There are quite a lot drug databases. I think DGIbd is a good place to start (see below). Further there are a lot of databases which describe drugs and their targets, take a look at these (and the links at the bottom) hopefully you can use several of these in your implementation.
SIDER
SIDER contains information on marketed medicines and their recorded
adverse drug reactions. The information is extracted from public
documents and package inserts. The available information include side
effect frequency, drug and side effect classifications as well as
links to further information, for example drug–target relations.
DrugCentral
DrugCentral provides information on active ingredients chemical
entities, pharmaceutical products, drug mode of action, indications,
pharmacologic action. We monitor FDA, EMA, and PMDA for new drug
approval on regular basis to ensure currency of the resource. Limited
information on discontinued and drugs approved outside US is also
available however regulatory approval information can't be verified.
Therapeutic Target Database
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. Also included
in this database are links to relevant databases containing
information about target function, sequence, 3D structure, ligand
binding properties, enzyme nomenclature and drug structure,
therapeutic class, clinical development status. All information
provided are fully referenced.
Potential drug target database (PDTD)
NOTE: I think this one is coupled to DrugBank however you can take a look here
PDTD is a dual function database that associates an informatics
database to a structural database of known and potential drug targets.
PDTD is a comprehensive, web-accessible database of drug targets, and
focuses on those drug targets with known 3D-structures.
PharmGKB
The PharmGKB is a pharmacogenomics knowledge resource that encompasses
clinical information including dosing guidelines and drug labels,
potentially clinically actionable gene-drug associations and
genotype-phenotype relationships. PharmGKB collects, curates and
disseminates knowledge about the impact of human genetic variation on
drug responses through the following activities: Annotate genetic
variants and gene-drug-disease relationships via literature reviews
Summarize important pharmacogenomic genes, associations between
genetic variants and drugs, and drug pathways Curate FDA drug labels
containing pharmacogenomic information Enable consortia examining
important questions in pharmacogenomics Curate and participate in
writing pharmacogenomic-based drug dosing guidelines Contribute to
clinical implementation projects for pharmacogenomics through
collaborations Publish pharmacogenomic-based drug dosing guidelines,
very important pharmacogene summaries and drug-centered pathways
Display all information on the website and provide comprehensive
downloads
STITCH
To facilitate access to this data, STITCH (‘search tool for
interactions of chemicals’) integrates information about interactions
from metabolic pathways, crystal structures, binding experiments and
drug–target relationships. Inferred information from phenotypic
effects, text mining and chemical structure similarity is used to
predict relations between chemicals. STITCH further allows exploring
the network of chemical relations, also in the context of associated
binding proteins. Each proposed interaction can be traced back to the
original data sources. Our database contains interaction information
for over 68 000 different chemicals, including 2200 drugs, and
connects them to 1.5 million genes across 373 genomes and their
interactions contained in the STRING database.
SuperTarget and Metador
An easy-to-use query interface enables the user to pose complex
queries, for example to find drugs that target a certain pathway,
interacting drugs that are metabolized by the same cytochrome P450 or
drugs that target the same protein but are metabolized by different
enzymes. Furthermore, we provide tools for 2D drug screening and
sequence comparison of the targets. The database contains more than
2500 target proteins, which are annotated with about 7300 relations to
1500 drugs; the vast majority of entries have pointers to the
respective literature source. A subset of these drugs has been
annotated with additional binding information and indirect
interactions and is available as a separate resource called Matador.
Pharos
Pharos is the user interface to the Knowledge Management Center (KMC)
for the Illuminating the Druggable Genome (IDG) program funded by the
National Institutes of Health (NIH) Common Fund. (Grant No.
5U54CA189205-02). The goal of KMC is to develop a comprehensive,
integrated knowledge-base for the Druggable Genome (DG) to illuminate
the uncharacterized and/or poorly annotated portion of the DG,
focusing on four of the most commonly drug-targeted protein families:
G-protein-coupled receptors (GPCRs); nuclear receptors (NRs); ion
channels (ICs); and kinases. For more information on opportunities in
the druggable human genome see this poster
KEGG drug
KEGG DRUG is a comprehensive drug information resource for approved
drugs in Japan, USA, and Europe unified based on the chemical
structures and/or the chemical components, and associated with target,
metabolizing enzyme, and other molecular interaction network
information. All the marketed drugs in Japan, not only the
prescription drugs but also the OTC drugs, are fully represented in
KEGG DRUG and integrated with the package insert information (labels
information). These include crude drugs and TCM (Tradictional Chinese
Medicine) drugs.
The IUPHAR/BPS Guide to PHARMACOLOGY (database)
The information in the database is presented at two levels: the
initial view or landing pages for each target family provide
expert-curated overviews of the key properties and selective ligands
and tool compounds available. For selected targets more detailed
introductory chapters for each family are available along with curated
information on the pharmacological, physiological, structural, genetic
and pathophysiogical properties of each target. The database is
enhanced with hyperlinks to additional information in other databases
including Ensembl, UniProt, PubChem, ChEMBL and DrugBank, as well as
curated chemical information and literature citations in PubMed.
DGIbd
The druggable genome can be defined as the genes or gene products that
are known or predicted to interact with drugs, ideally with a
therapeutic benefit to the patient. Such genes are of particular
interest to large-scale cancer profiling efforts such as TCGA, ICGC
and others that identify lists of potential cancer driver genes from
high-throughput sequence and other genome-wide data. In cancer
therapy, the increasing number of targeted drugs--those designed to
inactivate proteins carrying activating amino acid changes as
determined by mutational analyses--make more compelling the need for a
searchable database of drug-gene interactions, available here.
There are a lot more databases, maybe these links will help you:
