Omeprazole and supplements: 3 sourced interactions
Proton pump inhibitor, also sold as Prilosec, Prilosec OTC and Zegerid. Of these, 3 named by an FDA label or NIH page. Plus 1 food and drink line. Each links its source and the date it was checked.
From the Interaction Map Sources checked Oct 23, 2026
A combination missing here is not on our list; that does not mean it is safe together.
Omeprazole with supplements
Most serious first. Open a row for the mechanism, the source's words and the date checked.
Educational only. Check with your pharmacist or prescriber before changing anything you take.
Major
1St John's wortLabel or NIHThe FDA label names this pair (breakdown by liver enzymes).
major · Named by an FDA label or NIH page · Breakdown by liver enzymes
In the source’s own words; rated major from that wording, not from a study of the pair.
“Avoid 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 [see Drug Interactions (7)].”
“Decreased exposure of omeprazole when used concomitantly with strong inducers [see Clinical Pharmacology (12.3)]. Intervention: St. John’s Wort, rifampin: Avoid concomitant use with”
- FDA drug label (DailyMed) · PRILOSEC (omeprazole magnesium) for delayed-release oral suspension, Rx (Covis Pharma), section 7
- Checked Oct 23, 2026
Moderate
2IronLabel or NIHThe FDA label names this pair (absorption in the gut).
moderate · Named by an FDA label or NIH page · Absorption in the gut
In the source’s own words; rated moderate from that wording, not from a study of the pair.
“Drugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole)”
“Drugs Dependent on Gastric pH for Absorption (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole) Clinical Impact: Omeprazole can reduce the absorption of other drugs due to its effect on reducing intragastric acidity.”
“Because proton pump inhibitors, such as lansoprazole (Prevacid) and omeprazole (Prilosec), reduce the acidity of stomach contents, they can reduce iron absorption”
- FDA drug label (DailyMed) · PRILOSEC (omeprazole magnesium) for delayed-release oral suspension, Rx (Covis Pharma), section 7
- NIH Office of Dietary Supplements · Office of Dietary Supplements · Iron: Fact Sheet for Health Professionals, Interactions with Medications > Proton pump inhibitors
- Checked Oct 23, 2026
MagnesiumLabel or NIHAn NIH page names this pair (cause not established).
moderate · Named by an FDA label or NIH page · Cause not established
In the source’s own words; rated moderate from that wording, not from a study of the pair.
“Prescription proton pump inhibitor (PPI) drugs, such as esomeprazole magnesium (Nexium) and lansoprazole (Prevacid), can cause hypomagnesemia when taken for prolonged periods (typically more than a year)”
- NIH Office of Dietary Supplements · Office of Dietary Supplements · Magnesium: Fact Sheet for Health Professionals, Interactions with Medications > Proton pump inhibitors
- Checked Oct 23, 2026
Omeprazole with food and drink
Food and drink
1GrapefruitPredictedGrapefruit may raise Omeprazole levels: it slows CYP3A, an enzyme that breaks Omeprazole down.
moderate · Predicted from how each works, not established · Breakdown by liver enzymes
Predicted from what each is known to do, not studied as a pair and not established.
Grapefruit may raise Omeprazole levels: it slows CYP3A, an enzyme that breaks Omeprazole down.
- FDA table of drugs that interact with CYP enzymes · Grapefruit: CYP3A moderate inhibitor (Table 1, row "grapefruit juice", column "CYP Mod INH" (footnote 9: The effect of grapefruit juice varies widely among brands and is concentration-, dose-, and preparation-dependent. Studies have shown that it can be classified as a “strong CYP3A inhibitor” when a certain preparation was used (e.g., high dose, double strength) or more commonly as a “moderate CYP3A inhibitor” when another preparation was used (e.g., low dose, single strength).))
- FDA drug label (DailyMed) · Omeprazole: CYP3A substrate (PRILOSEC (omeprazole magnesium) for delayed-release oral suspension, Rx (Covis Pharma), section 12.3 Pharmacokinetics · Metabolism)
- Checked Oct 23, 2026
How these lines are sourced
Three kinds of line
- Studied in people (PubMed): PubMed records that were opened and read, graded A (several controlled studies, or a finding in the dosing guidance), B (at least one controlled human study) or C (case reports, observational data or mechanism only).
- Named by an FDA label or NIH page: quoted word for word from that page. Its severity comes from the source’s wording, not from a study of the pair.
- Predicted from how each works, not established: built from sourced facts about each substance, such as the FDA’s table of enzyme roles. Never rated major.
Interaction MapCheck Omeprazole with everything else you take, together
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- Previous in this topicNaproxen and supplements: 1 sourced interactionNaproxen (Aleve, Naprosyn) with supplements, by severity, each line studied in people or named by an FDA label or NIH page, with its source.
- Next in this topicPantoprazole and supplements: 2 sourced interactionsPantoprazole (Protonix) with supplements, by severity, each line studied in people or named by an FDA label or NIH page, with its source.
- Interaction MapCheck several medicines and supplements at once, each interaction sourced to PubMed, FDA labels or NIH; a pair we have no source for reads as not on our list, never as safe.
- St. John's wortSt.