Long-term safety is yet to be established.There is insufficient evidence at present to support treatment beyond 3 weeks or repeated use after an initial course.PBS listingMelatonin (Circadin) is not listed on the PBS.Place in therapyMelatonin is a hormone secreted by the pineal gland to regulate circadian rhythm and the sleep???wake cycle.1 A new prolonged-release melatonin tablet (Circadin) is TG