Tacrolimus

Introduction

Tacrolimus is a drug which is used to inhibit and modulate the immune system. It is often used to inhibit transplant rejection, some autoimmune diseases and chronic inflammatory skin diseases. The active ingredient is derived from Gram-positive bacteria of the genus Streptomyces and shows structural similarity to the group of macrolide antibiotics. Tacrolimus was first approved in 1994. Due to its immunomodulatory effect, it has since been increasingly approved for other diseases (including as eye drops and mouth rinse).

Indications for Tacrolimus

After oral administration (in the form of tablets) it has an immunosuppressive effect and is used to inhibit transplant rejection (e.g. after kidney, liver or heart transplantation) and rarely in autoimmune reactions (e.g. ulcerative colitis, Crohn’s disease, myasthenia gravis). When applied locally to the skin (in the form of an ointment) Tacrolimus has an immunomodulatory effect and is often used in neurodermatitis (atopic eczema).

In addition, it has been integrated into the therapy of psoriasis (chronic inflammatory skin disease) in recent years. In the form of eye drops it is used for very dry eyes as part of keratoconjunctivitis sicca. As a component of mouthwashes, it is also used for inflammation of the oral mucosa.

Psoriasis is a chronic, non-inflammatory skin disease. The body’s immune system is directed against the body’s own structures in the skin. Depending on the severity of the inflammation, reddish, scaly spots form on the surface of the skin. Tacrolimus is used to suppress this autoimmune reaction by altering and suppressing the immunological processes in the skin. Compared to additionally used glucocorticoids (cortisone), Tacrolimus is characterized by a better tolerance – usually there is no skin atrophy (thin skin) and no increase of the intraocular pressure.

Side effects of Tacrolimus

Depending on the type of application (systemic or localized), different side effects can occur and these can vary in severity. In case of systemic use (often over a longer period of time) damage to the kidneys (nephrotoxicity) and damage to the nervous system (neurotoxicity) may occur. As a consequence, neurological disorders may occur (tremor, dizziness, visual disturbances, depression, insomnia).

In addition, high blood pressure, cramps and elevated blood sugar levels are possible during therapy. Due to the systemic inhibition of the immune system there is an increased susceptibility to infections. Furthermore, in studies a slightly increased risk of cancer (especially skin cancer) has been reported with long-term application of Tacrolimus – regular check-ups by a dermatologist and an adequate sun protection are necessary.

Further side effects with systemic application can be taken from the package insert. In case of topical, i.e. local application, a reddening with burning and itching may occur in the affected skin area in the first days after application of Tacrolimus. Also a feeling of heat in the affected area of the skin is possible.