My husband born 12 2557 white Caucasian male active no known drug allergies recently prescribed Singulair for respiratory problems secondary to tobacco use. He is truly a saint, typically my calm, does not have an angry bone in his body and I have noticed extreme irritability agitation and difficulty waking is this normal I am concerned he does not notice the change however has been on it for two weeks maybe... I would appreciate it if you could just give me a straight answer rather than tell me to contact the physician or pharmacist. I tried that but my husband does not acknowledge the negative side effects if that is what they are just needing a little confirmation thank you in advance for your prompt answers and explanations! Happy holidays! Sorry for the grammatical errors very busy with Christmas approaching LOL