What the FDA labels say about taking them together
Diclofenac and rifampin
Diclofenac's FDA label (Zipsor) of March 1, 2026 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name diclofenac. The diclofenac label: “… toxicity of diclofenac whereas co- administration with CYP2C9 inducers (e.g. rifampin) may lead to compromised efficacy of diclofenac. …”
Check it at the source: the diclofenac FDA label on DailyMed (effective February 11, 2025, Haleon US Holdings LLC); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).
What does the diclofenac label say about rifampin?
Zipsor label (Assertio Specialty Pharmaceuticals LLC, March 1, 2026), drug interactionsClinical Impact Diclofenac is metabolized by cytochrome P450 enzymes, predominantly by CYP2C9. Co-administration of diclofenac with CYP2C9 inhibitors (e.g. voriconazole) may enhance the exposure and toxicity of diclofenac whereas co- administration with CYP2C9 inducers (e.g. rifampin) may lead to compromised efficacy of diclofenac. Intervention: A dosage adjustment may be warranted when diclofenac is administered with CYP2C9 inhibitors or inducers [ see Clinical Pharmacology () ]
Source: FDA drug label (Zipsor, NDA022202), Assertio Specialty Pharmaceuticals LLC, effective March 1, 2026 (SPL set ed2a8868-78eb-47b8-8f46-0f70e2891e07), via openFDA
Source: FDA drug label (Voltaren Arthritis Pain), Haleon US Holdings LLC, effective February 11, 2025 (SPL set 30a94282-0892-442a-aa10-6525cbd4fe88), via openFDA; the full label on DailyMed
What does the rifampin label say about diclofenac?
Rifampin's label (effective February 11, 2026) does not name diclofenac in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (rifampin), Lupin Pharmaceuticals, Inc., effective February 11, 2026 (SPL set b56004f0-f23d-47f6-80c7-39884fccbccc), 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
| Diclofenac | Rifampin | |
|---|---|---|
| Labeled for | Pain, Osteoarthritis, Rheumatoid arthritis, Migraine | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.0619 per tablet 75 mg tablet | $0.679 per capsule 300 mg capsule |
| Shortage now | A presentation being discontinued | In shortage |
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