Intravenous patient-controlled therapy is used routinely in postoperative care in much of the developed world. Intravenous patient-controlled analgesia results in higher patient satisfaction than conventional administration of analgesics, although it appears to have no advantage over conventional analgesia in terms of adverse effects and consumption of opioids. Standard orders and nursing procedure protocols are recommended for patients receiving intravenous patient-controlled analgesia to monitor treatment efficacy and development of adverse effects. Some subgroups of patients need special consideration. For example, opioid-tolerant patients need higher postoperative opioid doses to achieve satisfactory analgesic effect. In patients with renal or hepatic insufficiency, the elimination of some opioids may be substantially impaired, and the optimal opioid should be selected based on its pharmacokinetic properties.