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Prilosec (omeprazole) Delayed-Release Capsules, Prilosec (omeprazole magnesium) For Delayed Release Oral Suspension
Detailed View: Safety Labeling Changes Approved By FDA Center for Drug Evaluation and Research (CDER) – January and June 2011
WARNINGS AND PRECAUTIONS
Concomitant use of Prilosec with St John’s Wort or rifampin
- Drugs which induce CYP2C19 or CYP3A4 (such as St John’s Wort or rifampin) can substantially decrease omeprazole concentrations. Avoid concomitant use of Prilosec with St John’s Wort or rifampin. Warning and Precautions (5) section with information regarding interactions with diagnostic investigations for neuroendocrine tumors, and concomitant use with St. John’s Wort or rifampin.
Interactions with Investigations for Neuroendocrine Tumors
- Serum chromogranin A (CgA) levels increase secondary to drug induced decreases in gastric acidity. The increased CgA level may cause false positive results in diagnostic investigations for neuroendocrine tumors. Providers should temporarily stop omeprazole treatment before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g. for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary.
- with information regarding interactions with diagnostic investigations for neuroendocrine tumors, and concomitant use with tacrolimus, digoxin, St. John’s Wort or rifampin, and clopidogrel.
PATIENT PACKAGE INSERT
Tell your doctor about all of the medicines you take
- addition of St. John’s Wort (Hypericum perforatum) and Rifampin to the medication list
5 WARNING AND PRECAUTIONS
5.4 Diminished Anti-platelet Activity of Clopidogrel Due to Impaired CYP2C19 Function by Omeprazole
- Clopidogrel is a prodrug. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. The metabolism of clopidogrel to its active metabolite can be impaired by use with concomitant medications, such as omeprazole, that interfere with CYP2C19 activity. Avoid concomitant use of clopidogrel and omeprazole. Co-administration of clopidogrel with 80 mg omeprazole, a proton pump inhibitor that is an inhibitor of CYP2C19, reduces the pharmacological activity of clopidogrel if given concomitantly or if given 12 hours apart [see Drug Interactions (7)]