ヒスタミンH2受容体拮抗薬の適応と効果

The Indication and Efficacy of H2-Receptor Antagonist

要旨　H₂ブロッカーは強力な酸分泌抑制作用を有し，潰瘍治癒促進作用が証明されている．低酸例でも有効との報告もあるが，十二指腸潰瘍，併存潰瘍，胃角部より肛門側の胃潰瘍など酸分泌亢進例が主な適応である．従来の多剤併用療法に比べ十二指腸潰瘍の治癒率が高く，外来では6週治癒率に有意差を認めた（従来法 55.5％，H₂ブロッカー 82.9％）．入院治療例では1，2，3，4週のいずれも高い治癒率が得られた．胃潰瘍では制酸剤，粘膜防御剤，多剤併用のいずれよりも4週以降の治癒率が高いことが証明された．また，H₂ブロッカーは胃潰瘍面積を他の薬剤に比べ早期に縮小させることがわかった．

　1. Review of the efficacy of H₂-receptor antagonist. The efficacy of H₂-receptor antagonist (H₂-blocker) for peptic ulcer was reported in many articles. In the placebo-controlled studies, all cimetidine regimens were associated with a statistically significant increase in the frequency of ulcer healing. Reports of multi-clinic double blind studies with three H₂-blockers (cimetidine 800 mg, ranitidine 300 mg, famotidine 40 mg daily) in Japan were equally more effective for peptic ulcer healing than gefarnate.

　2. Open trials with H₂-receptor antagonist and other anti-ulcer drugs for peptic ulcer patients in Kitasato University Hospital. Fifty-five outpatients with duodenal ulcer were treated with H₂-blocker or con-ventional medical treatment. Endoscopy was performed at intervals of three and six weeks. Healing rates at three and six weeks were 41.7％ (15/36), 82.9％ (29/35) with H₂-blocker and 23.5％ (4/17), 55.5％ (10/18) with conventional treatment. 131 cases gastric ulcer patients were treated with H₂-blocker, antacid, so called mucosal protector, conventional regimen and H₂-blocker with other anti-ulcer drugs. Healing rates at two, four, six and eight weeks with various drugs were compared retrospectively. Healing rates with H₂-blocker were as follows: 49.7％ (22/54) at four weeks, 69.2％ (27/39) at six weeks, 79.5％ (35/ 44) at eight weeks respectively. The efficacy of H₂-blocker was superior to any other drugs at four and six weeks.

　3. Indication of H₂-receptor antagonist for peptic ulcer. H₂-blocker treatment is necessary in the treatment of all duodenal ulcers, all combined ulcers, and gastric ulcers located in the angle and pyloric antrum.