The article presents research in secondary use of information about medical entities that are automatically extracted from the free text of hospital patient records. To capture patient diagnoses, drugs, lab data and status, four extractors that analyse Bulgarian medical texts have been developed. An integrated repository, which comprises the extracted entities and relevant records of the hospital information system, has been constructed. The repository is further applied in experiments for discovery of adverse drug events. This paper presents the extractors and the strategy of assigning time anchors to the entities that are identified in the patient record texts. Evaluation results are summarised as well as application scenarios which make use of the extracting tools and the acquired integrated repository.