Longevity
UpdatedHow long after Xtandi has reduced PSA levels to zero or almost zero does it take for PSA levels to start to rise and I will have to find another step in treatment?
1 Reply
Hi Marlee,
I'll be honest, I don't know anything about PSA levels or what that stands for medically, BUT, looking at the estimated half life of Xtandi (enzalutamide) you can get a really good idea of how long it will be working in your body since your last dose.
According to The University of Utah, the mean half life of Xtandi is 5.8 days with a broad range of anywhere between 2.8 – 10.2 days.
So if Xtandi reduced your PSA levels shortly after ingestion, it will take about 5 days for half of that dose to be eliminated from your body; and then another 5 days for half of that remaining half to be eliminated, and so forth. So in theory the recommended dose of 160 mgs will have dwindled down to 2.5mg by the 30th day after your last dose. I'd imagine that at this point in time, Xtandi wouldn't be having the same level of effectiveness on your PSA levels as when you first took it; and therefore causing your PSA levels to gradually rise. It's a little hypothetical but after doing the math this seems to make the most sense to me when it comes to figuring out how long it's having an effect on your PSA levels.
Hope this helps!