西咪替丁的临床药物动力学。
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索莫吉氏,古格勒R
西咪替丁的临床药物动力学。
Pharmacokinet。1983; 11 - 12月8日(6):463 - 95。doi: 10.2165 / 00003088-198308060-00001。
- PubMed ID
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6418428 (在PubMed]
- 文摘
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西咪替丁是第一组胺H2-receptor拮抗剂与广泛的临床应用。弱碱和高度水溶性化合物,可以以生物液体的高压液相色谱测定方法。通过静脉注射后,血浆浓度剖面遵循multicompartmental特征。总系统间隙高(500到600毫升/分钟)和主要由肾清除率。的体积分布(Vdβ或vds公司)的1 L /公斤,这等于体重。消除半衰期大约是2个小时。西咪替丁口服后2血浆浓度峰值经常观察,可能由于不连续在肠道吸收。在健康受试者的绝对生物利用度约为60%。消化性溃疡疾病患者,生物利用度约为70%,但在健康受试者的差异远远大于。吸收和清除200和800毫克剂量后西咪替丁都是线性的。 Mean steady-state plasma concentrations on a standard 1000mg daily dose are 1.0 microgram/ml (range 0.64-1.64 micrograms/ml) and are reproducible after treatment periods of up to 2 years. When taken with food, the extent of absorption is unaltered, but a delay occurs and only 1 peak in the plasma concentration curve is apparent. Partial gastrectomy (Billroth I, II) causes an increase in systemic availability of cimetidine by an unclear mechanism. Distribution of cimetidine leads to extensive uptake into kidney, lung and muscle tissues. It distributes into the cerebrospinal fluid (CSF) at a ratio of 0.1 to 0.2 compared with plasma. The mean saliva to plasma ratio is 0.2 (range 0.1-0.55). Plasma protein binding is 20%, and there is no relevant effect of changes in binding on the pharmacokinetics of cimetidine. Uptake of cimetidine into red blood cells leads to concentrations equal to those in plasma. Between 50 and 80% of the dose administered intravenously is recovered in urine as unchanged cimetidine. This fraction is less after oral doses, but is independent of the amount of the dose. In ulcer patients, 40% is recovered unchanged in urine after oral administration. Biliary excretion of cimetidine accounts for only 2% of the dose.(ABSTRACT TRUNCATED AT 400 WORDS)
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- 药物
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