Enantiomerically pure opioid diarylmethylpiperzine and methods of using same

A method of reducing, treating or preventing drug-mediated respiratory depression in an animal, comprising:

• administering to the animal a pharmaceutical composition comprising:
• (1) an effective amount of a therapeutic agent having a respiratory depression side effect, and
• (2) an effective amount of a compound of the formula:
• 8
• (−)3-((S)-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)(3-thienyl)methyl)phenol or a pharmaceutically acceptable ester and or salt thereof, wherein the compound acts to attenuate the respiratory depression side effect of the therapeutic agent without precluding the therapeutic efficacy of the therapeutic agent.

A pharmaceutical composition comprising:

• (a) an effective amount of a bioactive agent for treatment of a condition selected from the group consisting of 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, functional pain, non-ulcerogenic dyspepsia, organ transplant rejection, skin graft rejection, cardiac disorders, mental disorders, emotional disorders, cognitive disorders;
• emesis;
• respiratory depression;
• acne and skin lesions;
• and
• (b) an effective amount of a compound comprising the formula:
• 10
• (−)3-((S)-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)(3-thienyl)methyl)phenol or a pharmaceutically acceptable ester or salt thereof.