What the FDA labels say about taking them together
Dimethyl fumarate and monomethyl fumarate
Monomethyl fumarate's FDA label of July 16, 2026 names dimethyl fumarate in its contraindications section; the dimethyl fumarate labels PlainMeds reads (2) do not name monomethyl fumarate. The monomethyl fumarate label: “Therefore, BAFIERTAM is contraindicated in patients currently taking dimethyl fumarate or diroximel fumarate.”
Check it at the source: the dimethyl fumarate FDA label on DailyMed (effective July 29, 2025, Macleods Pharmaceuticals Limited); the monomethyl fumarate FDA label on DailyMed (effective July 16, 2026, Banner Life Sciences LLC).
What does the dimethyl fumarate label say about monomethyl fumarate?
Dimethyl fumarate's label (effective July 29, 2025) and its 1 other brand-application label do not name monomethyl 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 monomethyl fumarate label say about dimethyl fumarate?
Monomethyl fumarate label, contraindicationsCONTRAINDICATIONS BAFIERTAM is contraindicated in patients: with known hypersensitivity to monomethyl fumarate, dimethyl fumarate, diroximel fumarate, or to any of the excipients of BAFIERTAM.
Monomethyl fumarate label, drug interactionsTherefore, BAFIERTAM is contraindicated in patients currently taking dimethyl fumarate or diroximel fumarate.
Monomethyl fumarate label, warnings and precautionsDuring the clinical trial, the patient experienced prolonged lymphopenia (lymphocyte counts predominantly <0.5x10 9 /L for 3.5 years) while taking dimethyl fumarate [see Warnings and Precautions ( 5.4 )].
Source: FDA drug label (BAFIERTAM), Banner Life Sciences LLC, effective July 16, 2026 (SPL set a161f9d4-70f1-4097-957a-eafb35d3274f), 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 | Monomethyl 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