Wednesday, November 7, 2012

Codeine For Kids? FDA Says Maybe Not

On August 15th, 2012, the FDA issued a Drug Safety Communication cautioning against the use of codeine in children following surgery. Four recent cases of severe adverse drug reactions prompted this communication.

In these cases doctors used the opioid narcotic codeine as a pain-killer following nose and throat surgery in children suffering from sleep apnea. Their ages ranged from 2-5 years old. All of the children received normal doses of codeine, however, respiratory symptoms developed within two days of starting the regimen. Three of the four cases proved fatal. 

Evidence suggests that all four children possessed the CYP2D6 Ultra-Rapid Metabolizer phenotype. Enzymes within the liver naturally convert codeine into morphine. However, in these particular cases the children’s livers would have converted the codeine more rapidly than expected, leading to dangerously high blood-morphine levels.

Recent studies have shown some aspects of opioid sensitivity (including decreased respiratory rate, sedation, and addiction risk) can be genetically inherited. It’s estimated that 7% of the population possess the aforementioned Ultra-Rapid Metabolizer phenotype, although its estimated to be as high as 29% of North African and Ethiopian populations.

Conversely, individual genetics may also cause opioids to be processed more slowly than expected. The FDA reminds readers that the only way to know if someone is an Ultra-Rapid Metabolizer is to do a genetic test that determines an individual’s CYP2D6 phenotype.

Codeine, along with other related opioids such as methadone and oxycodone, forms a cornerstone of advanced pain management, and is also used as a cough suppressant. Adverse reactions to codeine typically manifest as sleepiness, confusion, or breathing difficulty. Nausea is also common, affecting approximately one out of every three patients taking codeine post-surgery. Even non-serious side effects can be problematic, extending hospital stays and increasing likelihood of readmissions.

The FDA is currently investigating to determine if additional cases of severe adverse drug reactions have occurred in children. They advise healthcare professionals to be conservative in their prescribing regimens and remind parents to monitor their children’s health for any adverse drug reactions whenever taking new medications. □


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