BACKGROUND: The rapid onset and symptomatic response to histamine-2 receptor antagonists prior to the pharmacological effect on acid secretion suggests a different mechanism of action. AIM: To determine if ranitidine decreases oesophageal sensitivity to chemical and mechanical stimulation, potentially via oesophageal histamine receptors. METHODS: A total of 18 patients with functional heartburn received oral ranitidine 150 mg b.d. or placebo for 7 consecutive days in a double-blind randomized crossover design and underwent Barostat balloon distention and Bernstein acid infusion on study day 1 (90 min postdose) and study day 7. First sensation and pain were recorded and pain severity was rated on a 5-point Likert scale and a 100 mm visual analogue scale. Least square mean values were generated and one-tailed t-tests were performed. RESULTS: After a single dose of ranitidine 150 mg, time to pain with oesophageal acid infusion was increased by 29% (P < 0.05) and visual analogue scale and Likert scores were decreased by 20% (P < 0.06) and 23% (P < 0.02), respectively compared with placebo. After 1 week of ranitidine, positive alterations in sensory parameters persisted. Balloon distention sensory parameters were not altered by ranitidine. CONCLUSIONS:Ranitidine significantly decreased oesophageal sensitivity to acid. Failure of ranitidine to improve balloon sensory parameters supports existence of multiple sensory pathways in the oesophagus.
RCT Entities:
BACKGROUND: The rapid onset and symptomatic response to histamine-2 receptor antagonists prior to the pharmacological effect on acid secretion suggests a different mechanism of action. AIM: To determine if ranitidine decreases oesophageal sensitivity to chemical and mechanical stimulation, potentially via oesophageal histamine receptors. METHODS: A total of 18 patients with functional heartburn received oral ranitidine 150 mg b.d. or placebo for 7 consecutive days in a double-blind randomized crossover design and underwent Barostat balloon distention and Bernstein acid infusion on study day 1 (90 min postdose) and study day 7. First sensation and pain were recorded and pain severity was rated on a 5-point Likert scale and a 100 mm visual analogue scale. Least square mean values were generated and one-tailed t-tests were performed. RESULTS: After a single dose of ranitidine 150 mg, time to pain with oesophageal acid infusion was increased by 29% (P < 0.05) and visual analogue scale and Likert scores were decreased by 20% (P < 0.06) and 23% (P < 0.02), respectively compared with placebo. After 1 week of ranitidine, positive alterations in sensory parameters persisted. Balloon distention sensory parameters were not altered by ranitidine. CONCLUSIONS:Ranitidine significantly decreased oesophageal sensitivity to acid. Failure of ranitidine to improve balloon sensory parameters supports existence of multiple sensory pathways in the oesophagus.