Melatonin vs. placebo for prevention of delirium in hospital in people with advanced cancer

INTERVENTION: Melatonin prolonged release 2mg oral tablet nightly commenced within 48 hours after hospital admission and continued until delirium occurrence, discharge, or for a maximum of 3 weeks after any acute medical issues imparting a delirium risk have been resolved. The intervention will be delivered at 20:00 hours. At each dose, the individually labelled bottle will be opened and the prescribed dose taken out. The clinical nurse will observe the participant while the participant swallows the tablet whole, and then record the administration in the medicine record. CONDITION: Advanced Cancer Delirium PRIMARY OUTCOME: Number of delirium‐free days (which occur before delirium onset for any participant who develops delirium). ; For each participant, delirium screening will occur every 8 hours on each of the three 8‐hour shifts by the ward nurses, using the Nursing Delirium Screening Scale (NuDESC). Participants scoring 2 or higher in the NuDESC will be assessed with The Delirium Rating Scale – Revised 98 (DRS‐R‐98) to confirm delirium presence and delirium severity. SECONDARY OUTCOME: Delirium precipitating factors measured using the Delirium Etiology Checklist (DEC) Delirium profile assessed by DRS‐R‐98 (Delirium Rating Scale‐ Revised‐98) Family distress using the Delirium Experience Questionnaire In‐hospital complications: ; Falls, pneumonia, thromboembolism, pressure areas, changes in performance status (AKPS) and survival will be documented daily in the medical records until participant's hospital discharge and then weekly in the follow‐up period (21 days after ceasing study medication). Inpatient resource utilisation ; variables include duration of admission (days), daily medications, investigations (blood tests, imaging, urine cultures), and level of nursing required for transfers or care (independent, standby assistance, one or two assistants) and use of one to one nursing (hours). This information will be assessed by review of medical records. Regular and administration of ‘as required’ doses of benzodiazepine and antipsychotics will be recorded daily in the participant medication chart (within the medical record) ; Sleep quality measured using the Insomnia Severity Index Toxicity: ; ‐ Sedation: assessed by the Richmond Agitation‐Sedation Scale ‐ Palliative (RASS ‐ Pal) ; ‐ Days in coma defined as RASS ‐ Pal score of ‐4 or ‐5. ; ‐ Other adverse events: assessed using the National Cancer Institute Common Terminology Criteria INCLUSION CRITERIA: ‐ Aged 18 years or older ‐ English speaking or availability of a health care interpreter. ‐ Diagnosis of advanced cancer (histological or clinical diagnosis) defined by the intent of treatment no longer being curative ‐ Admission to an acute or sub‐acute inpatient facility ‐ Participant is able to give fully informed written consent