The most effective prescription antacids are proton pump inhibitors, H2 blockers and pro-motility agents, according to WebMD. Proton pump inhibitors and H2 blockers work by inhibiting acid production. Promotility agents work by stimulating the muscles of the gastrointestinal tract, preventing acid from remaining in the stomach too long.
Examples of proton pump inhibitors include rabeprazole, esomeprazole and lansoprazole, as listed by WebMD. Proton pump inhibitors should be taken an hour before eating. Examples of H2 blockers include cimetidine, famotidine and ranitidine. Common side effects of H2 blockers include diarrhea, headache and runny nose. An example of a common promotility agent is metoclopramide.