I'd like to explore and possibly use (reuse) open XML formats/schemes (DTD/XSD) for drug (medication) prescription documents (Rx) issued by medical doctors and later processed by licenced pharmacists and health insurance companies.
Is there any such freely XSD available and what I have to take care when considering and incorporating into health-care information system?
What international standards (ISO, ISO/IEC, EN) should be used to acheeve maximum level of interoperability?