It is time to stop prescribing codeine to children altogether, one of Canada’s leading pain researchers says.
“It’s hard to identify a reason codeine is still being used,” Allen Finley, director of the Centre for Pediatric Pain Research at IWK Health Centre in Halifax, said in an interview. “We should get rid of it.”
He was reacting to a study that showed that two children who had routine surgery, like tonsillectomy, have died recently after being prescribed codeine for post-surgical pain. The deaths have shocked many because Canadian researchers warned of this danger years before. Ingrained prescribing habits, and concerns – founded and unfounded – that other types of painkillers are more problematic, have been blamed for the slow response.
However, leaders in the field, such as the Hospital for Sick Children in Toronto, have stopped prescribing codeine altogether, and other institutions and individual physicians and surgeons are reviewing their practices.
Dr. Finley said about 5 per cent of children have a genetic variant that makes them metabolize the drug quickly and therefore susceptible to overdose. At the other end of the spectrum, about 10 per cent of children lack an enzyme that would allow them to metabolize codeine, meaning the drug provides no pain relief.
“If you came to Health Canada today with this new drug, codeine, it wouldn’t have a hope of being approved,” Dr. Finley said.
He added that codeine is still used mainly “because it’s been around a long time.” But there is also a perception among physicians that the alternatives are no better – morphine because it is considered too powerful, and non-steroidal anti-inflammatory drugs like ibuprofen because they increase bleeding, a particular concern after surgery.
“Physicians are doing what they were trained to do. We need to retrain them to not use codeine,” Dr. Finley said.
To date, the Hospital for Sick Children is the only institution to have removed codeine from its formulary. Many pediatric hospitals keep children overnight if they are prescribed codeine to monitor them for life-threatening reactions. The Canadian Paediatric Society is reviewing the guidelines on codeine use in children.
Benjamin Hoyt, an ear, nose and throat surgeon in Fredericton, said he stopped prescribing codeine last year after attending a scientific conference hosted by the Canadian Society of Otolaryngology where he heard of research showing morphine is safer and more effective.
“I’ve given up entirely on codeine in my pediatric patients. I prescribe morphine,” he said.
Dr. Hoyt said that when he writes a prescription for morphine “every parent’s eyes bug out of their head,” but once he explains, they understand.
The body converts codeine to morphine, so it is more effective to take morphine directly. Children with multiple copies of the allele CYP2D6 gene variant metabolize codeine so quickly that they get an overdose of morphine. That does not occur when morphine is prescribed in weight-appropriate doses.
“We have tended to underestimate codeine’s potential for harm because it’s been around so long,” said Michael Rieder, a professor of pediatrics and pharmacology at the University of Western Ontario in London, and co-author of the new study, published on Monday in the journal Pediatrics. That research detailed the cases of three children who suffered fatal and near fatal overdoses after being prescribed codeine.
Dr. Rieder noted that the number of children with multiple copies of the allele CYP2D6 varies significantly among ethnic groups: 40 per cent in those from North Africa, 12 per cent in those who originate from the Middle East, and less than 3 per cent in those of European background. Conversely, codeine is ineffective in about 10 per cent of children of European background, compared to about 2 per cent of Asians.
In European countries, prescribing codeine to children is virtually unheard of, Dr. Rieder noted. But, in Canada, codeine is still, after acetaminophen (brand name Tylenol), the most common painkiller prescribed to children post-surgery and in emergency departments.
He said that despite the study showing the deaths in children taking codeine, parents should not panic.
“Codeine is still a useful medication, but dosing and timing are key,” Dr. Rieder said.
He said it is important not to vilify codeine unduly but, rather, “parents, like physicians, need to understand that no drug is side-effect free. Potent drugs have potent side effects.”
Ruth Dubin, an assistant professor in the department of family medicine at Queen’s University in Kingston, said merely getting rid of the drug is not enough. Alternatives are needed.
“If we discard codeine, let’s be sure we have a workable backup plan,” she said.
Dr. Dubin’s worry is that, because of morphine’s poor reputation, children might end up inadequately treated for pain. “We might truly be throwing the baby out with the bathwater,” she said.
Dr. Finley agreed that treating children properly for pain is essential, and that is why he prefers morphine. He said common fears among physicians and patients that the drug is highly addictive and will be diverted for use by addicts are unfounded.
Tips for parents of young patients
What to do if your child is prescribed codeine:
“Personally, I would say: ‘I'm uncomfortable with this. I prefer a prescription for morphine,' “ says pediatric pain expert Allen Finley.
If your child has never had codeine before, give one dose and watch closely for reactions. Be alert to whether the child becomes overly drowsy or has trouble breathing; those are early signs of overdose. “If things don't seem right, go back to the hospital. That's what emergency is for,” says Dr. Michael Rieder, author of the study on the dangers of codeine.
But don't be too worried. Codeine is an effective painkiller for about 85 per cent of children. (The risks are greater for some ethnic groups, such as North Africans.)