Graves N M, Holmes G B, Kriel R L, Jones-Saete C, Ong B, Ehresman D J
College of Pharmacy, University of Minnesota, Minneapolis 55455.
DICP. 1989 Jul-Aug;23(7-8):565-8. doi: 10.1177/1060028089023007-806.
Rectal administration of antiepileptic drugs may be a useful alternative route when oral administration is not possible due to illness, surgery, or status epilepticus. Although parenteral administration often replaces oral administration in these circumstances, there is not always a desirable intravenous line available or repeated intramuscular injections may not be practical. The purpose of this study was to determine the relative bioavailability and time course of absorption of the commercially available parenteral phenobarbital sodium solution administered rectally in comparison with the same preparation given intramuscularly. Seven healthy adult volunteers were given phenobarbital 5 mg/kg intramuscularly and rectally five weeks apart. Eighteen blood samples were drawn over 288 hours. Pharmacokinetic parameters following intramuscular versus rectal administration were the following: area under the curve 5916 vs. 5253 mumol.h/L; half-life 112 vs. 113 h; time to maximum concentration 2.1 vs. 4.4 h; and maximum serum concentration 36.2 vs. 31.4 mumol/L. Mean relative bioavailability for rectal phenobarbital was 90 percent. Therefore, the parenteral phenobarbital sodium solution given rectally is well absorbed and provides a useful alternative route of administration.
当因疾病、手术或癫痫持续状态而无法进行口服给药时，直肠给药抗癫痫药物可能是一种有用的替代途径。尽管在这些情况下胃肠外给药常常取代口服给药，但并非总能获得理想的静脉通路，或者重复肌内注射可能并不实际可行。本研究的目的是确定与肌内注射相同制剂相比，直肠给予市售胃肠外苯巴比妥钠溶液的相对生物利用度和吸收时程。七名健康成年志愿者分别于相隔五周的时间接受了5mg/kg苯巴比妥的肌内注射和直肠给药。在288小时内采集了18份血样。肌内注射与直肠给药后的药代动力学参数如下：曲线下面积5916对比5253μmol·h/L；半衰期112对比113小时；达峰时间2.1对比4.4小时；以及最大血清浓度36.2对比31.4μmol/L。直肠给予苯巴比妥的平均相对生物利用度为90%。因此，直肠给予胃肠外苯巴比妥钠溶液吸收良好，提供了一种有用的替代给药途径。
