Posted by Ritch on March 21, 2005, at 23:16:52
In reply to Re: Tegretol, Dilantin..... » Ritch, posted by ed_uk on March 21, 2005, at 13:43:49
> Hi Mitch!
>
> >Yes, there is a new one called Equitrol.
>
> We've got three different controlled release carbamazepine brands here, we don't have Equitrol though, it sounds good. Do you think you'll try it soon?Actually, not *soon*, if at all really. After reading about all the hassles with drug-drug interactions... I'm thinking I'll just stay on the Depakote, by itself.
>
> >I'm wondering since I'm so med sensitive, that I could get by with just 100mg/day
>
> Most people need 200-500mg phenytoin for epilepsy, the plasma concentration of phenytoin is *not* proportional to dose. At doses <200mg, the plasma conc is often very low indeed. It's difficult to to say though because you're on Depakote. Depakote often raises the plasma conc of phenytoin- but may lower it in some people!! Also, phenytoin often lowers the plasma conc of Depakote. During the period of dose titration of phenytoin, measuring the plasma conc is important because small dosage increases (eg 25mg) can produce large increases in plasma conc, this is because the relationship betweeen dose and plasma conc is non-linear. Phenytoin's also got quite a narrow therapeutic index, toxicity may occur if the plasma conc is too high. With phenytoin, it's often best to avoid generics and to always use the same brand name, different brands may have slightly different bioavailabilities, this can sometimes be enough to produce a clinically significant change in the plasma concentration.
>
> Best regards,
> Ed.
>
>Wow, there's another drug-drug interaction biggie. My Mom was on on the 100mg phenytoin-sodium Kapseals made by Parke-Davis. She also took phenobarbitol with it. Hey, isn't there a non-linear pharmacokinetic thing with Depakote as well, with regards to plasma protein binding or something? Something to do with *other* meds that bind highly to plasma protein? What other meds do that? ..
poster:Ritch
thread:471753
URL: http://www.dr-bob.org/babble/20050317/msgs/473849.html