What the FDA labels say about taking them together
Mefenamic acid and pemetrexed
Mefenamic acid's FDA label of April 20, 2026 names pemetrexed in its drug interactions section; the pemetrexed labels PlainMeds reads (4) do not name mefenamic acid. The mefenamic acid label: “Concomitant use of mefenamic acid and pemetrexed may increase the risk of pemetrexed- associated myelosuppression, renal, and GI toxicity.”
Check it at the source: the mefenamic acid FDA label on DailyMed (effective April 20, 2026, Lupin Pharmaceuticals, Inc.); the pemetrexed FDA label on DailyMed (effective October 8, 2025, Avyxa Pharma, LLC).
What does the mefenamic acid label say about pemetrexed?
Mefenamic acid label, drug interactionsPemetrexed Clinical Impact: Concomitant use of mefenamic acid and pemetrexed may increase the risk of pemetrexed- associated myelosuppression, renal, and GI toxicity (…). Intervention: During concomitant use of mefenamic acid and pemetrexed, in patients with renal impairment whose creatinine clearance ranges from 45 to 79 mL/min, monitor for myelosuppression, renal and GI toxicity. …
Source: FDA drug label (Mefenamic Acid), Lupin Pharmaceuticals, Inc., effective April 20, 2026 (SPL set d15733a9-d5fd-4d5f-86ce-e7ed8c706c7f), via openFDA; the full label on DailyMed
What does the pemetrexed label say about mefenamic acid?
Pemetrexed's label (effective October 8, 2025) and its 3 other brand-application labels do not name mefenamic acid in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (AXTLE), Avyxa Pharma, LLC, effective October 8, 2025 (SPL set 9582c46c-d8b0-44b7-a2ee-9c86f5e9b7b1), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Mefenamic acid | Pemetrexed | |
|---|---|---|
| Labeled for | Pain | Lung cancer |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.948 per capsule 250 mg capsule | n/a |
| Shortage now | No current entry | A presentation being discontinued |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once