抗菌药物在老年人的药代动力学

Pharmacokinetics of antimicrobial agents in the elderly

目的 :探讨抗菌药物在老年人的体内过程特点 ,为制订治疗老年人感染的合理给药方案提供依据。方法 :对照研究青霉素、哌拉西林、头孢唑啉、头孢他啶、庆大霉素、阿米卡星、红霉素、氧氟沙星和环丙沙星在老年和年轻志愿者的药代动力学。结果 :与年轻组相比 ,青霉素、哌拉西林、头孢唑啉、头孢他啶、庆大霉素、阿米卡星和氧氟沙星等主要经肾排泄的抗菌药物在老年组的平均T1 /2Kel延长 ,CLr 降低 ,AUC增高 (P <0 .0 5或 <0 .0 1 )。老年组口服氧氟沙星 30 0mgq 1 2h连续 7d后的cmax和AUC较单剂者明显增高 (P <0 .0 5)。老年组和年轻组单剂口服环丙沙星 50 0mg后的药动学参数间差异无显著性。 结论 :青霉素、哌拉西林、头孢唑啉、头孢他啶、庆大霉素、阿米卡星和氧氟沙星等主要经肾排泄的抗菌药物在治疗老年人感染时的每日给药量应减少 ;高龄患者或同时有肝功能减退者以口服红霉素治疗时亦应适当减量 ;环丙沙星则一般仍可按正常剂量给药。

Purpose:To investigate the behavior of pharmacokinetics of commonly used antimicrobial agents in the elderly and provide data for the rational use of drugs in the elderly. Methods:The pharmacokinetics of penicillin G, piperacillin, cefazolin, ceftazidime, gentamicin, amikacin, erythromycin, ofloxacin and ciprofloxacin were studied in the elderly and compared with those in the younger in the same period of time. Results:Compared with the younger, the mean T 1/2β of penicillin G, piperacillin, cefazolin, ceftazidime, gentamicin, amikacin and ofloxacin, which are mainly excreted by kidney, were longer; CL r were lower and AUC were higher in the elderly group than that in the younger group. The differences of the above pharmacokinetic parameters between the two groups were statistically significant. After multiple oral dose of ofloxacin (300mg, q 12 h for 7 days) in the elderly, c max and AUC were markedly increased than those after a single dose ( P < 0.05 ). No significant difference of pharmacokenetic parameters in the elderly in comparison with those in younger qroup were obsesved. Conclusions:The dosage of the antimicrobial agents mainly excreted by kidney in the treatment of infections in the elderly should be adjusted; the dosage of oral erythromycin also should be adjusted in the elderly or in patients with impaired liver function; the normal dosage of ciprofloxacin could be still given in the elderly.