Final answer:
The expected outcome for a GERD patient taking antacids is the neutralization of gastric acid, leading to the relief of stomach upset and pain.
Step-by-step explanation:
A patient with gastroesophageal reflux disease (GERD) taking antacids should expect the desired therapeutic effect of neutralized gastric acid and relief of stomach upset and pain. Antacids work by neutralizing excess stomach acid, resulting in decreased symptoms of heartburn and indigestion. Unlike acid-reducing drugs such as H2-receptor antagonists or proton pump inhibitors, antacids do not reduce the production of acid but instead neutralize the acid already present in the stomach.