Objective To characterise information requests (IRs) from hospitals received by a drug information center (DIC-RS) according to the resolution of the inquiries.

Method The sample consisted of all requestors and their respective IRs registered in the DIC-RS database from January 2012 to December 2016. Request without information in the consulted literature (RWI) were categorised according to the institution of origin. IRs from hospitals were classified by the information source, topic and subtopic of the questions, and the number of drugs and the pharmacological or therapeutic group.

Results A total of 2,500 IRs were analysed. Of those, 25% did not exhibit conclusive information in the consulted sources. RWI from hospitals represented 51% of all RWI, followed by those from community pharmacies (13%) and health centres (9%). Tertiary literature was the most commonly used source (73%) for IRs from hospitals. The greatest difficulties in finding information were related to off-label drug administration and indication issues (52% of RWI). The most common type of off-label use was related to changes in the original pharmaceutical form of the drug. Furthermore, 61% of RWI were directed at a specific drug, mostly systemic anti-infectives.

Conclusion We found that a quarter of the answers did not exhibit conclusive information in the consulted sources. Answers to IRs from the hospital environment exhibited the greatest extent of limited information, and off-label use was responsible for most cases.