Chemotherapy other agents

Fluorouracil-based chemotherapy is the standard of care for the adjuvant treatment of colorectal cancer either as a single agent or, more commonly, in combination with other agents. 5-Fluorouracil (5-FU) alone results in a small improvement in survival that can vary based on the method of 5-FU administration. Studies suggest that protracted or continuous intravenous (IV) 5-FU infusion treatment schedules are more effective than bolus therapy.20... 

In an effort to overcome the lack of solubility, poor penetration across the blood-brain barrier and decreased delivery of conventional systemic agents by a compromised intratumoral blood supply, several studies have evaluated various combinations of BCNU alone or with other agents delivered intraarterally. Unfortunately, response rates and median survival times observed in patients treated with intraarterial chemotherapy have not been significantly different than those seen in patients treated with standard intravenous nitrosurea-containing regimens, while increased rates of toxicity such as leukoen-cephalopathy, retinal injury, edema, myelosuppression, sepsis, and thrombotic complications have been noted (40-46). 

Azathioprine is a derivative of mercaptopurine and, like the parent drug, functions as a structural analog or antimetabolite (Chapter 55 Cancer Chemotherapy). Although its action is presumably mediated by conversion to mercaptopurine, it has been more widely used than mercaptopurine for immunosuppression in humans. These agents represent prototypes of the antimetabolite group of cytotoxic immunosuppressive drugs, and many other agents that kill proliferative cells appear to work at a similar level in the immune response. 

Radiation recall consists of inflammatory reactions triggered by cytotoxic drugs in previously irradiated areas most are skin reactions. Gemcitabine has been implicated in several cases. The authors of a literature review discovered 12 cases of radiation recall caused by gemcitabine and reported a case of myositis in the rectus abdominis muscle of a patient with pancreatic adenocarcinoma as an effect of radiation recall (23). Most of the cases had inflammation of internal organs or tissues and 30% had dermatitis or mucositis. This is different from the effect of other agents that commonly cause radiation recall (anthracyclines and taxanes), with which 63% are skin reactions. Compared with anthracyclines and taxanes, the interval from the completion of radiation therapy to the start of chemotherapy is less with gemcitabine (median time 56 days, compared with 218 days for the taxanes and 646 days for doxorubicin). 

HT3 antagonists are effective for acute nausea, but are not effective for anticipatory nausea, and efficacy is low for delayed nausea. Lorazepam is very effective for anticipatory nausea. Other agents used in chemotherapy-induced emesis are dopamine antagonists, scopolamine, and dronabinol. Antihistamines are generally less effective for chemotherapy-induced nausea and vomiting. 

Indications Antidote for folic acid antagonists, various cancersin combination with other medications Category Antidote Chemotherapy modulating agent Half-life 4-8 hours... 

Chemotherapy. Comparisons of fluorouracil-based regimens alone and in combination with other agents, including trimetrex-ate, raltitrexed, methotrexate, interferon-a, and N-(phosphonacetyl)-L-asparte (PALA), have also been investigated in previously untreated patients with metastatic colorectal cancer. Trimetrexate, raltitrexed, and methotrexate improve response rates and have small effects on progression-free intervals with minimal or no effect on overall survival. The addition of interferon-a or PALA to fluorouracil plus leucovorin increases toxicities and does not improve overall efficacy. 

Catabolic medications or therapies corticosteroids, immunosuppressive agents, radiation, or chemotherapy Other medications diuretics, laxatives, or anabolic steroids Genetic background body habitus of parents, siblings, and family Alcohol or drug abuse... 

The 5-HT -receptor antagonists are the most widely used drugs for chemotherapy-induced emesis. Ondansetron (zofran) is the prototypical drug in this class other agents include granisetron (kytril), dolasetron (anzemet), palonosetron (aloxi intravenous use only) and tropisetron (available in some countries but not in the U.S.). Differences among these agents relate mainly to their chemical structures, 5-HTj receptor affinities, and pharmacokinetic profiles (Table 37-8). 

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