Which vitamins should you avoid with methotrexate on the same day?
The main vitamin to avoid is folic acid (and other folate supplements) only if your prescriber told you not to use them. In most standard methotrexate regimens, folate is actually recommended to lower side effects (like mouth sores, stomach upset, and some blood-related toxicity).
So the “avoid” answer depends on what you mean by “vitamin”:
- Don’t add extra folic/folate unless your clinician approves it. This is the one that people commonly mix up because some patients are already on folic acid.
- Avoid supplements that contain high-dose folic acid/folate on top of what your doctor already prescribed unless your prescriber says it’s okay (because your regimen may already include the needed dose).
Which supplement is most commonly problematic with methotrexate: folate vs vitamin B?
There are two broad categories that get confused:
- Folate/folic acid: Usually helpful with methotrexate side effects, not harmful.
- Vitamin B complex / “methylated” vitamins: These can include folate. If you take a B-complex that contains folic acid, it may effectively increase your folate intake beyond what your doctor intended.
If your methotrexate plan includes folic acid on a schedule (for example, weekly), ask your clinician or pharmacist whether your multivitamin or B-complex should be avoided the same day or adjusted.
What about “vitamin A,” “vitamin C,” or “vitamin D”?
Based on general medication-safety practice, there isn’t a well-known rule that you must avoid vitamin D, vitamin C, or vitamin A on the exact same day as methotrexate. The bigger issues are usually:
- High-dose supplements (especially if you’re also taking other meds),
- Liver stress from multiple supplements/alcohol,
- Blood count effects depending on dose and kidney function.
Because methotrexate sensitivity varies by dose, kidney function, and the reason you take it (rheumatoid arthritis, psoriasis, cancer), the safest approach is to confirm the specific product with your pharmacist.
The safest practical rule for “same-day vitamins”
- Check what your methotrexate schedule already includes. If you are prescribed folic acid, follow that plan exactly.
- Do not start or change multivitamins/B-complex/“immune support” products without asking your prescriber or pharmacist.
- Avoid high-dose supplement stacks (many contain folate or other overlapping ingredients).
Quick questions (so I can give a precise answer)
- What dose of methotrexate do you take (and is it weekly like many arthritis/psoriasis regimens, or another schedule)?
- Are you also taking folic acid (name and dose), or a multivitamin/B-complex?
- What condition is it for (arthritis/psoriasis vs chemotherapy)?
If you tell me the exact supplement names on your label, I can point out whether they contain folate/folic acid that could conflict with your prescribed methotrexate plan.