Merck Exits Singulair Psychiatric Side-Effect Warning Lawsuit

Merck & Co. defeated a lawsuit alleging its asthma drug Singulair caused a child’s suicidal and homicidal thoughts, after a federal court in Wisconsin said federal drug labeling law preempts the 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 the plaintiffs’ lawsuit barred by conflict preemption principles because Merck couldn’t have complied with federal obligations and those the plaintiffs said were required by state law, the court said Wednesday.

The child, identified as R.S.B., was prescribed Singulair from December 2010 until August 2012. He ...