Analgesic Properties of 4-Ethoxycarbonyl-1-(2-Hydroxy-3-Phenoxypropyl) 4-Phenylpiperidine (B.D.H.200) and Some Related Compounds

Twenty-one 3-aryloxy or 3-alkoxy-2-hydroxy-n-propyl derivatives of norpethidine were tested subcutaneously for analgesic activity in mice. Many of them are more potent than pethidine. The 2-hydroxy-3-phenoxypropyl derivative (B.D.H. 200) is at least three times more active than morphine and ten times more active than pethidine in this species with a therapeutic index slightly better than morphine and very much better than pethidine. The duration of analgesia is similar to morphine and pethidine and it is less constipating than pethidine. Its effects on respiration and the cardiovascular systems are counteracted by nalorphine. The decrease in activity after oral administration is probably due to a more rapid metabolic breakdown than poor absorption, as this decrease in activity can be modified by pretreatment with iproniazid and BAL while subcutaneous administration is unaffected.