What the FDA labels say about taking them together
Dimethyl fumarate and diroximel fumarate
Diroximel fumarate's FDA label of May 29, 2025 names dimethyl fumarate in its contraindications section; the dimethyl fumarate labels PlainMeds reads (2) do not name diroximel fumarate. The diroximel fumarate label: “CONTRAINDICATIONS VUMERITY is contraindicated in patients With known hypersensitivity to diroximel fumarate, dimethyl fumarate, or to any of the excipients of VUMERITY.”
Check it at the source: the dimethyl fumarate FDA label on DailyMed (effective July 29, 2025, Macleods Pharmaceuticals Limited); the diroximel fumarate FDA label on DailyMed (effective May 29, 2025, Biogen Inc.).
What does the dimethyl fumarate label say about diroximel fumarate?
Dimethyl fumarate's label (effective July 29, 2025) and its 1 other brand-application label do not name diroximel fumarate in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Dimethyl Fumarate), Macleods Pharmaceuticals Limited, effective July 29, 2025 (SPL set f8ada3e3-55c0-43e3-95b9-c6d11ffc42dd), via openFDA; the full label on DailyMed
What does the diroximel fumarate label say about dimethyl fumarate?
Diroximel fumarate label, contraindicationsCONTRAINDICATIONS VUMERITY is contraindicated in patients With known hypersensitivity to diroximel fumarate, dimethyl fumarate, or to any of the excipients of VUMERITY.
Diroximel fumarate label, drug interactionsDRUG INTERACTIONS 7.1 Concomitant Dimethyl Fumarate VUMERITY is contraindicated in patients currently taking dimethyl fumarate, which is also metabolized to monomethyl fumarate.
Diroximel fumarate label, warnings and precautionsDuring the clinical trial, the patient experienced prolonged lymphopenia (lymphocyte counts predominantly <0.5 × 10 9 /L for 3.5 years) while taking dimethyl fumarate [see Warnings and Precautions ( 5.4 )].
Source: FDA drug label (Vumerity), Biogen Inc., effective May 29, 2025 (SPL set 2d74414f-6b83-4ea2-9a95-3cecabbce774), 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
| Dimethyl fumarate | Diroximel fumarate | |
|---|---|---|
| Labeled for | Multiple sclerosis | Multiple sclerosis |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.467 per capsule 240 mg capsule | n/a |
| 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