what is the enzyme thing with DXM that some people dont have? is it when your LACTOSE INTOLERANT that you shouldnt take DXM or something else? clear this up for me if you could. soon
DXM is metabolized by the cytochrome P450 enzyme pathway in the liver. Lactose intolerance probably has no relation at all to DXM metabolism.
You would know after taking it. There are probably other ways to test, since the P450 pathway metabolizes many other drugs and chemicals, not just DXM, but I couldn't name any of those methods off the top of my head. The deficiency seriously reduces the rate at which DXM is metabolized such that it stays active in the body much longer than normal (several days). This causes a laundry list of unwanted side-effects in the P450-deficient individual, which vary person-to-person from moderate to extremely severe. Part of the reason that people on antidepressants should not take DXM is that most antidepressants, such as sertraline (Zoloft) for example, partially inhibit the cytochrome P450 pathway. Although it may not always be enough to cause serious harm (though that point itself is debatable), many people report undesirable effects from combining DXM with antidepressants. And, of course, individual reactions can vary greatly. Furthermore, the risk of developing the oftentimes life-threatening "serotonin syndrome" is significantly elevated.
