Patient-controlled analgesic administration. A comparison of steady-state morphine infusions with bolus doses. The authors have shown previously that bone marrow transplant (BMT) patients who self-administered bolus doses of morphine gained equal oral mucositis pain relief while using less drug compared with similar patients receiving morphine by staff-controlled continuous infusion. In a follow-up study they compared the efficacy and side effects of morphine in two groups of marrow transplant patients who controlled their own analgesic administration either by conventional bolus-dose, patient-controlled analgesia (PCA) or by adjusting the rate of continuous morphine infusion to increase or decrease their plasma morphine concentration. Patients controlling their morphine infusion rates (pharmacokinetically based patient-controlled analgesia [PKPCA] group) obtained more relief from oral mucositis pain than did patients using conventional PCA. Patients in the PKPCA group used more morphine than PCA patients and achieved superior pain relief without significant increases in side effects (e.g., nausea, mood changes, sedation). The authors conclude that PKPCA improves the management of prolonged, severe pain in marrow transplant patients and that this approach to patient-controlled analgesia may be useful in other types of persistent pain. 