A recent study found that metformin led to a small drop in children's weight over the short-term.
Metformin is known by the brand names Glucophage, Fortamet, Glumetza and Riomet.
The decrease was evident when the medication was paired with lifestyle interventions, such as diet changes and exercise.
It did not appear that metformin was a significantly better option than other weight loss methods, though, the researchers wrote.
"Discuss your child's weight loss options with a pediatrician."
This study, led by Marian S. McDonagh, PharmD, looked at the effectiveness of the medication metformin for treating obesity in children.
The researchers looked for all clinical trials published on metformin in children that provided data on children's body mass index at the end of the study.
Body mass index (BMI) is a ratio of a person's height to weight and is used to determine if a person is a healthy weight or not. In adults, a BMI between 18.5 and 25 is considered healthy and normal. A BMI between 25 and 30 is overweight, while a BMI over 35 is obese.
However, these BMI categories do not always apply to children. In children, normal, overweight or obese BMI categories are determined based on a child's age and height.
The researchers found 14 randomized clinical trials that met their requirements.
Together, these studies showed that non-diabetic children taking metformin lost an average 1.38 BMI points compared to children not taking metformin after six months.
Studies lasting shorter than six months also showed a small effect.
However, studies that lasted one year did not show a reduction in BMI points that was large enough to attribute to the medication (instead of possibly being due to chance differences).
When the researchers looked at children who started the study with a BMI below 35, they found a smaller drop in BMI, but it was not due to chance.
This same pattern was found among Hispanic children, older teens and children who had tried and failed at diet and exercise programs.
The researchers also looked at the safety of metformin for children.
They found that 26 percent of the children taking the medication experienced some kind of gastrointestinal problem, compared to 13 percent of children who did not take the medication.
No serious side effects were reported, and no more of the children taking metformin stopped taking the medications than children taking the placebos (fake medications).
The researchers therefore concluded that metformin did lead to a small drop in BMI in children when combined with lifestyle changes over a short-term period.
However, "In the context of other options for treating childhood obesity, metformin has not been shown to be clinically superior," they wrote.
Andre Hall, MD, an OBGYN at Birth and Women's Care, PA in Fayetteville, NC, explained that metformin is most commonly used as an oral alternative to insulin in diabetic patients but has also been used in treating women with polycystic ovarian syndrome.
"Metformin helps decrease weight in these patients, thereby addressing the overall condition," he said. "It makes sense, therefore, that this would be a safe alternative to treating childhood obesity."
Dr. Hall emphasized the importance of treating obesity early on but recognizing what all aspects of that treatment should include.
"Obese children become obese adults and therefore it is important to address this problem when people are children and their lifestyles can be readily influenced by the adults responsible for their care," he said.
"Regardless of which medication is chosen to assist with the weight loss, the pillars of treatment must remain a healthy diet with reasonable caloric intakes along with regular exercise," he said.
This study was published December 16 in the journal JAMA Pediatrics. Information on funding was not provided. The authors declared no conflicts of interest.