On Tuesday the Food and Drug Administration warned that a common drug used to treat attention deficit disorder can cause painful and long-lasting erections. The FDA posted a notice on its website warning of priapism affecting males age 8 to 33 years who take drugs containing methylphenidate. The ingredient is found in Novartis AG’s Ritalin and Johnson & Johnson’s Concerta. The FDA also warned of a non-stimulant drug called Strattera that causes similar problems.