Heartburn Relief may cause an allergic reaction in some patients. This reaction could be severe and should be reported to your local physician if hives, facial swelling, or breathing troubles occur. The following side effects should also be reported to medical personnel as soon as possible: abnormal bleeding or bruising, confusion, numbness, jaundice, rapid heartbeats, hallucinations, or seizures. Other side effects that are not as severe in nature include nausea, dry mouth, dizziness, headaches, cramping of muscles, joint pains, mood changes, vomiting, weakness, diarrhea, or constipation.