Nightingale C H
Department of Research, Hartford Hospital, Connecticut 06115-0729.
Pharmacotherapy. 1993 Mar-Apr;13(2 Pt 2):34S-38S.
It is advisable to switch patients from parenteral to oral therapy as soon as practical. High volumes of distribution, coupled with relatively low protein binding, indicate that the quinolones are widely distributed outside extracellular fluid. Interactions with aluminum- or magnesium-containing antacids may be avoided by administering the antacids at least 2 hours after quinolone dosing. Some quinolones with high bioavailability (e.g., ofloxacin) are absorbed as reliably and completely after oral administration as when given parenterally, and dosage adjustments for these agents are unnecessary after sequential therapy. Treatment strategies may differ according to the route of drug elimination, and dosage adjustments are required in patients with renal failure who receive quinolones excreted primarily by the kidneys. Theophylline interactions may be more problematic in patients given quinolones that are primarily metabolized by the liver. Quinolones, which have concentration-dependent killing and a long postantibiotic effect, should be administered in the highest tolerated dosage. A method to assess the relative antibacterial efficacy of the quinolones uses the ratio of the Cmax:MIC90 of the organism, compared with a ratio derived from the NCCLS breakpoints for susceptibility.
只要切实可行，建议尽快将患者从肠外给药转换为口服治疗。分布容积大，再加上蛋白结合率相对较低，表明喹诺酮类药物在细胞外液之外广泛分布。通过在喹诺酮给药后至少2小时服用抗酸剂，可避免与含铝或镁的抗酸剂相互作用。一些生物利用度高的喹诺酮类药物（如氧氟沙星）口服给药后的吸收与肠外给药时一样可靠和完全，序贯治疗后无需调整这些药物的剂量。治疗策略可能因药物消除途径而异，对于接受主要经肾脏排泄的喹诺酮类药物的肾衰竭患者，需要调整剂量。在使用主要经肝脏代谢的喹诺酮类药物的患者中，与茶碱的相互作用可能更成问题。喹诺酮类药物具有浓度依赖性杀菌作用和较长的抗生素后效应，应以最高耐受剂量给药。一种评估喹诺酮类药物相对抗菌疗效的方法是使用该微生物的Cmax:MIC90比值，并与根据NCCLS敏感性断点得出的比值进行比较。
