Your attorney is bound by ethics not to reveal whatever you tell them without your permission. However, they cannot legally present evidence in a case that they know to be false or allow you to commit perjury (lying while testifying in court). An attorney who knows their client to be guilty of a drug induced death charge can still argue that the jury should acquit (meaning to free someone from a criminal charge by a verdict of not guilty) by looking for mistakes made by law enforcement and by poking holes in the prosecution's theory in order to raise a reasonable doubt. In fact, protecting your constitutional rights is your criminal defense lawyer's highest obligation, so it would be in your best interest to be truthful with your drug induced death charges attorney so they can advise you of your best course of action.