The Harry R Horvitz Center for Palliative Medicine, Cleveland, OH 44195, USA.
Palliat Med. 2010 Jan;24(1):9-16. doi: 10.1177/0269216309346595. Epub 2009 Nov 12.
Morphine (M) is the opioid analgesic of choice for severe cancer pain. The IV to PO M equipotent switch ratio (CR) is controversial. We designed this prospective observational cohort to confirm the efficacy and safety of M IV to PO CR of 1:3. Consecutive cancer patients admitted to an inpatient palliative medicine unit were screened for inclusion. Pain was managed by palliative medicine specialists. They were blinded to the patient data collected, and the calculated CR. The switch was considered successful if the following criteria were met: (1) Pain adequately controlled: pain rated as none or mild (2) Number of RD less than 4 (for non incident pain) per 24 hours (3) No limiting side effects. We used Day 3 ATC M dose for CR calculations. The major outcome measures were the IV : PO CR ratio, morphine doses (mg/day), pain severity, number of PRN doses, and day 1 and day 3side effects. Descriptive statistics were used to report mean, median, standard deviation and range of different variables. Two hundred and fifty six consecutive admissions were screened, and 106 were eligible for the study. Sixty two underwent a successful M route switch and were included in this analysis. A ratio of 1:3 was safely implemented over a wide M dose range. About 80% were successfully switched with a calculated CR of 1:3. 20% required an oral M dose adjustment after route switch either to better pain control or reduce side effects with a resultant higher (e.g. 1:4) or lower (e.g. 1:2) calculated potency ratios respectively. A potency ratio of 1:3 was safe as evaluated by common M side-effects, the dose also easy to calculate. The 1: 3 M IV to PO relative milligram potency ratio appears correct and practical for most patients over a wide M dose range.
吗啡（M）是治疗严重癌痛的首选阿片类镇痛药。静脉到口服吗啡等效剂量转换比（CR）存在争议。我们设计了这项前瞻性观察性队列研究，以证实静脉到口服吗啡 CR 为 1:3 的疗效和安全性。连续入组收入姑息医学住院病房的癌症患者进行入选筛查。姑息医学专家负责疼痛管理。他们对收集的患者数据和计算的 CR 不知情。如果符合以下标准，则认为转换成功：（1）疼痛得到充分控制：疼痛评为无或轻度；（2）24 小时内非突发性疼痛的 RD 数少于 4 次；（3）无限制副作用。我们使用第 3 天 ATC M 剂量进行 CR 计算。主要结局指标是 IV:PO CR 比值、吗啡剂量（mg/天）、疼痛严重程度、PRN 剂量数以及第 1 天和第 3 天的副作用。使用描述性统计报告不同变量的均值、中位数、标准差和范围。对 256 例连续入院患者进行了筛查，其中 106 例符合研究条件。62 例患者成功进行了 M 途径转换，纳入本分析。在广泛的 M 剂量范围内安全实施了 1:3 的比例。约 80%的患者成功转换，计算的 CR 为 1:3。20%的患者在途径转换后需要调整口服 M 剂量，以更好地控制疼痛或减少副作用，导致计算的效力比分别更高（例如 1:4）或更低（例如 1:2）。根据常见的 M 副作用评估，1:3 的效力比是安全的，剂量也易于计算。对于大多数患者，在广泛的 M 剂量范围内，1:3 的 M 静脉到口服相对毫克效力比似乎是正确和实用的。
