http://www.medications.com/effect/view/29169 My daughter has been on singulair since age 3. I can't believe all the side affects that other children are having on the medicine to. This answers so many questions for me. We have been battling with leg cramps,stomache pain,bedwetting and weight gain. Wed, 09 Apr 2008 12:10:00 -0400 http://www.medications.com/effect/view/29169?item=6904 I noticed a lot of postings about weight gain on Singulair. How old is your daughter now? My daughter (now 15) was 9 when she gained 20 lbs in 6 mo. along with the leg and stomach pains, and continued to gain more while being active. She's been off Singula http://www.medications.com/effect/view/29169?item=6904