Abstract Purpose There is little research-based documentation on the services provided by drug information centres (DICs). The aim of this multi-centre study was to explore for the first time the factors associated with time consumption when answering drug-related queries at eight different but comparable DICs. Methods During an 8-week period, staff members at eight Scandinavian DICs recorded the number of minutes during which they responded to queries. Mixed model linear regression analyses were used to explore the factors associated with time consumption when answering queries. Results The mean time consumption per query was 178 min (range 4–2540 min). The mean time consumed per query increased by 28 (95 % confidence interval (CI) 23 to 33, p < 0.001) min higher for queries for which there was a lack of documentation and 139 (95 % CI 74 to 203, p < 0.001) min higher when conflicting information was present in the literature. Staff members with less than 1 year of experience consumed a mean of 91 more minutes (95 % CI 32 to 150, p = 0.003) per query than staff members with more than 2 years of experience. Conclusions This study demonstrates the large variation in time consumed answering queries posed to Scandinavian DICs. The results highlight the need for highly competent staff members and easy access to drug information sources. Further studies are required to explore the association between time consumption and response quality.