MELATONIN

Day 1: #melatonin is derived from the pineal gland & was first isolated in the late 1950s. Named from observation of altered frog pigmentation, but the role for human melanin is unknown. Known for circadian rhythm & sleep promotion, but has diverse effects, including immunomodulation & bone remodelling

Day 2: #melatonin is licensed in adults to manage short-term insomnia & jet lag. One named tablet is licensed for use in children with ASD or Smith-Magenis Syndrome. Insomnia dose range 2-10mgs at bedtime. There is high demand for #melatonin to manage sleep issues related to childhood conditions such as ADHD, as well as from medicines which cause insomnia e.g methylphenidate. Many unlicensed ‘Specials’ options are available for children, which can also be high cost

Day 3: High oral absorption but high 1st pass metabolism leading to 15% bioavailability. Food increases absorption. High Vd. Rapid liver metabolism via CYP1A enzymes. Renal excretion. Short t½ 0.5-1hr (i.r). Avoid m.r if hepatic impairment; avoid i.r if mod-severe. Caution for m.r/i.r if renal impairment