The short answer
Melatonin may add to hydromorphone-related drowsiness or impairment. The concern is reasonable, but an exact added respiratory-depression risk has not been measured.
What this answer covers
Oral melatonin; dose, release form and product content vary.
- Supplement or preparation
- Melatonin
- Medication ingredient
- hydromorphone
Melatonin can impair daytime performance
A small placebo-controlled study found impaired reaction and tracking performance after daytime melatonin. This supports its potential to affect alertness, but did not test hydromorphone.
The opioid risk is established
Hydromorphone can cause sedation and dangerous respiratory depression. Its label warns that other CNS depressants can add to these effects, especially with other sedating medicines or alcohol.
Timing and release form matter
Immediate- and prolonged-release melatonin and different doses may affect alertness differently. The evidence does not establish a safe gap from hydromorphone or prove that bedtime use removes next-day risk.
Review the combination before adding it
Discuss the actual supplement with the prescriber and avoid driving when impaired. Slow or difficult breathing or being unusually hard to wake requires emergency help. Do not self-adjust hydromorphone or rely on a short supplement gap.
Evidence and practical considerations
Side effects & toxicity
Conditional additive-sedation precaution from exact hydromorphone label plus supplement guidance/independent effects; no pair incidence or proven respiratory-depression magnitude.
- Exact scope
- Oral melatonin; dose, release form and product content vary. with Hydromorphone RxCUI3423 IN; HCl oral immediate-release, extended-release and injected products distinguished.
- Medication form and route
- oral medication; intravenous medication; intramuscular medication; subcutaneous medication; oral supplement
What remains uncertain
- No unmeasured pair incidence, blanket class transfer or arbitrary spacing interval.
Factors that may matter: Preparation; Dose; Other medicines; Organ function.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed hydromorphone
Opioid respiratory depression and additive CNS-depressant risk; general serotonergic-drug warning. Constipation can be severe. Hydromorphone is extensively glucuronidated.
How this applies: Exact hydromorphone RxCUI 3423 IN, with stated salt/formulation/route bridge.
No supplement-specific incidence. Oral, injected and extended-release products differ; oral cannabinoid experiments cannot establish every route or formulation.
Source 2: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed hydromorphone
Opioid respiratory depression and additive CNS-depressant risk; general serotonergic-drug warning. Constipation can be severe. Hydromorphone is extensively glucuronidated.
How this applies: Exact hydromorphone RxCUI 3423 IN, with stated salt/formulation/route bridge.
No supplement-specific incidence. Oral, injected and extended-release products differ; oral cannabinoid experiments cannot establish every route or formulation.
Source 3: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed hydromorphone
Opioid respiratory depression and additive CNS-depressant risk; general serotonergic-drug warning. Constipation can be severe. Hydromorphone is extensively glucuronidated.
How this applies: Exact hydromorphone RxCUI 3423 IN, with stated salt/formulation/route bridge.
No supplement-specific incidence. Oral, injected and extended-release products differ; oral cannabinoid experiments cannot establish every route or formulation.
Source 4: federal supplement safety guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: Users of the specified supplement.
Daytime drowsiness can occur; people with epilepsy need medical supervision when using melatonin.
How this applies: Original source interpreted for hydromorphone only within the stated preparation and endpoint limits.
Not a direct hydromorphone combination trial; original preparation, dose and endpoint limits apply. No exact-pair adverse-event rate or protective spacing established.
Source 5: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 16 healthy young adults.
Reaction, response and tracking performance worsened after daytime melatonin.
How this applies: No opioid co-use; midday dose and healthy participants do not quantify hydromorphone sedation or respiratory effects.
No opioid co-use; midday dose and healthy participants do not quantify hydromorphone sedation or respiratory effects.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared exact hydromorphone article with formulation-specific evidence and uncertainty. | |
| Research summary published |
Article revision: 8219b7b99c054a72
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.