You may want to learn more about NKH, or other metabolic diseases. The
following links are good start:
MEDLINE.A searchable on-line database. Available at this site is the
well-known medicine database that cover most publications in medicine from
1960s.
Dextromethorphan
Frequently Ask Questions (FAQ). This links to a FAQ compiled by
William E. White. Although it also discusses dextromethorphan's recreational
use, it offers a very comprehensive coverage of dextromethorphan.