I am a 57 year old man, who has been suffering from asthma severa...

i think that sympton is in line with the churg something syndrome read all of the singulair side effects postings you will see this drug is pure poisen gl to you

I also am 56, have been taking Singular off and on for about 4 years. I never took it longer than a few weeks at a time, just when my allergies and asthma would worsen during hay fever or during the winter. I always felt it made me more prone to sinus infections if I took it routinely. Recently though my job
changed and I was working really long hours and started taking it routinely just to control my allergies so I could function better at my job. After taking it routinely for over a month I noticed numbness in both arms and hands and a feeling of vibration when I touched things. I thought maybe I had a pinched nerve or my new work station had placed me in a physical position which was causing some sort of nerve impingement. Then I heard about the Singular problems on the news and stopped taking my Singular.
I am super congested nasally but my numbness has cleared up and I also noticed I was feeling better emotionally. I hadn't even realized how down I had been, I was attributing my fatigue and "blueness", crying jags etc. on my job and the stress it was causing. Once off the Singular, even though this job has not changed at all I am feeling much more optimistic about everything. It has really been an eye opener for me. Now I just need to find something to clear up the nasal congestion that doesn't do something else to me! For those of you that are unsure about Singular causing your problems, try decreasing the dose slowly until you can get off of it for at least a week and see if things don't start improving. Of course talk to your doctor about doing this but there are other medications out there, don't feel you are trapped into taking this one and putting up with side effects that really affect your life. Best Wishes.

from the UK:

Yellow Card reports: urticaria, angioedema, blistering, bruising, bleeding disorders, including menorrhagia (rare), thrombocytopenia and agranulocytosis (both very rare).

Churg-Strauss syndrome Churg-Strauss syndrome (CSS) is a rare syndrome characterised by a history of asthma, and often rhinitis and sinusitis, with systemic vasculitis and eosinophilia. There has been a recent increase in the number of reports of CSS associated with the use of anti-asthma drugs, particularly the leukotriene receptor antagonists. The MHRA/CSM have received 63 reports of CSS through the Yellow Card Scheme since 1963, 59 since the beginning of 1998; Of these, 90% were associated with drugs used to treat asthma (mainly leukotriene receptor antagonists). In many, but not all cases there was documented evidence of a reduction or withdrawal of oral corticosteroid therapy prior to the onset of the reaction. There are clear warnings regarding the possible association with CSS in the product information for montelukast and zafirlukast. Prescribers should be aware of the possibility that, although rare, CSS may be the underlying cause of asthma in their patients.
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See here:

In patients prescribed a leukotriene receptor antagonist prescribers should be alert to the development of eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications and/or peripheral neuropathy.
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The identification of new and suspected ADRs emphasises the important role of the Yellow Card Scheme in helping to ensure the safe use of medicines. The safety profile of leukotriene receptor antagonists remains under close review.

I had major allergy problems that I thought was a sinus infection. Upon going to the hospital they prescribed me Singular. I took this medication on Friday afternoon and have not slept a wink since then. It is now Monday and I feel like I'm on crack. (not that i know what that feels like but you get the idea) My heart was racing so fast last night that I almost went back to the hospital. I am a 34 year old male, deffinatey out of the child years, this and most allergy medicines do something similar. Also, I noticed while on the singualr I developed a chest issue where it hurts and feels dried out and a caugh that I didn't have before taking this medication. That is awesome if this is working for some people but for me this is the bar none worst experience I have ever had taking any prescriptions and I would urge folks that they take this med as a last resort. I can deffinately see how this causes mood swings because if I took even one more pill and was up for the next 2 days.....yeah I would be having some mood swings

When I was 47 I had a problem with dizziness due to what was diagnosed as a severe sinus infection, my doctor prescribed Singulair. I took it for about ten days in which I noticed a change in sleep patterns right away. I didn’t have problems falling asleep, but when I’d wake up in the mornings I never really felt rested. It was as if I had not slept at all! From night one I would have extremely vivid weird dreams. The dreams were so vivid I wondered if I wasn’t actually sleep waking or something. Anyway these dreams came every night, and during the day I began feeling agitated by the minor of things to the point where I was experiencing aggressive thoughts and actually had thoughts of acting these things out. I was constantly grouchy and temperamental and additionally started feeling muscle weakness in my legs and arms, tingling in my hands and face and pain in my finger joints. Since I had not had these problems before the Singulair, I told my doctor what I was experiencing; of course she blew me off and recommended I take antidepressants. I decided after that to discontinue the Singular and the doctor. Never felt better.