title: Olopatadine hydrochloride suppresses the rebound phenomenon after discontinuation of treatment with a topical steroid in mice with chronic contact hypersensitivity.
abstract: BACKGROUND
  Olopatadine hydrochloride (olopatadine; Allelock) is one of the second-generation antihistamines that are treated for allergic disorders such as rhinitis, urticaria and eczema dermatitis. Olopatadine has recently been shown to have inhibitory effects on the chronic contact hypersensitivity induced by repeated application of oxazolone in mice. Although topical steroids have widely been prescribed for atopic dermatitis, a relapse often occurs within several days after discontinuation of their prolonged use.
  
  
  OBJECTIVE
  We investigated the possible efficacy of olopatadine against the relapse after discontinuation of prolonged use of topical prednisolone in the Balb/c mice with oxazolone-induced chronic contact hypersensitivity.
  
  
  METHODS
  Mice with the chronic contact hypersensitivity induced by repeated application of oxazolone were treated with olopatadine as a sequential therapeutic agent. The effects of olopatadine were quantified by measurements of ear-swelling, and levels of cytokines and histamine in the lesioned ear. Results Topical prednisolone (0.05 mg/ear/day) significantly inhibited the increases in ear swelling and production of IL-1beta, IL-4, IL-18, granulocyte-macrophage colony-stimulating factor (GM-CSF) and histamine. However, after discontinuation of the treatment with topical prednisolone, the inflammation relapsed and the IL-4 level exceeded the control one. The sequential treatment with olopatadine (10 mg/kg/day) after discontinuation of the treatment with topical prednisolone alone, or topical prednisolone with olopatadine, significantly inhibited the increases in ear swelling and levels of IL-1beta, IL-4, IL-18, GM-CSF, nerve growth factor and histamine.
  
  
  CONCLUSIONS
  These results indicate that olopatadine is an antihistamine agent having inhibitory activities against the rebound phenomenon following the discontinuation of topical steroid therapy. Olopatadine is thus expected to be a sequential therapeutic agent after discontinuation of the chronic treatment with a topical steroid.
authors.affiliation: Pharmaceutical Research Center, Kyowa Hakko Kogyo Co., Ltd, Shizuoka, Japan. tadafumi.tamura@kyowa.co.jp
authors.forename: T
authors.initials: T
authors.lastname: Tamura
authors.forename: M
authors.initials: M
authors.lastname: Matsubara
authors.forename: K
authors.initials: K
authors.lastname: Hasegawa
authors.forename: K
authors.initials: K
authors.lastname: Ohmori
authors.forename: A
authors.initials: A
authors.lastname: Karasawa
mesh_terms: D000818:Animals; D002908:Chronic Disease; D003877:Dermatitis, Contact / Q000188:drug therapy* / Q000276:immunology; D003990:Dibenzoxepins / Q000627:therapeutic use*; D005938:Glucocorticoids / Q000627:therapeutic use; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D015847:Interleukin-4 / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D023421:Models, Animal; D000069605:Olopatadine Hydrochloride; D011239:Prednisolone / Q000627:therapeutic use; D012008:Recurrence; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy*
chemical_list: D003990:Dibenzoxepins; D005938:Glucocorticoids; D006634:Histamine H1 Antagonists; D015847:Interleukin-4; D000069605:Olopatadine Hydrochloride; D011239:Prednisolone