What is the optimal prophylaxis regimen to use prior to a selinexor based regimen in the treatment of multiple myeloma for nausea and electrolyte abnormalities? 

The official Karyopharm guidelines for nausea are as follows: NK-1R antagonist OR a combination of 5-HT3 antagonist AND olanzapine. So the details are:

a) All patients should receive ondansetron 8 mg or equivalent, unless contraindicated, orally 1 hour before each dose of selinexor and q 8 hours for total of 3 days post selinexor for the first 2 cycles of the study. Olanzapine 5 mg PO or equivalent for 3 days after XPOVIO for the first 2 cycles of the study or longer if needed; OR

b) An NK1 recept...

A once-weekly (as opposed to twice-weekly) selinexor dosing will surely help to cut down on side effects, especially nausea and vomiting. It's also important to educate patients thoroughly that even though it is a pill, it is still once a week and not daily (unlike lenalidomide for example), and should not be taken all at once. Our practice is to 'double cover' with anti-emetics. We start all patients with a 5ht3 antagonist like ondansetron. The second drug we typically use is olanzapine and we ...