Hi Mike,
Have you tried all the usual ways to decrease herxing- charcoal, baking soda/ epsom salt bath, apple citrus pectin, etc?
Also, is medical marijuana legal in your state?
Taking Ibuprofen and benadryl every 4-6 hours can also be helpful with IVIG, you should start them as soon as you begin your infusion and continue for 48-72 hours if the IVIG makes you herx a lot.
Those are the things that work best for us.