I am an asthmatic and have been on Singulair for a long time now. I am aware that weight gain has not been cited as an adverse effect of this drug but I find that I have put on twenty pounds ever since I began having this drug. The other drugs that I am using apart from Singulair are Albuterol and Zyrtec. I really do not know what could be causing this weight gain and would really like to the bottom of the matter. I would like to know whether anybody has been in the same boat as mine after using Singulair and if so, what is the alternative to it? Please do get in touch with me and if you can, help me as soon as possible as I am really despondent due to this sudden weight gain and am at my wits end not knowing what to do about it.