Melatonin Receptor Agonist

Melatonin

Brand names: Circadin (2 mg PR), Slenyto (paediatric)

Melatonin is a hormone used as a short-term treatment for insomnia (especially in adults over 55), for jet lag, and under specialist guidance for sleep problems in some children with neurodevelopmental conditions.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is the natural sleep-regulating hormone; supplementing it helps reset or reinforce the sleep-wake cycle.

Prescribing in practice

It is generally used short-term for primary insomnia; address sleep hygiene and underlying causes.
Next-day drowsiness can occur; modified-release brands are not interchangeable.
It is metabolised by CYP1A2, so smoking and some drugs (e.g. fluvoxamine) alter levels.

Monitoring

Review sleep benefit and the ongoing need.

Counselling the patient

Take it a short time before bed as directed.
It can cause next-day drowsiness — take care driving.
Continue good sleep habits.

Evidence & guidelines

A short-term option for insomnia (notably in adults over 55) and used under specialist guidance for sleep problems in some children with neurodevelopmental conditions.

Reference: NICE TA739 (Slenyto); MHRA SPC Circadin; Herxheimer & Petrie Cochrane Review 2002 (jet lag); ESC/ERS Sleep Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways