The short answer
Iron tablets and mefenamate can each cause GI problems, but added injury from the exact combination is not established. Review persistent symptoms and the reason for iron treatment with your clinician.
What this answer covers
Oral iron tablets with oral mefenamic acid 250 mg capsules. Dietary iron, liquid formulations and intravenous iron are distinct exposures.
- Supplement or preparation
- Iron
- Medication ingredient
- mefenamate
Iron tablets can cause local injury
An original pathology study found that oral iron deposits often accompanied erosions or reactive injury in the stomach and esophagus of selected patients undergoing endoscopy. Some deposits, particularly in the duodenum, occurred without erosion. The study does not give a risk rate for all people taking iron.
The exact combination was not tested
Oral mefenamic acid 250 mg capsules can cause serious GI bleeding and ulcers. That makes persistent symptoms important to review, but separate risks from iron tablets and the NSAID do not prove a measured increase when taken together. Oral tablet findings also do not establish the effect of intravenous iron.
Find the reason iron is needed
The drug label recommends checking hemoglobin or hematocrit when anemia symptoms occur. Anemia can have several causes, including GI blood loss, and should not simply be treated by increasing iron without assessment. If iron was prescribed, ask the clinician about continued need, dose and formulation.
Know when to get help
oral mefenamic acid 250 mg capsules can cause serious GI bleeding even without a supplement. Seek urgent care for vomiting blood or black, tarry stools, and report persistent stomach pain or unusual bleeding. Tell your prescriber about other pain medicines, aspirin and anticoagulants. A few hours of separation has not been shown to prevent an added bleeding effect.
Evidence and practical considerations
Side effects & toxicity
An increased GI-injury rate specifically from iron with mefenamate has not been established.
- Exact scope
- Oral iron tablets with oral mefenamic acid 250 mg capsules. Dietary iron, liquid formulations and intravenous iron are distinct exposures. with Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
- Medication form and route
- Oral
What remains uncertain
- Separate oral tablet injury and NSAID toxicity do not establish additive exact-pair harm; selected biopsy series is not all-user incidence.
Factors that may matter: Exact preparation and dose; Fasting versus fed dosing; Bleeding and ulcer history; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Prescription oral oral mefenamic acid 250 mg capsules users; short human pharmacology studies where described.
Short-term acute pain up to seven days and primary dysmenorrhea indications. Serious GI warnings; magnesium hydroxide raises peak concentration and AUC in a small human study.
How this applies: Exact current product label. Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
Exact oral product label; no measured botanical co-use incidence. Ingredient, route, preparation and comparator differences must be retained.
Source 2: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients with iron-deficiency anemia undergoing endoscopy, plus retrospectively selected biopsy cases.
Iron deposition frequently accompanied esophageal or gastric erosion/reactive injury; duodenal deposition often lacked erosion.
How this applies: Indirect for oral mefenamic acid 250 mg capsules co-use; exact preparation and endpoint retained.
Abstract-only; attempted original PDF failed. Selected endoscopy population, not all iron users. No oral mefenamic acid 250 mg capsules combination comparison; deposition alone is not always injury and oral tablet findings do not establish risk for all routes.
Source 3: Medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Terminology.
mefenamate is IN. Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
How this applies: Exact identity.
Not clinical evidence.
Research assessment: · Open full citations ↗
Side effects & toxicity
Persistent GI symptoms during oral iron and mefenamate treatment deserve assessment of the formulation and the reason for anemia.
- Exact scope
- Oral iron tablets with oral mefenamic acid 250 mg capsules. Dietary iron, liquid formulations and intravenous iron are distinct exposures. with Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
- Medication form and route
- Oral
What remains uncertain
- Clinical precaution based on separate injury evidence. Do not assume all iron-related dark stools are bleeding or dismiss symptomatic bleeding as an iron effect.
Factors that may matter: Exact preparation and dose; Fasting versus fed dosing; Bleeding and ulcer history; Other medicines.
Read the supporting source summaries
Source 1: Current prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Prescription oral oral mefenamic acid 250 mg capsules users; short human pharmacology studies where described.
Short-term acute pain up to seven days and primary dysmenorrhea indications. Serious GI warnings; magnesium hydroxide raises peak concentration and AUC in a small human study.
How this applies: Exact current product label. Exact mefenamate IN 257844 linked by current RxNorm to mefenamic acid PIN 6693. The inspected oral acid capsules supply the explicit ingredient bridge, not meclofenamate or a different fenamate.
Exact oral product label; no measured botanical co-use incidence. Ingredient, route, preparation and comparator differences must be retained.
Source 2: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients with iron-deficiency anemia undergoing endoscopy, plus retrospectively selected biopsy cases.
Iron deposition frequently accompanied esophageal or gastric erosion/reactive injury; duodenal deposition often lacked erosion.
How this applies: Indirect for oral mefenamic acid 250 mg capsules co-use; exact preparation and endpoint retained.
Abstract-only; attempted original PDF failed. Selected endoscopy population, not all iron users. No oral mefenamic acid 250 mg capsules combination comparison; deposition alone is not always injury and oral tablet findings do not establish risk for all routes.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Sources checked and article drafted. | |
| Research summary published |
Article revision: 6fabc79901a81aac
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.