氯芬待因片（每片含双氯芬酸２５ｍｇ和磷酸可待因１５ｍｇ）与氨酚待因２号片（每片含扑热息痛３００ｍｇ和磷酸可待因１５ｍｇ）、安慰剂进行双盲对照试验，旨在考察其对手术后疼痛、癌痛、神经痛等中度疼痛患者的临床镇痛效果和不良反应。氯芬待因组３０３例，氨酚待因２号片组３１例，安慰剂组６９例。采用疼痛强度差、总疼痛强度差、疼痛缓解度、中度以上疼痛缓解率等镇痛效果评价指标。结果表明：（１）氯芬待因镇痛效果明显优于安慰剂（Ｐ＜０．００１），某些指标方面亦优于氨酚待因２号片（Ｐ＜０．０５）；（２）氯芬待因不良反应轻微，胃不适、恶心、呕吐在１０％以下，头晕、思睡在５％左右。多在１ｄ内消失。 A double-blind, placebo-controlled placebo was used in the double-blind controlled trial of chlorpheniramine tablets (each containing diclofenac 25 mg and codeine phosphate 15 mg) and paracetamol 2 tablets (each containing acetaminophen 300 mg and phosphate 15 mg) Investigate its clinical analgesic effect and adverse reactions in patients with moderate pain such as postoperative pain, cancer pain, neuralgia. 303 cases in clofenhydrin group, 31 cases in paracetamol and 2 cases in placebo group and 69 cases in placebo group. With pain intensity difference, the total pain intensity difference, pain relief, moderate pain relief rate and other analgesic effect evaluation index. The results showed that: (1) Chlorpheniramine was superior to placebo for the analgesic effect (P <0.001), and some indicators were superior to paracetamol 2 (P <0.05); (2) Chlorpheniramine due to minor adverse reactions, stomach discomfort, nausea, vomiting below 10%, dizziness, sleepiness at about 5%. More disappear within 1d.