Quick answer

Ask your pharmacist or doctor before combining. NIH says sulfasalazine inhibits the intestinal absorption of folate and can cause folate deficiency, and its label reports reduced absorption of folic acid. NIH advises people taking it to ask their provider whether to eat more folate, start a supplement, or do both.^1,2,3

Key facts

The sulfasalazine label reports reduced absorption of folic acid with the medicine and lists folate deficiency among reported effects.³
NIH's health professional sheet says patients taking sulfasalazine should ask their provider whether to increase dietary folate, start a folate supplement, or both.¹
The label's pregnancy section says the effect on folic acid may interfere with folic acid supplementation taken around conception.³
MedlinePlus says your doctor will order lab tests before and during treatment to check your response to sulfasalazine.⁴

Ask your pharmacist or doctor first

Sulfasalazine reduces how much folate the body absorbs and can lead to low folate. Its label reports reduced absorption of folic acid when the two are taken together.^1,2,3

On the medicine's label

Does sulfasalazine cause folate deficiency?

NIH says it can. Its health professional sheet describes sulfasalazine as used mainly for ulcerative colitis, and says it inhibits the intestinal absorption of folate and can cause folate deficiency. The consumer sheet says the medicine could reduce the body's ability to absorb folate and cause folate deficiency.^1,2

The label reports the effect in three places. Under drug interactions, it says reduced absorption of folic acid has been reported when the two are taken together. Impaired folic acid absorption appears among reported gastrointestinal reactions, and folate deficiency appears among reported metabolism and nutrition disorders.³

This pair is marked on-label: the medicine's own label says it. None of the passages above gives a figure for how often it happens, so nothing here tells you how likely deficiency is for you.³

Do you need to take folate with sulfasalazine?

NIH's answer is a question to put to your provider, not a rule. It says patients taking sulfasalazine should ask their health care provider whether they should increase their dietary folate intake, start a folate supplement, or both. The label reports the absorption effect but does not tell patients to take folic acid, and the MedlinePlus page does not mention it.^1,3,4

That is why this page gives no amount. Some people get folate from food, some from a multivitamin or prenatal product, and some from a prescribed tablet, and your prescriber needs to know about all of it.

Is it folate or folic acid, and does the form matter?

The label says folic acid, and NIH says folate. NIH's consumer sheet explains that folic acid is the form of folate used in fortified foods and most dietary supplements. The sources checked do not compare folic acid with other forms for people taking sulfasalazine. That is not a finding either way, so give your pharmacist the exact name on your label.^1,2,3

Tests, pregnancy and what else to mention

MedlinePlus says your doctor will order lab tests before and during treatment, and the label calls for regular blood counts and liver function tests. NIH adds that serum folate is sensitive to recent intake, while red blood cell folate gives a longer-term picture, so a result taken soon after a folic acid supplement may mostly reflect that recent intake.^1,3,4

The label's pregnancy section says oral sulfasalazine inhibits the absorption and metabolism of folic acid, which may interfere with folic acid supplementation. If you are pregnant or planning a pregnancy, raise this with your prescriber early.³

Questions for your pharmacist or prescriber

Should I eat more folate-rich food, take a supplement, or both?
Which folate or folic acid products do I already take, including a multivitamin or prenatal?
Has my folate been measured, and when is the next blood test?
Does my plan change if I am pregnant or could become pregnant?

Questions people ask

Does sulfasalazine cause folate deficiency?

NIH says sulfasalazine inhibits the intestinal absorption of folate and can cause folate deficiency. Its label reports reduced absorption of folic acid and lists folate deficiency among reported effects.^1,3

Do you need to take folate with sulfasalazine?

NIH says to ask your provider whether to increase dietary folate, start a folate supplement, or both. The label does not tell patients to take folic acid, so the decision is your prescriber's.^1,3

Can you take folic acid with sulfasalazine?

Ask first. The label reports reduced folic acid absorption with sulfasalazine, so your prescriber decides whether a supplement is needed and how much.³

Does sulfasalazine affect folic acid taken in pregnancy?

The label says oral sulfasalazine inhibits the absorption and metabolism of folic acid, which may interfere with folic acid supplementation. Ask your prescriber if you are pregnant or planning a pregnancy.³

See what we make

Every product shows its whole label and what its lab report covers. The store opens soon.

See the Full Measure line

Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.