Under a theory of product liability, Merck had a duty to warn consumers of known dangers or harmful side-effects that may result after taking a drug. In this case, Merck lists on its website to only take one Propecia pill (1 milligram) a day, not to take multiple pills if a dose is missed, and that increasing the amount of Propecia taken daily has no known benefit.  Recent study results have shown a link between taking 5 milligrams daily of Finasteride – the active drug in Propecia – and an increased risk prostate cancer.  However, an experienced attorney can explain your legal rights.