When a person becomes infected with a norovirus, the virus begins to multiply within the small intestine. After approximately 1 to 2 days, norovirus symptoms can begin. This period between the norovirus transmission and the start of symptoms is the  norovirus incubation period ..In some cases, the norovirus incubation period can be as short as 12 hours.his period between the norovirus transmission and the start of symptoms is the  norovirus incubation period .. In some cases, the norovirus incubation period can be as short as 12 hours.
Drug type: Fluorouracil is an anti-cancer (antineoplastic or cytotoxic) chemotherapy drug. Fluorouracil is classified as an antimetabolite.. (For more detail, see How Fluorouracil Works section below). What Fluorouracil Is Used For: 1  Colon and rectal cancer. 2  Breast cancer.
Drugs used to treat colorectal cancer. Some common drugs used for colorectal cancer include: 5-Fluorouracil (5-FU), which is often given with the vitamin-like drug leucovorin (also called folinic acid) or a similar drug called levo-leucovorin, which helps it work better. Capecitabine (Xeloda), which is in pill form.