Singulair Lawsuits: Neuropsychiatric Issues https://www.lezdotechmed.com/blog/mass-tort/singulair-lawsuits/ Several singulair lawsuits have been brought against the drug's maker, Merck & Co., due to the medication's severe mental health side effects. Millions of people take the asthma and allergy medication singulair, but in recent years, it has also been linked to mental health problems, including suicide thoughts. singulairlawsuits