Cimzia (certolizumab pegol) and Humira (adalimumab) are two different medicines but they are from the same class of medications called tumor necrosis factor (TNF) inhibitors or blockers. Both medicines are approved to treat rheumatoid arthritis, Crohn's disease, plaque psoriasis, and psoriatic arthritis, but Humira also treats several other autoimmune inflammatory diseases as well. For some diseases, Humira is safe for children, while Cimzia is only indicated for adults.

Each drug has a different chemical structure and is manufactured using different technology, though they both block a step in the inflammatory immune process.

Another difference between the two medicines relates to pregnancy. Cimzia crosses the placenta in negligible amounts during pregnancy, while Humira actively crosses the placenta during the third trimester and may affect the immune response in exposed infants. Patients should work with their physician to weigh the benefits and risks of taking medication during pregnancy.

Both medicines come only as shots that are administered under the skin (called subcutaneous injection). The exact dose and how often the drug is given depends on which disease is being treated. In general, Humira is given every other week and Cimzia is given every four weeks.

In a head-to-head comparison published in the Lancet in 2016, the drugs had similar efficacy and safety among 915 randomized patients with rheumatoid arthritis, and the non-responder patients in one group were able to safely switch to the other drug.

Because TNF inhibitors work by blocking a step in the body's immune response, both of these medicines increase a person's risk for infections as a side effect.