It's time to phase out codeine, researchers urge

Although codeine has been used for pain relief for more than 200 years, it has never been subjected to the rigorous regulatory and safety requirements applied to all new drugs and its pharmacokinetics are unpredictable. Genetic variations in patients can mean very different responses to codeine, some with serious consequences. Infants and children are particularly vulnerable, and there have been several deaths due to different genetic responses. Serious, life-threatening effects have also been reported in adults.

"Because the need for oral pain control is so pervasive, the potential risk associated with codeine must be mitigated," write pediatricians Drs. Noni MacDonald, Section Editor, Public Health, CMAJ and Dr. Stuart MacLeod, University of British Columbia.

While limiting use of codeine, with minimum ages for codeine-based treatment, is one option, it is not ideal. Genetic testing prior to codeine use is expensive and impractical.

"Perhaps a more direct approach is now needed: to stop using the prodrug codeine altogether and instead use its active metabolite, morphine. Not only is the metabolism of morphine more predictable than that of codeine, but also it is cheaper," they write. They call for a warning to physicians and modifications to existing guidelines for codeine use and research to define safety parameters.