Hello Rehmawaqar, Thanks for posting. Myteka ( generic name montelukast) is primarily indicated for asthma (when corticosteroids or beta andregenic receptor medications are not effective) but could be used in situations of allergies (like in your case). Montelukast produces potentially life-threatening effects which include Angioedema. which are responsible for the discontinuation of Montelukast therapy. The symptomatic adverse reactions/side effects produced by Montelukast are more or less tolerable and if they become severe, they can be treated symptomatically, these include Headache, Drowsiness, Restlessness, Abdominal pain, Agitation, Oedema, Allergy anaphylaxis. For your drowsiness since the cause is the medication (if severe) you will have to stop and change to another antihistaminic drug with less side effects. So you can pay a visit to your doctor and present the issue. Hope this helps