First time I got the rash, Eucerin calming cream worked. Benadryl, hydrochortosone did not. No drug interactions there. I currently have rash again, and NOTHING worked. I finally TOLD my Dr. To prescribe Fluocininide. Again no interactions there. It has worked great. It is not completely gone, but is subsiding and itch is so much better. Don't know about drug interactions for your antinausea, but Zofran works great, it causes annoying headache occasionaly but no drowsiness.