I think that you should still be able to burp if taking anti gas medication. Anti-gas medication should alleviate problems at the other end of things. So if you you drink a pop or something that makes you burp then you are fine.
Often, burping is caused by the stomach becoming 3/4ths full, releasing a pocket of air within the stomach and up the esophagus. Taking in less carbonated products and eating until satisfied should help.