Hi Sue,
It's possible you're having an allergic reaction to the dilutant being used; here's a quote from the Genentech web page regarding dosage instructions for Herceptin, along with a link to the page:
"...If the patient has known hypersensitivity to benzyl alcohol, HERCEPTIN must be reconstituted with Sterile Water for Injection (see
PRECAUTIONS). HERCEPTIN WHICH HAS BEEN RECONSTITUTED WITH SWFI MUST BE USED IMMEDIATELY AND ANY UNUSED PORTION DISCARDED. USE OF OTHER RECONSTITUTION DILUENTS SHOULD BE AVOIDED..."
Genentech/Herceptin Page
http://www.gene.com/gene/products/in...administration