Vanakoski J, Seppälä T
Department of Pharmacology and Toxicology, University of Helsinki, Finland.
Int J Clin Pharmacol Ther. 1997 May;35(5):204-7.
Renal blood flow is known to be reduced during intensive external heating, which may have clinical relevance for renal drug elimination as well. The effects of heat exposure in a sauna bath on tetracycline pharmacokinetics were studied in 8 healthy volunteers in an open, randomized crossover study. The subjects were given a single oral dose of tetracycline (500 mg) both in a control session and in a sauna bathing session. The heat exposure consisted of three 10-minute stays in a sauna bath (temperature 76-87 degrees C, relative humidity 27-33%) starting 20 minutes after drug administration. The stays in the steam room were separated by two 5-minute cooling periods at 23 degrees C. Venous blood samples for determination of plasma tetracycline concentrations were taken 15 min before the drug intake, 20, 40, 60 min, and 2, 3, 4, 6, 8, and 24 h after it. The control session at room temperature (23 degrees C) followed the same sampling protocol. No statistically significant differences in tetracycline plasma concentrations, Cmax, Tmax, or AUC0-24h were seen. In addition, urine was collected (0-2 h, 2-5 h, 5-8 h, and 8-24 h) for determination of the amount of tetracycline excreted unchanged. Urinary tetracycline excretion was transiently (2-5 h after drug intake) reduced in the sauna session (P < 0.05 vs. control, Wilcoxon). The other collection periods and the total urinary excretion of tetracycline (24 h) did not differ from the control session. It is concluded that urinary tetracycline excretion was transiently decreased during short-term heat exposure, but otherwise the effects of external heating on tetracycline pharmacokinetics were negligible.
已知在外部强烈加热期间肾血流量会减少，这可能对肾脏药物清除也具有临床意义。在一项开放、随机交叉研究中，对8名健康志愿者研究了在桑拿浴中受热对四环素药代动力学的影响。在对照期和桑拿浴期，受试者均单次口服一剂四环素（500毫克）。受热过程包括在给药后20分钟开始在桑拿浴中停留三次，每次10分钟（温度76 - 87摄氏度，相对湿度27 - 33%）。在蒸汽室的停留之间有两个在23摄氏度的5分钟冷却期。在服药前15分钟、服药后20、40、60分钟以及2、3、4、6、8和24小时采集静脉血样本以测定血浆四环素浓度。室温（23摄氏度）下的对照期遵循相同的采样方案。未观察到四环素血浆浓度、Cmax、Tmax或AUC0 - 24h有统计学显著差异。此外，收集尿液（0 - 2小时、2 - 5小时、5 - 8小时和8 - 24小时）以测定未改变排泄的四环素量。在桑拿浴期，四环素尿排泄在服药后2 - 5小时短暂减少（与对照相比，Wilcoxon检验，P < 0.05）。其他收集期以及四环素的总尿排泄量（24小时）与对照期无差异。得出的结论是，在短期受热期间，四环素尿排泄短暂减少，但除此之外，外部加热对四环素药代动力学的影响可忽略不计。
