Twenty-four-hour intragastric pH-metry: H2-receptor antagonist restoration of nightly gastric spontaneous alkalinization in duodenal ulcer healing.

Continuous 24-hour intragastric pH monitoring allows the evaluation of spontaneous late night gastric alkalinization phenomenon (SNA). This nocturnal increase of intragastric pH is strongly evident in healthy volunteers but is insignificant in patients with active duodenal ulcer. Gastric acidity was monitored by 24-hour continuous pH-metry in nine patients with active duodenal ulcer disease before and after two weeks of therapy with ranitidine. A twice daily dose of the drug (150 mg at 08.00 h and 150 mg at 20.00 h) was orally administered to each subject. Before treatment the ulcer patients did not show the SNA phenomenon, but the therapy led it to reappear. Ranitidine significantly reduced the time during which the gastric acidity was lower than 4 pH units; moreover the drug was effective on the ulcer healing during a period as brief as two weeks of therapy. At least a complete healing of the duodenal ulcer could be seen in patients whose overall gastric acidity time was reduced almost to the 40% of the pre-treatment value, meal times excluded from the pH-metric calculation.