Hii.. My Daughter Is 15 Years Old. She Has Thyroid

Hii.. my daughter is 15 years old. She has thyroid from last 3-4 years and now she has PCOS n over weight problem as well and also serum insulin test is 122.9 which quit high. Doctor prescribe her for Glycomet sr 500.if she take this medicine from this age,any side effects? ?i Is this medicine for diabetes? ? Her sugar level is normal. I am confused.. so please guide me for the same.