Skip to content

Infliximab (Remicade)

This biologic may reduce symptoms of moderate to severe Crohn’s disease in people who have not responded to standard treatment. It may also help heal and reduce the number of fistulas. Fistulas are abnormal tunnels that connect from one part of an intestine to another, or from the intestine to the bladder, vagina, or skin. They often become infected and drain pus, mucus, or stool.

How given: intravenous (IV) injection

Common Side Effects:

  • Redness, swelling, itching, pain, rash, or bruising at the infusion site
  • Upper respiratory or sinus infections
  • Sore throat
  • Headache
  • Rash
  • Nausea
  • Coughing
  • Stomach pain

Other potential side effects: Like other biologics, there is a potential for more serious side effects, such as TB and sepsis, and there are rare cases of people who've gotten cancers such as lymphoma. 

Natalizumab (Tysabri)

Your doctor may recommend this drug if you have moderate to severe Crohn's disease, with signs of inflammation, when other treatments haven't worked or if you can't take them. If you take natalizumab, you should not also take other biologics or other drugs that block the immune system.

How given: intravenous (IV) injection

Common Side Effects:

  • Upper respiratory infections
  • Urinary tract infections
  • Headache
  • Depression
  • Tiredness
  • Diarrhea
  • Stomach pain
  • Rash

Other potential side effects: Natalizumab raises the risk of a very rare but potentially fatal brain infection called progressive multifocal leukoencephalopathy (PML). The drug also can cause allergic reactions and liver damage.

Vedolizumab (Entyvio)

The FDA approved this biologic in May 2014 to treat moderate to severe Crohn’s disease, especially when one or more other treatments are not working well enough.

How given:  intravenous (IV) infusion

Common side effects: 

  • Upper respiratory infections
  • Headache
  • Joint pain
  • Nausea
  • Fatigue
  • Fever
  • Rash
  • Pain in the hands and feet

Other potential side effects: Like other biologics, Vedolizumab may make serious infection, like TB and sepsis, more likely. There is also a risk of allergic reactions, liver damage, and the very rare but potentially fatal brain infection PML. 

Work Closely With Your Doctor

If your doctor prescribes biologics, she'll closely track your health to be sure the treatment works safely and effectively. So keep all appointments for lab work and doctor visits.

Tell your doctor about all prescription and over-the-counter drugs you take, as well as any supplements or natural remedies. Because some drugs can interact with other drugs, herbs, and supplements, it’s important not to start taking any new drug or treatment without first consulting your doctor. 

Also, tell your doctor about all of your medical conditions, such as heart failure. Let them know if your symptoms get worse or if you notice any new symptoms.