During the first trimester, hormonal changes often cause severe indigestion. Since she is vomiting her current syrup, safe generic alternatives include calcium carbonate chewable tablets, which are often easier to keep down than liquids. Magnesium hydroxide or aluminium hydroxide antacids are also generally safe. For stronger relief, generic H2 blockers like famotidine can be used. To help manage symptoms, she should eat small, frequent meals and avoid lying down immediately after eating. Please consult her obstetrician before starting any new medication, especially to evaluate the chest pressure and ensure her safety.