Fig. 4. Pain scores after drug treatment in the context of meaningful analgesia. Individual pain scores for each group are plotted for women receiving butorphanol (closed circles ), meperidine ( open circles ), or their combination ( closed squares ). The line represents the Boltzmann fit of data from Beilin et al. 11 indicating the likelihood that women will request additional analgesia as a function of level of pain. A minority of pain scores after drug administration fall in a low enough range where women would not normally request additional analgesia.