N3 symptoms and conditions

I noticed a lot of postings about weight gain on Singulair, which is nowhere listed by Merck as a possible side effect. My 15 y.o. daughter experienced sudden weight gain at the age of 9 when she was actually underweight (BMI went from 17 to 21). To make a long story short, after being off Singulair for over a year, she is now over-weight, and diet/exercise have never made a big difference (gymnastics, swim team, figure skating, trampoline, etc.) Extensive labwork is always normal & there is no family history of obesity. It's a shame the quality of life of a child is RUINED by a drug that is deemed to have "no side effects", and the many drs. & specialists out there take it very lightly. We continually worry about our daughter's self-esteem, risk of diabetes, and other complications from weight gain which is not hereditary and goes on unexplained by the drug co. Reversing this weight gain has been nearly impossible. Everytime I hear a news report about our children being overweight and obese, it makes me angry because I think about the many kids that are taking this highly prescribed drug (for even the mildest allergy or asthma) and who knows how many parents don't make the connection!