What the FDA labels say about taking them together
Mefenamic acid and nabumetone
Mefenamic acid's FDA label of April 20, 2026 names nabumetone in its drug interactions section; nabumetone's label does not name mefenamic acid itself but warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)). 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 nabumetone FDA label on DailyMed (effective January 13, 2025, ScieGen Pharmaceuticals Inc).
What does the mefenamic acid label say about nabumetone?
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 (…). … regarding potential interaction between pemetrexed and NSAIDs with longer half-lives (e.g., meloxicam, nabumetone), patients taking these NSAIDs should interrupt dosing for at least five days before, the day of, and two days following pemetrexed administration.
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 nabumetone label say about mefenamic acid?
Nabumetone's label does not name mefenamic acid itself; it warns about its class (NSAIDs (nonsteroidal anti-inflammatory drugs)):
Nabumetone label, boxed warningNSAIDs 1 cause an increased risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal.
Nabumetone label, boxed warningCardiovascular Thrombotic Events Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal.
Source: FDA drug label (Nabumetone), ScieGen Pharmaceuticals Inc, effective January 13, 2025 (SPL set 80c6888d-03b4-44f3-b94d-bcf5154ceae5), 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 | Nabumetone | |
|---|---|---|
| Labeled for | Pain | Osteoarthritis, Rheumatoid arthritis |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.948 per capsule 250 mg capsule | $0.128 per tablet 500 mg tablet |
| Shortage now | No current entry | No current entry |
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