;100(7):1477-88. PMID: https://www.ncbi.nlm.nih.gov/pubmed/15984968
- ↑ Department of Veterans Affairs, VA National Formulary
- ↑ 11.0 11.1 FDA MedWatch http://www.fda.gov/medwatch/safety/2007/safety07.htm#Omeprazole
- ↑ Prescriber's Letter 14(9): 2007 Preliminary information for Prilosec and Nexium Safety Review Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=2309205&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 13.0 13.1 Prescriber's Letter 15(11): 2008 Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=241114&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ FDA Alert, 11/17/2009 Information for Healthcare Professionals: Update to the labeling of Clopidogrel Bisulfate (marketed as Plavix) to alert healthcare professionals about a drug interaction with omeprazole (marketed as Prilosec and Prilosec OTC) http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/DrugSafetyInformationforHeathcareProfessionals/ucm190787.htm
- ↑ 15.0 15.1 Geriatric Review Syllabus, 9th edition (GRS9) Medinal-Walpole A, Pacala JT, Porter JF (eds) American Geriatrics Society, 2016
- ↑ 16.0 16.1 Medical Knowledge Self Assessment Program (MKSAP) 17, American College of Physicians, Philadelphia 2015
- ↑ 17.0 17.1 NEJM Knowledge+