Codeine painkillers may be unsafe

Experts are calling for a review on the use of codeine in any medication – and even a possible ban – following growing concern over its safety.

They say that over-the-counter painkillers and cough mixtures containing codeine used by millions may be unsafe, addictive, ineffective, and should not be used by children.

Some 27million packs of codeine-containing painkillers are sold over the counter each year in the UK alone, with brands including Nurofen Plus, Solpadeine Max, Panadol Ultra and Syndol.

Codeine is a narcotic which makes users feel relaxed. Tens of thousands are thought to be hooked on over-the-counter medication containing it, with some taking 70 tablets a day.

Many of the safety concerns surround the unpredictability of the way the body handles codeine, which has no effect on pain until it is broken down by the liver to produce morphine.

Growing concern about codeine, which has been used as a painkiller for about 200 years, has emerged from recent DNA studies showing that people with different genetic make-ups respond very differently to the opiod drug, which is inactive until it is broken down inside the body into highly addictive morphine.

Codeine

The variability of people’s response to painkillers containing codeine, combined with its potentially addictive nature when taken regularly, led Professor Noni MacDonald of Dalhousie University in Halifax, Nova Scotia, and Professor Stuart MacLeod of the University of British Columbia in Vancouver, to ask whether the time has come to phase out the drug completely.

In an explosive editorial published in the current issue of the journal of the Canadian Medical Association, MacDonald and MacLeod said that the public perception of codeine as a safe drug is fostered by its widespread availability in many over-the-counter painkillers, sold in Britain as well-known brands such as Nurofen Plus, Solpadine Max and Panadol Ultra as well as generic products.

“However, recent advances in our understanding of pharmacogenetics raise serious concerns about the safety of codeine, including emerging evidence that the narcotic can cause death even at conventional doses. Has the time come to phase out codeine altogether?” they asked.

Scientists have already identified some genetic factors that significantly affect the rate at which codeine is broken down into morphine by the liver. These genetic factors vary within the general population, making the response to codeine highly unpredictable from one person to the next, MacDonald and MacLeod said. “All of these genetic variations can have potentially serious clinical consequences. The wrong combination can result in toxic levels of morphine, even at conventional doses of codeine. For infants and young children in particular, this can be deadly because age appears to be a key factor in susceptibility to adverse effects of morphine,” they said.

“Clearly, pre-testing all patients for genetic variants before recommending codeine would be expensive and impractical. A more logical solution might be to restrict access to codeine for infants and young children, the apparent highest risk group,” they added.