Coordinating subheadings on two or more headings:
/drug therapy on a disease term usually requires /therapeutic use on one or more drug terms.
"Treatment of HIV infections with HIV protease inhibitors" is indexed as:
HIV Infections/drug therapy
HIV Protease Inhibitors/therapeutic use
/metabolism on an endogenous compound may require /metabolism on an organ, an organism, and/or a disease term.
"Inability to metabolize copper" (as in Wilson's Disease) is indexed as:
/pathology on a disease term often requires /pathology on an organ term.