(Update: His kidney doctor has confirmed that it was, in fact, Imbruvica that most likely caused the low sodium issue and that they will be taking my dad off of it. He's doing much better now that his sodium level is increasing. )
All right, a few days ago I posted about how my dad had just started Imbruvica and how it seemed to be hitting him pretty hard.
On Tuesday he went to see his oncologist about some of his concerns. After some blood work, it was determined that his sodium levels were dangerously low and he was admitted to the hospital. Thankfully, we aren't looking at tumor lysis or (at least so far) any kidney problems. Right now the doctors don't really know what caused it, although he's been admitted for low sodium before, just not this low.
The doctor said that low sodium is not a common side effect with Imbruvica. I'm wondering if anyone else has had the issue, or perhaps someone's had Imbruvica interact poorly with their other medications and have had a similar issue, or even if you've had a history of low sodium and have encountered this issue.
With all of that said, I encourage you to be extra vigilant for signs of low sodium. I know it's not common with Imbruvica, but the drug does tend to cause a lot of fluid loss.
Update: His kidney doctor has confirmed that it was, in fact, Imbruvica that most likely caused the low sodium issue and that they will be taking my dad off of it. He's doing much better now that his sodium level is increasing.
Zanubrutinib and water intake and sodium level
Imbruvica and BM issues
Imbruvica 
Imbruvica and Heart Issues
Muscle cramps on Imbruvica
