Codeine supplied OTC is a continuing issue for pharmacists. This year new rules were introduced to reduce the risk of addiction in pain relief, and in 2007 the MHRA issued a warning about the use of codeine-containing medicines in breastfeeding.
Now the MHRA has continued the codeine crackdown, advising linctus that contains codeine is not suitable for dry cough in those under 18 years.
The reasons for the decision seem to be legion, but high up on the list is the big question mark over whether the products work for this indication.
Recent evidence looking at codeine, pholcodine and dextromethorphan has been conflicting, with most trials rating the antitussives as little or no better than placebo. The MHRA puts the lack of efficacy at the top of its list of reasons for the advice, pointing out that dry coughs are generally self-limiting and rarely harmful.
Another key factor in the decision are safety concerns due to its central mode of action. Codeine is converted into morphine by the cytochrome P450 CYP2D6, but this has substantial variation of expression in individuals, which means different patients can get substantially different levels of morphine.
Finally, the MHRA expresses concern about accidental ingestion of OTC liquid codeine, and has advised all liquid codeine medicines should be packaged in child-resistant containers by June 2012.
Fortunately, the new recommendations should have little impact in immediate practice. Products containing dextromethorphan, the most widely used opioid in OTC cough remedies, are not affected by the advice – probably because of its lack of side effects compared with codeine (which can cause sedation, constipation and addiction).
The MHRA advises the affected products, such as Codeine Linctus BP, do not need to be removed from shelves. Instead, pharmacists are urged to consider the new advice when advising on cough medicines, and consider alternative treatments in households with children present.
While not enshrined in regulation, the advice seems to herald the end for codeine products in anything other than short-term pain relief.
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