New drug development costs between 500 million and 2 billion dollars and takes 10-15 years, with a success rate of less than 10%. Drug repurposing is the process of discovering new indications for existing drugs and is becoming an important component of drug development as success rates for novel drugs in clinical trials decrease and costs increase. In the period 2007-2009, drug repurposing led to the launching of 30-40% of new drugs. Typically, a new indication for an available drug is identified by accident. However, new technologies and a huge amount of available resources enable us to develop systematic approaches to identify and validate drug repurposing candidates with significantly lower cost. A variety of resources have been utilized to identify novel drug repurposing candidates such as biomedical literature, clinical notes, and genetic data. In this study, we plan to 1) assess the usability and usefulness of new resources, specifically social media and phenome-wise association studies in drug repurposing, and 2) improve some previous proposed approaches, by investigating more accurate methods to prioritize and rank the generated drug repurposing candidates by literature-based discovery.