Montgomery C J, McCormack J P, Reichert C C, Marsland C P
Department of Anaesthesia, University of British Columbia, Vancouver, Canada.
Can J Anaesth. 1995 Nov;42(11):982-6. doi: 10.1007/BF03011069.
Although the recommended dose of rectal acetaminophen (25-30 mg.kg-1) is twice that for oral administration (10-15 mg.kg-1), the literature justifies the use of a higher dose when acetaminophen is administered via the rectal route. We measured venous plasma acetaminophen concentrations resulting from 45 mg.kg-1 of rectal acetaminophen in ten ASA 1, 15 kg paediatric patients undergoing minor surgery with a standardized anaesthetic. After induction of anaesthesia, a single 650 mg suppository (Abenol, SmithKline Beecham Pharma Inc.) was administered rectally. Plasma was sampled at t = 0, 15, 30, 45, 60, 90, 120, 180, 240 min in the first five patients and at t = 0, 30, 60, 90, 120, 180, 240, 300, 420 min in the subsequent five. Acetaminophen plasma concentrations were determined using a TDxFLx fluorescence polarization immunoassay (Abbott Laboratories, Toronto, Ontario). The maximum plasma concentration was 88 +/- 39 mumol.L-1 (13 +/- 6 micrograms.ml-1) and the time of peak plasma concentration was 198 +/- 70 min (mean +/- SD). At 420 min, the mean plasma concentration was 46 +/- 18 mumol.L-1 (7.0 +/- 0.9 micrograms.ml-1). No plasma concentrations associated with toxicity (> 800 mumol.L-1) were identified. A 45 mg.kg-1 rectal dose of acetaminophen resulted in peak plasma concentrations comparable with those resulting from 10-15 mg.kg-1 of oral acetaminophen at three hours after suppository insertion. It is concluded that the delayed and erratic absorption of acetaminophen after rectal administration leads to unpredictable plasma concentrations. Rectal acetaminophen will not be consistently effective for providing rapid onset of analgesia in children.
尽管直肠用对乙酰氨基酚的推荐剂量（25 - 30毫克·千克⁻¹）是口服给药剂量（10 - 15毫克·千克⁻¹）的两倍，但文献表明当通过直肠途径给药时使用更高剂量是合理的。我们测量了10名接受标准化麻醉的ASA 1级、体重15千克的小儿患者，给予45毫克·千克⁻¹直肠用对乙酰氨基酚后静脉血浆中对乙酰氨基酚的浓度。麻醉诱导后，经直肠给予单个650毫克栓剂（阿贝诺，史克必成制药公司）。在前5名患者中，于t = 0、15、30、45、60、90、120、180、240分钟采集血浆样本，在随后的5名患者中于t = 0、30、60、90、120、180、240、300、420分钟采集血浆样本。使用TDxFLx荧光偏振免疫分析法（雅培实验室，安大略省多伦多）测定对乙酰氨基酚血浆浓度。最大血浆浓度为88 ± 39微摩尔·升⁻¹（13 ± 6微克·毫升⁻¹），血浆浓度峰值时间为198 ± 70分钟（平均值 ± 标准差）。在420分钟时，平均血浆浓度为46 ± 18微摩尔·升⁻¹（7.0 ± 0.9微克·毫升⁻¹）。未发现与毒性相关的血浆浓度（> 800微摩尔·升⁻¹）。直肠给予45毫克·千克⁻¹剂量的对乙酰氨基酚后，其血浆浓度峰值与栓剂插入后三小时口服10 - 15毫克·千克⁻¹对乙酰氨基酚所产生的峰值相当。结论是，对乙酰氨基酚经直肠给药后吸收延迟且不稳定，导致血浆浓度不可预测。直肠用对乙酰氨基酚在儿童中不能始终有效地快速起效镇痛。
