Study finds Prozac may inhibit bone growth in children

A common class of drugs prescribed to children with depression may have an adverse effect on bone growth, according to a new study.

The study, published online Thursday by the journal Endocrinology, looked at the effects of fluoxetine, sold as Prozac, on bone growth in young mice. Researchers at the Indiana University School of Medicine in Bloomington wanted to look at Prozac because it is the only prescription antidepressant currently approved by the Food and Drug Administration for use in children and adolescents, aged 7 to 17.The drug is part of a class called selective serotonin-reuptake inhibitors, which have also come under scrutiny recently after a series of studies showed that youths taking them had twice the risk of suicide compared with those taking an inactive pill. The FDA last month ordered new warning labels about these drugs and other antidepressants that might be used by children and teens.The drugs work by increasing the level of the brain signaling chemical serotonin and have been shown to be extremely effective at treating depression in adults and many children.In the Indiana study, scientists found a reduction in both bone mass and size in young mice administered the drug compared to a control group.”These findings indicate a potential negative impact of SSRIs on the skeleton and point to a need for further research into the prescribing of these drugs to children and adolescents,” said Stuart Warden, an assistant professor of physical therapy and lead author of the study.The Indiana team noted that other research has connected SSRI use to increased bone loss at the hip in elderly women, to decreased bone density in men and to decreased skeletal growth in children.One of the clinical trials on children used to show the effectiveness and safety of the drug to the FDA found that youngsters treated with Prozac gained, on average, about a half inch less in height and two pounds less in weight after 19 weeks compared to a control group.Eli Lilly, the company that markets Prozac, agreed to do further studies after the drug went on the market for children to determine if there are any effects on long-term growth.The findings add to those concerns, but also underscore the complexity of treating teens and children for depression, which may affect as many as 10 percent of those 7 to 17.”Bone development early in life is believed to determine lifelong skeletal health,” Warden said. “Anything that affects normal bone development may have far-reaching consequences later in life when the skeleton is more prone to fracture.”Other studies done by the National Institute of Mental Health have found that, at least in middle-aged women, other brain chemicals associated with depression have the effect of weakening the bones and reducing bone mineral density if the depression is left untreated.There are other drugs that can help boost bone density that could help offset these effects. They already are given to some children who take other medications, such as steroids, that are known to affect bone growth.