Q: How it could be determined to administer drug before or after plasmapheresis? 

 Answer: Plasmaphresis is frequently performed in ICU for various immunologic, infectious, drug overdose and metabolic diseases. If it is a lipophillic drug, it should be administer after plasmaphresis, as they are highly protein-bound, and have a small volume of distribution.


Reference: 

Kale-Pradham PB, Woo MH. A review of the effects of plasmapheresis on drug clearance. Pharmacotherapy. 1997;17:684-695