What are the side effects of Singulair?

These are potential side effects meaning you may some of the common ones or none at all.

Singulair side effects
Get emergency medical help if you have signs of an allergic reaction to Singulair: hives, blisters, severe itching; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your doctor right away if you have signs of blood vessel inflammation: flu-like symptoms, severe sinus pain, a skin rash, numbness or a "pins and needles" feeling in your arms or legs.

Some people using Singulair have had new or worsening mental problems. Stop taking this medicine and call your doctor right away if you have unusual changes in mood or behavior, such as:

agitation, aggression, feeling restless or irritable;

anxiety, depression, confusion, problems with memory or attention;

stuttering, tremors, uncontrolled muscle movements;

suicidal thoughts or actions;

hallucinations, sleep problems, vivid, dreams, sleep-walking; or

compulsive or repetitive behaviors.

Common Singulair side effects may include:

stomach pain, diarrhea;

fever or other flu symptoms;

ear pain or full feeling, trouble hearing;

headache; or

cold symptoms such as runny or stuffy nose, sinus pain, cough, sore throat.

Source: Drugs.com