Pharmacist prescribing of melatonin

Clinical
By
Karen Castle MPS
-
prescribing melatonin

Melatonin is a naturally occurring hormone responsible for regulating the body’s circadian rhythm. Secretion of melatonin declines during adulthood. Supplemental melatonin can help to reinforce the circadian rhythm, making it useful for treatment of insomnia and jet lag.1

How can pharmacists meet their legal and professional obligations when prescribing melatonin for insomnia?

When prescribing melatonin as a Pharmacist Only medicine, you must establish therapeutic need, determine the medicine is safe for the patient and comply with restrictions of the Schedule 3 listing. This includes that the patient is aged 55 or over and it is for short-term treatment. Routine recording of patient name, address and date of birth supports appropriate provision and is the best way for pharmacists to demonstrate they have met legal and professional obligations.

How long is ‘short-term’?

While there is evidence to support the safety and efficacy of melatonin up to 13 weeks,3 patients should be referred to a medical practitioner for review if they require treatment for more than 3 weeks.⁴ Three weeks is consistent with evidence from the pivotal efficacy study noted by the Therapeutic Goods Administration in the final decision to amend melatonin scheduling to Schedule 3.⁵

A patient who has been prescribed melatonin MR 2 mg nightly for 3 months by a medical practitioner presents to the pharmacy seeking a supply as they have run out. What can a pharmacist prescribe?

This pattern of use is not short term, so a pharmacist would not be able to prescribe melatonin within Schedule 3. Other options may apply, such as using emergency supply provisions relating to Schedule 4 medicines. The criteria for emergency supply by a pharmacist, and quantity of medicine able to be supplied, depends on the state or territory in which the pharmacist is practising.

What options are available to pharmacists to treat jet lag?

Despite the inclusion of immediate-release melatonin for jet lag in Schedule 3 of the Poisons Standard, at the time of writing, there is no commercially available immediate-release product in Australia which can be prescribed as a Pharmacist Only medicine. Pharmacists may compound an immediate-release preparation that contains 5 mg or less of melatonin when a particular person requests this medicine. If a commercial product becomes available, compounding would no longer be appropriate. Patients should be advised to avoid purchasing melatonin via the internet because the melatonin content may be unreliable.6 

Poisons Standard Schedule 3 entry for melatonin7

MELATONIN in:

(a) modified release tablets containing 2 mg or less of melatonin for monotherapy for the short-term treatment of primary insomnia characterised by poor quality of sleep for adults aged 55 or over, in packs containing not more than 30 tablets; or

(b) immediate release preparations containing 5 mg or less of melatonin for the treatment of jet lag in adults 18 years and over, in a primary pack containing no more than 10 dosage units.

References

  1. Goldstein, CA. Overview of circadian rhythm sleep-wake disorders. UpToDate [updated Dec 2023]. At: https://sso.uptodate.com/contents/overview-of-circadian-rhythm-sleep-wake-disorders?search=melatonin&source=search_result&selectedTitle=3%7E113&usage_type=default&display_rank=3 
  2. Insomnia in adults. Therapeutic guidelines [updated Mar 2021]. At: https://tgldcdp.tg.org.au/viewTopic?etgAccess=true&guidelinePage=Psychotropic&topicfile=insomnia-adults
  3. Treatment guidelines for pharmacists: insomnia. In: Sansom LN, ed. Australian pharmaceutical formulary and handbook. 26th edn. Canberra: Pharmaceutical Society of Australia; 2024.
  4. Therapeutic Goods Administration. Notice of final decision to amend the current Poisons Standard in relation to melatonin. 2020. At: www.tga.gov.au/resources/publication/scheduling-decisions-final/notice-final-decision-amend-current-poisons-standard-relation-melatonin
  5. Pharmacy Board of Australia. FAQ – For pharmacists on the compounding of medicines. At: www.pharmacyboard.gov.au/documents/default.aspx?record=WD15%2f16635&dbid=AP&chksum=rE0qmZcEafURzzXc3NBiuA%3d%3d
  6. Therapeutic Goods Administration. Notice of interim decision to amend (or not amend) the current Poisons Standard. 2023. At: www.tga.gov.au/sites/default/files/2023-10/notice-interim-decisions-amend-not-amend-the-current-poisons-standard.pdf
  7. Therapeutic Goods (Poisons Standard – June 2024) Instrument 2024. At: www.legislation.gov.au/F2024L00589/latest/text