What happens to opioid painkillers patients don't use?
A Canadian study highlights how frequently unused opioid tablets remain in homes after emergency treatment.
Strong painkillers can be useful for short-term severe pain after an injury or emergency attendance. But tablets that are no longer needed may remain at home for months. A prospective Canadian study investigated how people stored and disposed of opioid medication prescribed when they left an emergency department.
How was the study conducted?
Researchers recruited adults discharged with an opioid prescription for acute pain and followed them by telephone at two weeks and three months. Of 2,590 who agreed to participate, 2,047 completed the two-week follow-up and 1,835 completed the three-month follow-up. Different questions had different numbers of responses, so the percentages below use the relevant respondents rather than everyone initially enrolled.
What did they find?
Two weeks after discharge, 84% of 1,811 respondents reported unused opioids at home. Among 1,525 answering the storage question, just 6.7% kept the medicines locked away; 25.8% reported keeping them out of reach of children or teenagers.
At three months, 61.9% of 1,495 respondents who had filled their prescription and were no longer using opioids still had tablets at home. Of those retaining them, 57.7% kept them in case of future pain, while 28.3% had forgotten or lacked time to return them. Only around one-third said they would voluntarily return unused opioids to a pharmacy if asked.
What are the limitations?
This was an observational study based on self-reported behaviour, which may be affected by inaccurate recall or socially desirable answers. Some people were not recruited or were lost to follow-up. Most participants were in Québec, where prescribing and medicine-return arrangements may differ from those in the UK. Crucially, the study did not demonstrate that unused tablets caused addiction, accidental ingestion or overdose.
What should patients do?
Take opioid medication only as prescribed, never share it and keep it securely stored, ideally in a locked place. When it is no longer needed, return unused medication to a UK community pharmacy for safe disposal; do not put it in household rubbish or flush it away. Safe prescribing matters, but so does what happens after the pain has improved.
Original research
JAMA Network Open, 20 October 2026. Read the original research.
This information is educational and does not replace individual medical advice.