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 The U.S. Centers for Disease Control and Prevention
estimates that 11 percent of American children between the ages of
four and 17 - or 6.4 million - had been diagnosed with ADHD as of
2011. About half were taking drugs to treat the disorder.
“We have too few long-term studies on the effects of these
medicines,” Dr. Sanford Newmark told Reuters Health. “There’s a big,
big gap in our understanding of what the effects of these medicines
might be. It’s worrisome.”
A pediatrician from the Osher Center for Integrative Medicine at the
University of California, San Francisco, Newmark was not involved in
the current study.
Researchers from the Mario Negri Institute for Pharmacological
Research in Milan, Italy, found a dearth of long-term studies on
side effects of stimulants such as Ritalin, which some kids take
into adulthood.
An extensive search revealed just six studies, all funded by
pharmaceutical companies, that followed a total of 3,000 children
treated with ADHD medications in clinical trials and examined
related side effects for at least 12 weeks.
“ADHD drugs seem to be safe and well tolerated according to the
available data, but more studies are needed,” lead author Dr.
Antonio Clavenna told Reuters Health in an email.
Decreased appetite, insomnia, headaches and stomach pain were the
most common side effects reported in the studies, the authors write
in the Archives of Disease in Childhood. Patients also experienced
tics and mood swings.
But the studies reported only common side effects and may have
missed unusual ones, like suicidal thinking and long-lasting
erections, that have concerned U.S. regulators, the authors write.
“In this regard, the safety profile of medications is not fully
understood, and monitoring is needed,” Clavenna said.
The Food and Drug Administration (FDA) in December issued a warning
that ADHD stimulants such as Ritalin and Concerta may in rare cases
cause prolonged and painful erections, some lasting so long they
might require surgery. In 2005, after short-term studies showed an
increased risk of suicidal thinking in children and adolescents, the
FDA ordered a black-box warning on atomoxetine, known as Strattera.
Kids diagnosed with ADHD tend to have trouble paying attention and
may have poor impulse control. Doctors frequently prescribe
medications to increase focus and reduce impulsivity.
Some children improve without prescription drugs with sleep and
dietary changes, behavioral therapy or extra help at school.
Newmark said he often sees children whose parents complain about
ADHD medication side effects not reported in studies.
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“One of the side effects they don’t talk about that I see all the
time is that these kids have personality changes,” he said. “Parents
say, ‘The medicine is working, but he’s just lost his spark,’ or,
‘She’s just lost her joy.’”
Hundreds of clinical studies have reported that most of the side
effects of drugs used to treat ADHD are mild and temporary, the
authors of the current study write.
In their review, the proportion of patients that stopped taking ADHD
medication, which ranged from 8 percent to 25 percent, was the only
adverse event measured in all six studies.
Most study participants who stopped taking the medication because of
side effects stopped in the first year.
Because the studies investigated different side effects, the authors
could not compare studies or treatment outcomes. They call the
reporting of side effects “unsatisfactory” and write, “more should
be done to improve the evaluation of drug safety.”
In 2011, Danish researchers, after reviewing short-term studies
examining adverse reactions to ADHD drugs, also called for long-term
safety studies. They pointed out that drug manufacturers funded
almost all of the studies, and a majority of the authors received
contributions from the pharmaceutical companies producing the
medications.
“The pharmaceutical company’s job is to sell their product,” Newmark
said.
“It is very important for us as doctors to base our practice not on
what the companies say but on objective evidence,” he said. “It’s
easier and cheaper for the pharmaceutical companies to do short-term
studies and say, ‘Look, the medicine works.’”
SOURCE: http://bit.ly/1pzJ82v Archives of Disease in Childhood,
online April 19, 2014.
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