DuPont H L, Ericsson C D, Johnson P C, Bitsura J A, DuPont M W, de la Cabada F J
JAMA. 1987 Mar 13;257(10):1347-50.
Within 48 hours of arrival in Mexico, 182 US students participated in a study to compare the efficacy of two dosages of bismuth subsalicylate (262 mg per tablet) as a prophylactic agent against diarrhea. The students were randomly assigned to receive two tablets (high dose) or one tablet (low dose) of bismuth subsalicylate four times daily or a placebo four times daily during a three-week period. Among these completing the trial, diarrhea (four or more unformed stools in 24 hours or three in eight hours, plus one other symptom) occurred in seven (14%) of 51 receiving the high-dose regimen compared with 15 (24%) of 63 receiving the low-dose regimen and 23 (40%) of 58 in the placebo group. Protection rates were 65% for high-dose and 40% for low-dose bismuth subsalicylate. Diarrhea caused by enterotoxigenic Escherichia coli was found in one student receiving the high-dose regimen, in no students receiving the low-dose regimen, and in seven placebo-treated subjects. Bismuth subsalicylate was well tolerated; the most common side effects were blackening of tongues and stools. Bismuth subsalicylate use in both dosages was associated with tinnitus at a low, clinically insignificant frequency of 1.2 days per 100 days of treatment. The dosage of two tablets of bismuth subsalicylate four times daily (2.1 g/d) appears to be a safe and effective means of reducing the occurrence of travelers' diarrhea among persons at risk for periods up to three weeks.
抵达墨西哥后的48小时内，182名美国学生参与了一项研究，以比较两种剂量的碱式水杨酸铋（每片262毫克）作为预防腹泻药物的疗效。在为期三周的时间里，学生们被随机分配，分别每日四次服用两片（高剂量）或一片（低剂量）碱式水杨酸铋，或每日四次服用安慰剂。在完成试验的学生中，接受高剂量方案的51人中有7人（14%）出现腹泻（24小时内有四次或更多不成形大便，或八小时内有三次，外加一种其他症状），接受低剂量方案的63人中有15人（24%）出现腹泻，安慰剂组的58人中有23人（40%）出现腹泻。高剂量碱式水杨酸铋的保护率为65%，低剂量为40%。在接受高剂量方案的一名学生中发现了由产肠毒素大肠杆菌引起的腹泻，接受低剂量方案的学生中无人出现这种腹泻，而在接受安慰剂治疗的受试者中有7人出现。碱式水杨酸铋耐受性良好；最常见的副作用是舌头和大便变黑。两种剂量的碱式水杨酸铋使用时，耳鸣的发生频率较低，每100天治疗时间出现1.2天，在临床上无显著意义。每日四次服用两片碱式水杨酸铋（2.1克/天）的剂量似乎是一种安全有效的方法，可在长达三周的时间内降低有风险人群中旅行者腹泻的发生率。
