Patel I H, Kaplan S A
Am J Med. 1984 Oct 19;77(4C):17-25.
In human subjects, ceftriaxone exhibits an exceptionally long elimination half-life (5.8 to 8.7 hours) and a small degree of nonlinearity in its pharmacokinetics which can be ignored in its clinical applications. Thirty-three to 67 percent of a dose is excreted in the urine as unchanged drug, and the remainder is secreted in the bile and ultimately is found in the feces as microbiologically inactive compounds. Ceftriaxone is rapidly and completely absorbed following intramuscular administration. Multiple dosing of ceftriaxone with doses ranging from 0.5 to 2 g at 12- or 24-hour intervals by intravenous and intramuscular routes resulted in 15 to 36 percent accumulation of ceftriaxone in plasma and no change in its elimination half-life. The volume of distribution and the plasma clearance of ceftriaxone in pediatric patients were threefold greater than those in adults, and ceftriaxone penetrated the inflamed meninges of infants and children with bacterial meningitis. Small changes in the pharmacokinetics of ceftriaxone in elderly subjects or patients with renal or hepatic dysfunction are such that dose adjustments should not be necessary with a ceftriaxone dosage up to 2 g per day. Ceftriaxone was not removed to any significant extent from plasma by hemodialysis. In a small percentage of patients, on dialysis, the elimination rate of ceftriaxone was significantly reduced, suggesting that plasma concentrations of ceftriaxone should be monitored in these patients to determine if dosage adjustments are necessary.
在人体受试者中，头孢曲松的消除半衰期极长（5.8至8.7小时），其药代动力学的非线性程度较小，在临床应用中可忽略不计。给药剂量的33%至67%以原形药物经尿液排泄，其余部分经胆汁分泌，最终以微生物学上无活性的化合物形式存在于粪便中。肌内注射后，头孢曲松迅速且完全吸收。通过静脉和肌内途径，以0.5至2 g的剂量、12或24小时间隔多次给药头孢曲松，导致血浆中头孢曲松蓄积15%至36%，但其消除半衰期无变化。儿科患者中头孢曲松的分布容积和血浆清除率比成人高两倍，且头孢曲松可穿透患有细菌性脑膜炎的婴幼儿的炎症脑膜。老年受试者或肾功能或肝功能不全患者中头孢曲松的药代动力学变化较小，以至于每天2 g以下的头孢曲松剂量无需调整。血液透析未从血浆中显著清除头孢曲松。在一小部分透析患者中，头孢曲松的消除速率显著降低，这表明应对这些患者的血浆头孢曲松浓度进行监测，以确定是否需要调整剂量。
