Gene and Drug Landing Page Aggregator
Gene and Drug Landing Page Aggregator (GDLPA) has links to 53 gene, 18 variant and 19 drug repositories that provide direct links to gene and drug landing pages. You can search by gene or drug name and then choose the sites that contain knowledge about your gene or drug of interest. Resources supported by the NIH Common Fund are listed first and have the CFDE logo at their top right corner.
Drug-drug interactions (DDIs) from literature :

Therapeutic Target Database (TTD) is a database to provide information about the known and explored therapeutic protein and nucleic acid targets, the targeted disease, pathway information and the corresponding drugs directed at each of these targets.

ChEMBL is a manually curated database of bioactive molecules with drug-like properties. It brings together chemical, bioactivity and genomic data to aid the translation of genomic information into effective new drugs.

STITCH is a database of known and predicted interactions between chemicals and proteins and a functional enrichment tool.

DrugCentral provides information on active ingredients chemical entities, pharmaceutical products, drug mode of action, indications, pharmacologic action.

DrugEnrichr is a new drug set enrichment analysis tool.

The Open Targets Platform is a comprehensive tool that supports systematic identification and prioritisation of potential therapeutic drug targets by integrating publicly available datasets including data generated by the

PubChem, an open chemistry database at the NIH, mostly contains small molecules, but also larger molecules such as nucleotides, carbohydrates, lipids, peptides, and chemically-modified macromolecules.

Drugmonizome is a web portal for querying sets of known drugs and computing significant biomedical terms that drugs in the set share.

PubMed comprises more than 33 million citations for biomedical literature from MEDLINE, life science journals, and online books.

The Guide to Pharmacology is a searchable database of drug targets and the prescription medicines and experimental drugs that act on them.

SigCom LINCS data portal serves LINCS datasets and signatures. It provides a signature similarity search to query for mimicker or reverser signatures.

Wikipedia is a free content, multilingual online encyclopedia written and maintained by a community of volunteers through a model of open collaboration, using a wiki-based editing system