Why Would Singulair Cause Insomnia?

Singulair, montelukast, is a drug used for the prevention of asthma attacks, treatment of bronchoconstriction caused by exercise and to relieve symptoms of allergic rhinitis.

Inflammation in the airways is caused in part by leukotrienes, which are a chemical component of the body's immune system. Singulair works by modifying or partially suppressing the leukotrienes and thus reducing inflammation.

Singulair has been reported to cause insomnia in some people.

Function

• Singulair granules may be mixed with formula.

  Because of its specific mode of action, Singulair may be taken with some other allergy medications, but it is not useful for the treatment of acute asthmatic attacks.

  Singulair is available as a film-coated tablet and a chewable tablet. For babies over 6 months of age, it is available as granules, which may be mixed with formula, breast milk, apple sauce, carrots, rice or ice cream only.

Side Effects

• Singulair can cause a runny nose.

  As with all drugs, Singular can cause unwanted side effects. The Rx List website lists the following most common side effects: upper respiratory infection; fever; headache; pharyngitis, inflammation and soreness at the back of the throat; cough; abdominal pain; diarrhea; otitis media, ear infection; influenza; rhinorrhea, runny nose; and sinusitis. If used under medical supervision, montelukast has a low risk of long-term or serious side effects.

Neuropsychiatric Effects

• Singulair can cause isomnia.

  Although not identified in clinical trials, post-marketing reports by a small number of patients and prescribers have identified that Singulair is less commonly associated with some neuropsychiatric side effects. The U.S. Food and Drug Administration reports that these include agitation, depression, nightmares, hallucinations and insomnia. Merck now includes this information on their safety profile for Singulair

Considerations

• These effects are not simply confined to Singulair, but can occur to a greater or lesser degree in other montelukast preparations, including Accolate , Zyflo and Zyflo CR.

  Merck acknowledged that the "clinical details of some post-marketing reports involving (Singulair) appear consistent with a drug-induced effect."

Theories/Speculation

• Although insomnia is recognized as a potential side effect of Singulair, as of June 2010, no publicly available research that directly investigates the reasons for this has been published .

  In December 2003, the Neuroscience Technical Bulletin reported a link between trace amines (brain chemicals) and neuropsychiatric disorders.

  Merck's information leaflet informs patients that Singulair chewable tablets contain aspartame, a source of the trace amine phenylalanine, which is a brain stimulant.

  The Diet and Nutrition website reports that phenylalanine can cause insomnia.

Summary

• All drugs are tested and licensed before being offered to the public, but on occasion adverse side effects are not noted in pre-clinical trials and only become evident during marketing. These effects are reported to the FDA and the manufacturers that generally undertake research to identify the cause.

  To date, no such research is available in the public domain about Singulair and insomnia, so the cause cannot be definitively stated.