Merck Grapples With Lawsuits Over Underplayed Neurological Risks Linked to Singulair

Merck, a global healthcare company, is being besieged by lawsuits alleging the underrepresentation of potential neurological side effects of its asthma and allergy drug, Singulair. Early studies hinted at possible brain impacts, which the company is accused of downplaying.

Originally marketed with assurances that its distribution into the brain was minimal and with no warning of psychiatric side effects, Merck's safety claims have since come under harsh criticism as investigations revealed many patients who had died by suicide or experienced neuropsychiatric issues after taking Singulair.

This crisis has spotlighted the research of cell biologist Julia Marschallinger and her team at Austria's Institute of Molecular Regenerative Medicine, whose work showed that Singulair's impact on the brain was more extensive than described on the label. In fact, the FDA cited Marschallinger's research when it mandated a "black-box" warning for the drug in 2020.

One troubling fact is Merck's original Singulair patent, which referenced other intended uses for the drug, including treating "cerebral spasm," a neurological condition. Lawsuits against Merck cite this patent as evidence of the company's knowledge of the drug's neurological risks.

Critics have also pointed to FDA analyst reports from the 1990s, which claim that only a trace amount of Singulair could be detected in the brain. However, this information relied solely on company assurances, and Marschallinger's findings, based on Merck's original research, paint a very different picture.

Marschallinger and her team identified Singualair's potential neuro-impact as early as 2011 and were hoping to explore its possible use in treating dementia. The drug's documented psychiatric side effects caught their attention, leading them to investigate whether the medication could benefit older patients with cognitive decline.

Merck faces an enormous challenge in rebuilding public trust and restoring confidence in its product as this legal battle unfolds.

In 2014, a group of Austrian scientists took a closer look at Merck's original animal studies on Montelukast, a drug used primarily to manage asthma. What did they find? Well, everywhere in the body saw decreasing amounts of the drug 24 hours post-dosage, except for the brain - which saw an increase! In fact, the amount of Montelukast in the brain surpassed that of the blood and lungs.

The researchers found that a "substantial amount" of the drug had entered the brain, contradicting Merck's "minimal" distribution claim. The FDA later acknowledged Merck's animal studies were "quite limited" and could not provide a complete understanding of the drug's effects on the brain.

While the FDA admitted that Montelukast likely enters the brain, they did not see specific harm in the 2015 study by the Austrian scientists. Some researchers, like Marschallinger, argue that the drug's impact on brain function should have been further analyzed once reports of mental health issues started emerging.

Photo: Towfiqu barbhuiya/Unsplash