What Is a TNF Inhibitor?

Medically Reviewed by David Zelman, MD on December 06, 2022
Written by Susan Bernstein
4 min read

TNF inhibitors are drugs that help stop inflammation. They're used to treat diseases like rheumatoid arthritis (RA), juvenile arthritis, psoriatic arthritis, plaque psoriasis, ankylosing spondylitis, ulcerative colitis (UC), and Crohn's disease.

They're also called TNF blockers, biologic therapies, or anti-TNF drugs.

There are many TNF inhibitors that have been approved by the FDA. Your doctor will help find one that is available and that's best for you:

TNF inhibitors are antibodies made in a lab from human or animal tissue. (Your body makes antibodies to fight off infections.) Once they're put into your blood, they cause a reaction in your immune system that blocks inflammation.

Your immune system makes a substance called tumor necrosis factor (TNF). Usually, your body keeps your TNF levels steady. But if you have an autoimmune disease like RA, something goes wrong. You start making too much TNF, and that leads to inflammation.

Inflammation that's out of control can damage your body. You might have pain or swelling or feel ill. These drugs block the action of TNF.

Most people feel better 2 to 4 weeks after their first dose. After 3 to 6 months, your symptoms may improve even more.

Some TNF inhibitors, including Cimzia, Humira, Enbrel, Erelzi, and Simponi, are given as shots under the skin. You'll get your first one or two at your doctor's office; then your doctor or a nurse will show you how to give them to yourself. Once you get comfortable with that, pre-filled shots can be shipped to your home.

Every 1 to 4 weeks, you'll inject your TNF inhibitor under the skin of your thigh or abdomen. You can use a different spot each time.

Remicade, Inflectra, and Simponi Aria, a version of Simponi, are given as infusions at a clinic or your doctor's office. While you lie still, it's slowly dripped into your vein through a tube. For Remicade, each session can take around 2 hours, and you'll need treatment every 4 to 8 weeks. With Simponi Aria, the sessions last 30 minutes. After two starter doses one month apart, they're given once every 8 weeks.

Your doctor may have you use a TNF inhibitor in combination with other drugs, such as methotrexate, prednisone, hydroxychloroquine (Plaquenil), leflunomide (Arava), or sulfasalazine (Azulfidine).

You may have to take these medications for a long time. If you go off them because you feel better, your inflammation can come back. Some people can cut down their dose instead of stopping the drugs altogether. Always take your medication as your doctor prescribes.

Like any drug, TNF inhibitors may have side effects. You may have redness, burning, or itching where the needle goes into your skin. This usually goes away in a few days.

Other possible side effects include:

A few people have a serious allergic reaction. If your lips swell, you have trouble breathing, or you feel dizzy, it could be an allergic reaction. Seek emergency care right away.

If one TNF inhibitor doesn't work well for you, your doctor may switch you to another to see if it works better.

Because TNF inhibitors tamp down your immune system to stop inflammation, they can make it harder for you to fight off infections. You may be at higher risk for getting colds, flu, urinary tract infections, or even tuberculosis (TB).

Your doctor probably will test you for TB and hepatitis B before you start taking a TNF inhibitor to make sure you don't have either of those without knowing it. The drugs can make the effects of those infections worse.

If you need antibiotics for an infection, you may have to stop taking your TNF inhibitor until the infection is cleared up.

It's rare, but you also could be at higher risk of getting cancer if you take TNF inhibitors, including lymphoma or skin cancer. Some people may get serious brain reactions. Those with heart failure or multiple sclerosis shouldn't take these drugs.

You probably shouldn't take your TNF drug while pregnant because doctors don't yet know how they might affect your unborn baby. You may be able to take other treatments for your inflammation while you are pregnant.

You should make sure you're up to date on all vaccines before taking TNF medications because after you start taking them, your immune system could be diminished. And you shouldn't get live viruses while taking these drugs because of possible adverse reactions and they can interfere with how well the vaccines work.