Opioids are effective medicines for severe pain following surgery, but prolonged use is associated with risks such as dependence and overdose. In his thesis, Claes Gedda at the Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, investigated how common it is for patients in Sweden to continue using opioids after surgery, which patients are at higher risk, and whether usage following major surgery can be reduced.

The largest study included 1,245,211 adults who underwent surgery in Sweden between 2018 and 2022 and who had not collected opioids for most of the year prior to their operation. Of these, 35,132 people, or 2.82 per cent, continued to collect opioids both during the first three months and during months four to six after surgery.

”This corresponds to around 7,000 patients per year in Sweden who collect opioids long after they should have recovered from surgery”, says Claes Gedda.

The risk was higher, for example, among older people and those with greater comorbidity, a recent cancer diagnosis, chronic pain, anxiety or depression, as well as alcohol or drug problems. Emergency surgery was also linked to a higher risk. Patients who collected opioids during the first week after surgery were more than twice as likely to still be collecting them several months later.

“Our results show that part of the risk can be identified even before surgery. At the same time, post-operative prescribing is a factor that the healthcare system can actually influence,” says Claes Gedda.

In a study of 842 patients who underwent major colon and rectal surgery, an approach was used whereby opioids were administered on an as-needed basis rather than according to a fixed schedule, alongside other pain-relieving medicines. Over a four-year period, the median consumption of opioids fell by 70 per cent and, towards the end of the study, almost one in three patients received no opioids at all during the first six days after surgery.

”This shows that it is possible to reduce the amount of opioids used after surgery. However, we do not yet know whether reduced early use also reduces the risk of long-term use. This needs to be investigated further,” says Claes Gedda.

The doctoral thesis was supervised by Mattias Soop at the Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet. The public defence will take place on 4 December 2026.