Epigenetic changes such as DNA methylation and histone methylation and 
acetylation alter gene expression at the level of transcription by upregulating, 
downregulating, or silencing genes completely. Dysregulation of epigenetic 
events can be pathological, leading to cardiovascular disease, neurological 
disorders, metabolic disorders, and cancer development. Therefore, identifying 
drugs that inhibit these epigenetic changes are of great clinical interest. In 
this review, we summarize the epigenetic events associated with different 
disorders and diseases including cardiovascular, neurological, and metabolic 
disorders, and cancer. Knowledge of the specific epigenetic changes associated 
with these types of diseases facilitates the development of specific inhibitors, 
which can be used as epigenetic drugs. In this review, we discuss the major 
classes of epigenetic drugs currently in use, such as DNA methylation inhibiting 
drugs, bromodomain inhibitors, histone acetyl transferase inhibitors, histone 
deacetylase inhibitors, protein methyltransferase inhibitors, and histone 
methylation inhibitors and their role in reversing epigenetic changes and 
treating disease.