Which drug is usually the best choice for patient-controlled analgesia (PCA) for a child in the immediate postoperative period?

• A. Morphine
• B. Hydromorphone
• C. Fentanyl
• D. Methadone

Answer: (A)

PCA in the immediate postoperative period works best with a drug that provides reliable, titratable pain relief over a duration that fits the typical post-op pain trajectory. Morphine fits this need well: it has a well-established, predictable dose-response in children and its analgesia can be effectively tailored through the PCA lockout with a duration that usually covers several hours between boluses. This makes it easy to manage pain while monitoring for respiratory depression and other side effects.

Fentanyl, though potent and fast-acting, has a shorter duration and often requires more frequent dosing or continuous infusion, which can lead to more fluctuations in pain control. Hydromorphone is a valid alternative but in many pediatric protocols morphine is preferred due to longer clinical use and familiarity. Methadone has a long and variable half-life, increasing the risk of delayed respiratory depression and accumulation, making it less suitable for short-term postoperative analgesia.