The Basel-based pharmaceuticals group, Novartis, has rejected criticism of one of its drugs, Ritalin, used in the treatment of children suffering from problems of concentration.
Legal action has reportedly been taken against Novartis in the American state of Texas for lack of information concerning side effects of the drug.
The Wall Street Journal reported that a Dallas law firm had filed a lawsuit alleging that Novartis fraudulently promoted Ritalin as a treatment for attention-deficit-hyperactivity disorder.
The suit seeks class-action status on behalf of people who bought the drug and wants unspecified compensatory damages to reimburse the cost of purchases, as well as unspecified punitive damages against Novartis.
Company spokesman Mark Hill in Basel said that allegations in the lawsuit were "without merit" and that Novartis would fight the suit "vigorously".
"Ritalin has been used safely and effectively in the treatment of millions of patients for over 40 years. It is the most prescribed drug for the disorder, with over 170 scientific studies completed in more than 6,000 school-aged children," he added.
Sales of Ritalin total some SFr230 million annually.
swissinfo with agencies