Posted by jane d on October 10, 2002, at 1:13:06
In reply to Re: there is no Lexapro-Toprol interaction /bottom » jane d, posted by pharmrep on October 8, 2002, at 0:43:06
You know I actually re-downloaded the prescribing information from the Lexapro site to see if it had been changed and you were looking at a different version. You aren't. So i'll try to show you what I saw there that you apparently didn't see.
The prescribing information is from: http://www.lexapro.com/home/default.asp under prescribing information.
PHARMREP SAID:
>>Did you read the Package Insert? it states "coadministration of lexapro and metoprol had no clinically significant effects on blood pressure or heart rate." Under the "drug interactions" section...10+ "common" meds are mentioned to show that they were specifically looked at...and none of them had "interactions." So what are you referring too?Sorry Pharmrep. We seem to have some misunderstandings here but I'll try to explain. I'm talking here about the drug interactons section that starts on page 4. One thing I found interesting is that metoprolol was NOT listed alongside that list of drugs that are not supposed to interact significantly (and it actually doesn't always say that if you read closely). They are lumped together and then you get a paragraph explaining that there is some 2D6 inhibition and saying "caution is indicated in coadministration of escitalopram(lexapro) and drugs metabolized by CYP2D6".
(By the way, if you don't really understand the CYP 450 enzyme system this is a great place to ask. There are a lot of posters here who are great at explaining that kind of thing. I'm not one of them unfortunately.)
The drugs metabolized by CYP2D6 include Toprol and, in fact, Toprol now gets it's own section. It does indeed say that there was a study where giving Toprol and Lexapro at the same time did not increase the patients heart rate or blood pressure. But it also says that this raises the level of Toprol found in the blood. And that increased levels of Toprol may effect how the Toprol works. The one thing it does NOT say is that there is NO interaction. It makes me a little nervous that you are taking a position that your own employer was unwilling to (or perhaps not legally permitted) to take.
By the way, the post by JLM also describes a possible interaction of a totally different kind (and a quick check of medline will get you more of the same). Remember the CYP 450 system is only one possible source of interactions.
Please don't take this as an attack on Lexapro or a statement that no one can combine the drugs at all. If I were facing this choice myself I might decide that I cared about the study on heart rate more than the one on blood levels - although I'd want to see the study, how many people were involved, and think about what other drugs I was taking before making that decision. I don't have a problem with you pointing out both facts or even with you giving an explanation for why you would give one more weight than the other. That's not the same as providing only half the facts or saying "there is no interaction" which doesn't help anyone make their own decision.
Jane
PS. Does anyone have an opinion on whether metoprolol should be counted as a CNS drug. I doesn't seem to be listed as one but it seems to me that it should be.
poster:jane d
thread:109458
URL: http://www.dr-bob.org/babble/20021006/msgs/123022.html