safe to stop medicine without weaning off

My daughter has been taking Singulair for almost 2 years now since suffering an asthma attack that landed her in the hospital for 2 days. I took her off last summer while she was home and away from school for about 2 months and she did fine without. However her doctors want her to be on it at least during the school year. I wanted to take her off again since she doesn't seem to have allergic asthma, she mostly wheezes when she get sick with a respiratory virus. Is it safe to take her off without weaning it since she's been on it for 2 years now?