Who Owns Singulair?

Singulair operates under Organon's corporate sustainability framework. As a prescription medication, its ethical considerations center on patient safety, regulatory compliance, and appropriate marketing.

FDA Regulatory Compliance: Singulair is subject to FDA regulation as a prescription drug. The 2020 boxed warning for neuropsychiatric side effects represents a significant regulatory action. Organon must comply with FDA requirements for warning labels, adverse event reporting, and post-marketing surveillance.

Patient Safety: The neuropsychiatric side effects associated with Singulair have raised significant patient safety concerns. The FDA's 2020 boxed warning and 2024 research findings have led to increased scrutiny of the drug's risk-benefit profile, particularly for patients with mild symptoms who may have alternative treatment options.

Manufacturing Standards: Singulair manufacturing facilities in the United States, Belgium, Germany, and Ireland must comply with FDA and international pharmaceutical manufacturing standards (cGMP). Organon inherited these manufacturing operations from Merck as part of the 2021 spinoff.

Drug Access: As a generic montelukast is available since 2012, patient access to affordable treatment is less of a concern than for patented drugs. However, the branded Singulair product continues to be marketed in markets where generic penetration is slower.

For more details, see Organon's corporate responsibility report.

Singulair has received recognition for its therapeutic innovation in asthma and allergy treatment, though its reputation has been significantly affected by the neuropsychiatric safety concerns.

FDA Approval Milestones: Singulair received FDA approval for asthma (1998), allergic rhinitis (2001), and exercise-induced bronchoconstriction (2007), demonstrating its therapeutic versatility across respiratory conditions.

Clinical Impact: Before the 2020 boxed warning, Singulair was one of the most prescribed asthma medications globally, with peak annual sales of approximately $4.5 billion. The drug represented an important advancement as an oral leukotriene receptor antagonist, offering an alternative to inhaled corticosteroids.

Generic Availability: The 2012 patent expiration and subsequent generic montelukast availability expanded patient access to the medication at lower costs.

FDA Boxed Warning (2020): The FDA announced a boxed warning for Singulair and generic montelukast, alerting the public to the risk of neuropsychiatric events including depression, suicidal thoughts, and behavioral changes. The warning was based on mounting evidence of mental health complications associated with the medication. The FDA recommended that healthcare providers consider the risks before prescribing montelukast for patients with mild symptoms, particularly allergic rhinitis. (FDA)

FDA Research on Molecular Link (November 2024): U.S. government researchers found new evidence of a molecular link between montelukast and neuropsychiatric problems. The FDA research identified potential mechanisms by which the drug affects the brain, reinforcing the 2020 boxed warning and leading to increased scrutiny. (CNBC)

Singulair Lawsuits (2025-2026): Numerous lawsuits have been filed against Merck by patients who experienced neuropsychiatric injuries allegedly caused by Singulair. The lawsuits allege that Merck was aware of the risk of neuropsychiatric problems but failed to provide adequate warnings to patients and healthcare providers. As of 2026, litigation is ongoing. (Forbes Advisor)

New York Attorney General Letter: The New York Attorney General sent a letter to the FDA urging stronger warnings and restrictions on Singulair, citing concerns about inadequate patient and provider awareness of neuropsychiatric risks. (NY AG)

Patent Expiration Impact (2012): Singulair's patent expired in 2012, leading to widespread generic montelukast availability. While this reduced branded revenue significantly, it also expanded patient access to affordable treatment. The generic versions are subject to the same FDA boxed warning.

Merck to Organon Transfer (2021): The transfer of Singulair from Merck to Organon as part of the 2021 spinoff created questions about liability for the neuropsychiatric side effects. Lawsuits have targeted both Merck (as the original developer) and Organon (as the current marketer), creating complex legal proceedings.