Abstract: Diarylmethylbenzylpiperazine compounds, optionally substituted on an aromatic ring of the benzyl substituent with one or more halo substituents, and pharmaceutically acceptable esters and salts of such compounds. Such compounds are usefully employed in therapeutic intervention for treatment or prophylaxis of disease states and conditions such as drug addiction, alcohol addiction, drug overdose, mental illness, cough, lung edema, gastro-intestinal disorders, arthritis, psoriasis, asthma, inflammatory bowel disease, disorders of respiratory function, functional bowel disease, irritable bowel syndrome, diarrhea, functional distension, pain (e.g., functional pain, trauma pain, etc.), non-ulcerogenic dyspepsia, urogenital tract disorders, organ transplant rejection, skin graft rejection, mental disorders, cognitive disorders, emesis, respiratory depression, acne and skin lesions.