There aren't very many problems that we run into when we combine these drugs with other drugs. They share very nicely in the body with other drugs. The only exception to that - and it's a fairly mild one - involves omeprazole and esomeprazole. These are the only two PPIs that inhibit the metabolism of the enzyme 2C19, which can therefore affect the metabolism of other drugs a patient may be taking that are also metabolized by 2C19. None of the other proton pump inhibitors have that particular feature, so that's a bit unique to omeprazole and esomeprazole.

All of the compounds, because they change the pH in the stomach, can affect the absorption of some other drugs. Again, the list is fairly short, although not a lot of studies have been done. But there are some drugs where there may be a marked reduction in the absorption. Some of the antifungal agents, for example, and that can be a problem with any of the proton pump inhibitors.

All the proton pump inhibitors also look to be very safe, long-term. Probably the longest data we have now is approaching 10 to 12 years with some of these compounds and there just hasn't been any evidence at all - and people have certainly looked for it - to suggest that these drugs present a long term safety issue for most patients. So I think we have, in total, a group of drugs that are very effective and very safe, and yet have some interesting differences that can be employed creatively to produce the best response in any given patient.