Synergistic Effect of Ibuprofen and Hydromorphone for Postoperative Pain

Drug was administered by the Dixon and Mood up-and-down method. Starting doses was ibuprofen 50 mg. The maximum doses was ibuprofen 800 mg. Combination index (CI) (additive: 0.9-1.1, synergism: \<0.9, antagonism: \>1.1), dose reduction index (DRI, a measure of how much the dose of each drug in a combination can be reduced), and isobologram were used to define the nature of their interaction.

Drug was administered by the Dixon and Mood up-and-down method. Starting doses was hydromorphone 0.25 mg. The maximum doses was hydromorphone 2 mg. Combination index (CI) (additive: 0.9-1.1, synergism: \<0.9, antagonism: \>1.1), dose reduction index (DRI, a measure of how much the dose of each drug in a combination can be reduced), and isobologram were used to define the nature of their interaction.