A study was conducted by Robinson and colleagues to look at integrated gastric and integrated esophageal acidity in people experiencing meal-induced heartburn, who self-medicated with placebo, low-dose ranitidine, antacid alone, or ranitidine with antacid, for relief of heartburn.

The 26 study participants had heartburn over four times in a week for at least 2 months, which responded to antacids. Gastric and esophageal pH were evaluated for 1 h prior to, during, and 4.5 h after a meal over 0.5 h. Heartburn severity was evaluated at 15-min intervals starting at the end of meal. Each participant was randomized to receive placebo, ranitidine, calcium carbonate, and ranitidine plus calcium carbonate.

• Investigators noted a close temporal relationship between heartburn and esophageal acidity.
• Most esophageal acid exposure was noted during a 90-min period starting about 45 min after the end of the meal. Over this duration, the gastric acid concentration was below 5% of maximal.
• Ranitidine significantly reduced gastric acidity, while the antacid significantly reduced esophageal acidity.
• Ranitidine along with antacid led to a significant reduction in both gastric and esophageal acidity.
• Ranitidine plus antacid also significantly reduced heartburn severity.

In meal-induced heartburn, low-dose ranitidine with an antacid can effectively reduce gastric and esophageal acidity and heartburn severity.

Source: Robinson M, Rodriguez-Stanley S, Ciociola AA, et al. Synergy between low-dose ranitidine and antacid in decreasing gastric and oesophageal acidity and relieving meal-induced heartburn. Aliment Pharmacol Ther. 2001 Sep;15(9):1365-74.