Hello and thanks for your enquiry,

Unfortunately, we can't give you specific advice on the itching. Sometimes a light sedative can help. But do let the hospital team know about the level of ongoing symptoms that are being experienced. Specific questions about medications are best answered by a trained pharmacist. The current online guidance about this drug says,

Take this medication before a meal and/or at bedtime, and try to take any other medications at least 1 hour before or 4 hours after you take cholestyramine because cholestyramine can interfere with their absorption. 

I hope that this helps,

Best wishes,

Vanda