I guess the most appropriate translation for "formulary" is "formula", which is a term widely used in pharmacy, but these kind of drugs are just known as "medicamentos genéricos", at least in Spain. Maybe other coleagues from Southamerica may have different terms.

As for the glossaries, medicine is not my main field of experitise, but I don't know any good on-line bilingual resource. The good thing with medicine is that most of terms are very similar in English and Spanish, so a good advice a teacher at uni gave me was asking my doctor to give me one of his old guidebooks, what we cal in Spanish, "vademecum". It is very useful.

my english medical dictionary has for formulary: "a book containing a list of medicinal substances and formulas."

i'm not sure if formulario works, but that's an option. either that or libro or listado, or something else along those lines.

here's few medical and chem sites i've found helpful:

http://eurodic.ip.lu/
http://accurapid.com/journal/16org.htm
http://www.geocities.com/devalve2000/sub-medisch.html
http://www.medsite.com/
http://www.medscape.com/
http://medisurf.ese-metz.fr/index2.htm
http://www.diahome.org/tttt/english/TTEnglish.htm
www.mercator-hs.be/medisch/en/glos15.html
http://www.accurapid.com/journal/13org.htm
http://ccinfoweb.ccohs.ca/chemindex/Action.lasso
http://ccinfoweb.ccohs.ca/cheminfo/Action.lasso
http://www.msds.org/

sorry, i'm taking back my last answer. i didn't really look at he context close enough.
i still hope you enjoy the links.

http://allserv.rug.ac.be/~rvdstich/eugloss/welcome.html

Multilingual Glossary of technical and popular medical terms in nine European Languages
This project was commissioned by The EuropeanCommission(DG III) and executed by Heymans Institute of Pharmacology and Mercator School, Department of applied Linguistics.

I don\'t know how complete it is, but it\'s probably worth a look.

Good luck

Pamela
Estas segura que no se te olvido alguna palabra?
Formulary es formulario, pero meparece que es necesario leer un pocomas de tu contexto. Tengo la impresion que se te quedo fuera algoa si como "list" "prescriptions".
Si no es asi, sugeriria:
drogas genericas del formulario ... (medico?). Las drogas genericas e.g penicilina, son comericializadas y vendidas por companias farmaceuticas con otros nombres: aspirina: Alka Seltzer, Mejoral, etc.

Efectivamente, "formulary" como han dicho otros es un libro que contiene un listado de productos farmacéuticos y sus fórmulas, pero "formulary drug" significa, según el Encarta World English Dictionary: "drug covered by benefits: a prescription drug that appears on a list of those covered by healthcare benefits", es decir, lo que en España llamaríamos medicamento (o fármaco) cubierto por la Seguridad Social.