商品名：Circadin
Hormone which is involved in the neuroendocrine control of seasonal hair loss.
Treatment of hair cycling disorders in dogs; in particular the treatment of alopecia X and seasonal flank alopecia. A 4–6 week trial is recommended, if no growth is noted then treatment should be discontinued. For seasonal flank alopecia, treatment may have to be repeated the following year. The effect of melatonin on hair re-growth in dogs with non-pruritic alopecia of unknown aetiology is variable and every effort should be made to identify the underlying disorder before starting this therapy.
劑量數字暫停提供：VetPro 的劑量改依 DRUGAPI 藥物資料庫對外的內容，DRUGAPI 目前不提供可直接計算的劑量。下方列出 DRUGAPI 的審查結論與劑量審查引用的來源；計算機可手動輸入劑量換算。
核對完整成品、釋放型態、全部賦形劑與複方成分、供應來源及當地法規。 獨立確認物種、性別、生殖狀態、診斷及需排除疾病，不套用其他診斷或物種研究。 建立個案反應與停用、監測、救援及追蹤計畫；誤食須評估整件製品而非僅有效成分。 獨立查核全部併用藥；未接受完整配對時一律未評估，不能由鄰藥覆寫。
依出現頻率分組；嚴重副作用獨立列出，臨床上需立即辨識。