Opioid pain killers are far more addictive than previously thought and doctors are being urged to assess their patients' level of risk before writing a prescription.
The issue is whether opioid treatment is going to make an addict out of someone, says Professor Jane Ballantyne, a pain specialist at the University of Washington.
"A lot of people who get into trouble with opioids say the whole thing started when they were prescribed opioids for acute pain," she told an Australian and New Zealand College of Anaesthetists (ANZCA) conference in Singapore on Tuesday.
Opioids are safest when administered in hospital. However, it is common for codeine and oxycodone to be prescribed for out-patients after surgery, dental treatment or injuries.
"We used to say people would not become addicted, but unfortunately that's not true," said Professor Ballantyne. Although only a minority of patients develop problems, it is essential for doctors to do a quick risk assessment for every patient.
This could be done in five minutes with just four questions, she said. Those most at risk include people with any history of substance abuse, including smoking. People with mental health issues like depression, anxiety and personality disorders are also vulnerable.
A big challenge is for doctors to determine the motives of a person who is already dependant. They could be seeking pain relief or need to relieve the symptoms of drug withdrawal.
Some patients go from doctor to doctor in search of prescriptions, often to sell the drugs for a profit. "My patients have in the past been caught outside the hospital selling their drugs," Prof Ballantyne said.
"Most states in the US now have a way of monitoring every prescription that is written. So it is becoming a habit, especially in the emergency room to look at patients records."