The card does not speak of taking it together with heart medication and other drugs. It recommends consulting a doctor before use and does not recommend the supplement for people with individual intolerance to the components. The claim of a “cardiotonic” effect has no confirmation and is not repeated here.
General information (not a manufacturer's instruction): supplements with hawthorn and magnesium can interact with blood-pressure and heart medication, so the doctor must be told about taking it in advance.