Chremos A N
J Clin Gastroenterol. 1987;9 Suppl 2:7-12. doi: 10.1097/00004836-198707002-00003.
Famotidine is a competitive histamine H2-receptor antagonist. Its main pharmacodynamic effect in humans is inhibition of gastric acid secretion. Dose-related suppression of basal and stimulated (meal, pentagastrin) gastric acid output has been shown with oral doses of 5-40 mg. The 40 mg dose is associated with the highest inhibitory effect, the longest duration of action, and the greatest response uniformity. After oral administration, antisecretory activity begins within 1 h, reaches a maximum in 1-3 h, and lasts 10-12 h. In addition to the earlier onset of effect, intravenous famotidine is about twice as potent as oral, a result consistent with a systemic bioavailability of oral famotidine of about 43%. Studies in patients and in healthy volunteers have shown that famotidine does not affect cardiovascular, renal, endocrine, pancreatic exocrine, or gastrointestinal motility functions. Oral famotidine is incompletely absorbed, reaching peak plasma concentrations in 1-3 h. It is eliminated primarily through the kidneys (about 70%), mostly as the parent compound. Its average elimination half-life in healthy subjects is 2.8 h. Half-life is prolonged nonlinearly in patients with decreased renal function. To date, clinically important interactions with other drugs have not been described for famotidine.
法莫替丁是一种竞争性组胺H2受体拮抗剂。它在人体中的主要药效学作用是抑制胃酸分泌。口服5 - 40毫克剂量已显示出与剂量相关的基础胃酸分泌和刺激胃酸分泌（进食、五肽胃泌素）的抑制作用。40毫克剂量具有最高的抑制效果、最长的作用持续时间和最大的反应一致性。口服给药后，抗分泌活性在1小时内开始，在1 - 3小时达到峰值，并持续10 - 12小时。除了起效更早外，静脉注射法莫替丁的效力约为口服的两倍，这一结果与口服法莫替丁约43%的全身生物利用度一致。对患者和健康志愿者的研究表明，法莫替丁不影响心血管、肾脏、内分泌、胰腺外分泌或胃肠动力功能。口服法莫替丁吸收不完全，在1 - 3小时达到血浆峰值浓度。它主要通过肾脏排泄（约70%），大部分以母体化合物形式排出。在健康受试者中其平均消除半衰期为2.8小时。在肾功能减退的患者中，半衰期呈非线性延长。迄今为止，尚未发现法莫替丁与其他药物有临床重要的相互作用。
