Mercy Ships is a Christian organisation that runs hospital ships, that visit developing countries (see http://www.mercyships.org.uk/). It has produced a drug formulary, which lists the drugs which it tries to make available to its ships. The list is based on the recommendations of the WHO Model Essential Medicines List.
The formulary is downloadable, as one file, or in sections, from http://www.ms-information.org/medical/programsframe.htm. There are also Powerpoint presentations about the formulary, available from the same site.