Skin and systemic pharmacokinetics of tacrolimus following topical application of tacrolimus ointment in adults with moderate to severe atopic dermatitis

• Published in: British journal of dermatology (1951) Vol. 160; no. 3; pp. 665 - 669
• Main Authors: Undre, N.A., Moloney, F.J., Ahmadi, S., Stevenson, P., Murphy, G.M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2009; Wiley-Blackwell
• Subjects: Adult; Aged; Allergic diseases; atopic dermatitis; Biological and medical sciences; Biopsy; Dermatitis, Atopic - drug therapy; Dermatitis, Atopic - metabolism; Dermatitis, Atopic - pathology; Dermatology; Female; Humans; Immunopathology; Immunosuppressive Agents - administration & dosage; Immunosuppressive Agents - pharmacokinetics; Immunosuppressive Agents - therapeutic use; Male; Medical sciences; Middle Aged; Ointments; pharmacokinetics; Skin - metabolism; Skin - pathology; Skin Absorption; Skin allergic diseases. Stinging insect allergies; Tacrolimus - administration & dosage; Tacrolimus - pharmacokinetics; Tacrolimus - therapeutic use; tacrolimus ointment; Treatment Outcome; Young Adult; Human; Allergy; Immunopathology; tacrolimus ointment; Skin disease; Calcineurin inhibitor; Dermatology; Systemic; Ointment; Atopy; Immunomodulator; Local administration; Tacrolimus; Atopic dermatitis; Adult; Skin; Disseminated; Immunosuppressive agent; Severe; Pharmacokinetics; Topical administration
• ISSN: 0007-0963; 1365-2133
• DOI: 10.1111/j.1365-2133.2008.08974.x

Summary Background  Systemic exposure to tacrolimus following topical application of tacrolimus ointment is minimal. There are, however, no data on the distribution of tacrolimus in the skin. Objectives  To assess the distribution of tacrolimus in the skin and the systemic pharmacokinetics of tacrolimus in adults with moderate to severe atopic dermatitis after first and repeated application of tacrolimus ointment. Methods  We investigated skin distribution of topically applied tacrolimus and systemic pharmacokinetics of percutaneously absorbed tacrolimus in adults with atopic dermatitis after topical application of tacrolimus 0·1% ointment twice daily for 2 weeks. Tacrolimus concentrations were assessed in full‐thickness skin biopsies and blood samples. Results  Of 14 patients, 11 completed treatment and were analysed. Mean ± SD tacrolimus concentrations in the skin at 24 h after first and last ointment applications were 94 ± 20 and 595 ± 98 ng cm−3, respectively. At 168 h after stopping treatment, values were 97% lower than at 24 h after last application. Tacrolimus concentration decreased with increasing skin depth. Systemic tacrolimus exposure after ointment application was low and highly variable, with 31% of samples below the limit of quantification (0·025 ng mL−1) and 94% below 1 ng mL−1. Blood concentrations at 24 h after the first and last ointment applications were 750 and 1800 times lower, respectively, than those in skin. Physicians’ assessments showed that tacrolimus ointment was effective and well tolerated. Conclusions  Tacrolimus was primarily partitioned in the skin, with minimal systemic absorption after topical application, in patients with atopic dermatitis.