Merck Exits Singulair Psychiatric Side-Effect Warning Lawsuit

Merck & Co. defeated a mother’s suit alleging its asthma drug Singulair caused her son’s suicidal and homicidal thoughts, after a federal court in Wisconsin said federal drug labeling law preempts her warning claims.

The drugmaker couldn’t have unilaterally changed the drug’s label, the US District Court for the Eastern District of Wisconsin said. That makes Stephanie Hammar’s lawsuit barred by conflict preemption principlies because Merck couldn’t have complied with federal obligations and those she said were required by state law, the court said Wednesday.

Hammar’s son R.S.B. was prescribed Singulair from December 2010 until August 2012. He was admitted ...