What Are Calcineurin Inhibitors?

What is calcineurin?

Calcineurin is an enzyme that activates a specific component of the immune system known as T-cells. T-cells, or T-lymphocytes, are a type of white blood cell that communicates with other immune cells and attacks foreign pathogens.

What are calcineurin inhibitors?

Calcineurin inhibitors (CNIs) are medications that suppress or prevent an overreaction of the immune system. CNIs work by inhibiting calcineurin immune cells and inflammatory cytokines that are essential for T-cell synthesis.

Types of calcineurin inhibitors

The calcineurin family consists of three medications: cyclosporine, tacrolimus and pimecrolimus.

• Cyclosporine can be administered orally, by injection, or through eye drops. Cyclosporine is typically used to treat autoimmune diseases, such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease. Cyclosporine can also help prevent rejection of heart, liver, kidney, and other solid organ transplants.
• Tacrolimus is typically administered orally but may also be administered topically, sublingually, intravenously or rectally. Orally administered tacrolimus can be used to suppress the immune system in order to prevent organ rejection and to treat autoimmune diseases, such as rheumatoid arthritis and Crohn’s disease. When used as an ointment, tacrolimus can treat certain skin conditions, such as dermatitis and psoriasis.
• Pimecrolimus is only available as a topical ointment. It is often used to treat steroid-responsive skin conditions, such as vitiligo, eczema and psoriasis.

Side effects

The potential side effects of orally administered cyclosporine and tacrolimus are similar. Common side effects include an increased risk of secondary infections, liver or renal toxicity, arthralgias, muscle cramps, hypertension, and cardiac arrhythmias.

All topically applied calcineurin inhibitors increase the risk of secondary infections. Other common side effects include rashes, itching, acne and alopecia.