"Unknown Risks" of non-steroid topical medications for atopic dermatitis.
BACKGROUND
Tacrolimus ointment is a nonsteroid treatment for atopic dermatitis which is both effective and has a minimal side-effect profile. However, some clinicians may be reluctant to use tacrolimus ointment due to the "unknown risks", meaning those that have not been uncovered in human studies conducted thus far. Therefore, the available animal data regarding the "unknown risks" of topical tacrolimus therapy are reviewed, and a discussion of the interpretation of this available but limited data is presented.


METHODS
Some of the fear on the part of clinicians regarding the use of topical tacrolimus may come from the results of animal studies which showed an increase in lymphoma and UV-induced skin cancer after treatment with topical tacrolimus in animal models of carcinogenesis. However, rigorous assessment of these studies suggest that it is somewhat likely that these represent a species-specific response to tacrolimus in an animal already predisposed to tumor formation, and therefore may not be relevant in assessing the possibility of an increased human health risk.


CONCLUSIONS
Animal and human studies suggest that topical tacrolimus is a safe alternative to topical steroids, with the major known adverse effect being a transient burning sensation, compared with the known adverse effects of topical steroids, including long-lasting ones. Therefore, in the opinion of the authors, currently available data, including animal studies, does not suggest that "unknown risks" of topical tacrolimus need be any more concerning than the known side-effects of the topical steroids.
McNeill
Anne Marie
AM
Phototherapy and Drug Research Unit, Department of Dermatology, University of California, San Francisco, San Francisco, CA 94143, USA.
Koo
John Y M
JY
D000287:Administration, Topical; D000818:Animals; D003876:Dermatitis, Atopic / Q000188:drug therapy*; D064420:Drug-Related Side Effects and Adverse Reactions; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D008223:Lymphoma / Q000139:chemically induced*; D012869:Skin Absorption; D012878:Skin Neoplasms / Q000139:chemically induced* / Q000503:physiopathology; D016559:Tacrolimus / Q000009:adverse effects* / Q000627:therapeutic use; D014466:Ultraviolet Rays / Q000009:adverse effects
D007166:Immunosuppressive Agents; D016559:Tacrolimus