CURING DISEASE WITHOUT CREATING DISABILITY

Surgery to remove a child's tonsils to treat sleep apnea, a toddler was cranky and given a prescription for codeine syrup.  The mother measured out the exact dose of the syrup prescribed by her doctor (to repeat it every six hours).  A fever and wheezing developed.  On the second night following surgery his mother noticed his face looked pale.  She called 9-1-1 but the paramedics could not revive him.  An autopsy showed the child had toxic levels of morphine in his blood.  The New England Journal of Medicine, Canadian drug researchers revealed the toddler had extra copies of a gene that converts codeine into morphine.  It is not just the drugs prescribe to children that can harm them.  Like almost half the new mothers in Canada, a Toronto mother was prescribed Tylenol No. 3 (with codeine) after giving birth to her son.  Twelve days later he died of a morphine overdose.  These adverse drug reactions (ADRs) are a popular pain reliever. More than 2,500 Canadian children die from them each year and many more develop permanent disabilities such as heart damage and loss of hearing.

  Some other examples: life-threatening skin reactions to ibuprofen, anaphylactic reactions to antibiotics and destruction of bone tissue from corticosteroids.  “Young children are particularly vulnerable because they cannot express a response to a medication,” says Bruce Carlton, a clinical pharmacologist at B.C. Children’s Hospital in Vancouver.  “Over 75 percent of drugs used to treat children have never been tested for safety in children,” he concluded.  Carlton’s concerns led him to set up the Canadian Pharmacogecomic Network for drug Safety (CPNDS) with University of British Columbia geneticist Michael Hayden to track and investigate ADRs in children.  The network operates in 13 children’s hospitals from coast to coast.  Carleton, also a senior clinician at Vancouver Child and Family Research Institute, estimates that half of ADRs in children results from differences in genetic makeup that cause some children to break down certain drugs differently.  The FDA in United States and Health Canada have issued warnings that breast-feeding mom’s who take codeine should watch their babies for shallow breathing, limpness, unusual sleepiness and other signs of morphine overdose.  Regulators also required drug manufacturers to change the labeling to highlight the potential risk to children.  The network is doing a study to test the benefits of a predictive DNA saliva test.  Three hundred Ontario mothers will take it.  Ultrarapid metabolizers will be given a pain reliever other than codeine, such as ibuprofen.