Researchers identified five unapproved drugs in dangerous combinations and doses in over-the-counter cognitive enhancement drugs. Side effects of the unapproved drugs include increases and decreases in blood pressure, agitation, and sedation.approved drugs in dangerous combinations and doses in over-the-counter cognitive enhancement drugs. Side effects of the unapproved drugs include increases and decreases in blood pressure, agitation, and sedation.approved drugs in dangerous combinations and doses in over-the-counter cognitive enhancement drugs. Side effects of the unapproved drugs include increases and decreases in blood pressure, agitation, and sedation.