For the second time in as many months, Canadian doctors will be warned that a widely used anti-depressant has been linked with a possible increased risk of suicidal thinking in children.
Wyeth Pharmaceuticals is preparing to send letters to about 40,000 doctors warning them that recent studies have found increased reports of hostility and suicide-related “adverse events,” such as thinking about suicide and possibly self-harm, among children and teens taking its drug Effexor XR.
The alert follows a similar letter issued to U.S. doctors in late August that advised physicians to watch for “signs of suicidal ideation in children and adolescent patients prescribed Effexor” or Effexor XR, the extended-release version of the drug.
In July, GlaxoSmithKline warned doctors that its top-selling anti-depressant Paxil should not be given to children under 18 “due to concerns of a possible increased risk of suicidal thinking, suicide attempts or self-harm.”
Neither drug has been approved in Canada for use in anyone under 18. But these and other psychiatric drugs designed for adults are being prescribed “off label” to children and teens, despite sparse evidence, critics say, that the drugs are safe or effective in youth. Off label allows doctors to prescribe drugs for situations not expressly covered in the approval process.
The back-to-back warnings come as studies suggest the number of children on psychiatric drugs is soaring. A report published this year in the Archives of Pediatrics and Adolescent Medicine found that the proportion of children and teens in the U.S. swallowing stimulants such as Ritalin, antidepressants or other psychiatric medications more than doubled from 1987 to 1996.
In Canada, “lots of children and adolescents” as young as six to eight have received anti-depressants known as SSRIs, or selective serotonin reuptake inhibitors, a class that includes Paxil, says Dr. Robert Milin, clinical director of the Regional Children’s Mental Health Centre at the Royal Ottawa Hospital. With too few drugs officially approved for children, doctors are forced to prescribe medicines tested only on adults, he says.
But adolescence is the peak age of onset for major psychiatric disorders, Dr. Milin says. “Are you going to leave these patients untreated in terms of not receiving what may be appropriate medication and simply let them continue in their depression?”
In its letter to U.S. physicians, Wyeth reports that, in clinical studies involving children and teens ages six to 17, two per cent of those who were being treated with Effexor XR for major depression reported suicidal thoughts, compared to none who were taking a placebo, or sugar pill. In another study, one per cent of children who were taking the drug for a generalized anxiety disorder reported “abnormal/changed behavior,” compared to zero in the placebo group.
Wyeth, which is updating its prescribing information, says doctors “may need to reassess the benefit-risk balance” when treating patients with Effexor. They warn that if the decision is made to stop the drug, it shouldn’t be halted abruptly because of the risk of “discontinuation symptoms,” which, according to the drug information, can in adults include headaches, dizziness, insomnia, nervousness and nightmares.
More than 2.7 million prescriptions were dispensed for Effexor XR in Canada last year, according to IMS Health, which tracks prescription drug use in Canada.
More than 3.4 million prescriptions for Paxil were dispensed in Canada last year, according to IMS Health. A spokeswoman for GlaxoSmithKline says the company believes only a “small fraction” were for children.