Comparing Cimetidine and Zantac
This is probably the most important difference between the two medications. Cimetidine is much more likely to cause drug interactions than any other H2 blocker, including Zantac. Cimetidine affects the way the liver metabolizes many medications, leading to increased levels of other medications in the blood (see Tagamet Drug Interactions for more information). Zantac is much less likely to interact with other medications.
In many ways, there is little difference between the two medications. They both work the same way. They are both available with or without a prescription. Both cause similar side effects (see Zantac Side Effects and Tagamet Side Effects), and they have very similar warnings and precautions. Both are available in tablet and liquid forms (although Zantac is also available in orally disintegrating tablets). They both are available in generic versions.
Although the H2 blockers are all very similar, some people may find that one works better than the others. As long as drug interactions are not a concern (if you are not taking other medications), there are probably no important differences for the average person. However, if you are taking other medications, it is a good idea to ask your healthcare provider whether cimetidine or Zantac would be better for you.