Serotonin Receptor Antagonists Less Successful at Controlling Nausea than Vomiting: Presented at MASCC-ISOO
By Paula Moyer
GENEVA, SWITZERLAND -- July 14, 2005 -- Serotonin receptor antagonists, also known as 5 HT-3 antagonists, are less effective at controlling chemotherapy-induced nausea than they are at controlling vomiting, researchers reported here on July 2nd.
Investigators presented their findings at the 17th International Symposium of the Multinational Association of Supportive Care in Cancer and the International Society for Oral Oncology (MASCC-ISOO).
Although breakthrough vomiting is experienced by a small minority of patients who take medications in this drug class before chemotherapy, nearly half still experience nausea, said Jane Hickok, MD, MPH, Research Assistant Professor, University of Rochester Cancer Center, Rochester, New York, United States.
The conventional belief is that 5 HT-3 antagonists greatly improve control of chemotherapy-induced nausea and vomiting. Many studies have shown that patients who are treated with these agents are less likely to vomit, particularly if these drugs are given with dexamethasone on the day that they received chemotherapy. However, the literature is less clear on the effect of 5 HT-3 antagonists on nausea.
Therefore, Dr. Hickok and colleagues recruited 226 patients who self-reported the occurrence and severity of nausea and number of vomiting episodes during 4 daily time periods over the course of 4 days, starting with the day of chemotherapy. The time periods were morning, afternoon, evening and night.
All patients in the study were chemotherapy-naïve. When they received their first course of chemotherapy containing doxorubicin, they also received one of three 5-HT3 receptor antagonists: ondansetron (Zofran), granisetron (Kytril), or dolasetron (Anzemet). These medications were taken along with dexamethasone in standard doses on the day of treatment: 8 mg of ondansetron; 3 mg IV before chemotherapy of granisetron; up to 100 mg 1 hour before treatment of dolasetron; 8 mg IV followed by 4 mg orally of dexamethasone. They also took the 5-HT3 receptor antagonist on days 2 and 3.
The overwhelming majority of study subjects were women (96%), white (90%), and being treated for breast cancer (95%). They were an average of 54 years old. Among these subjects 34% used a rescue medication in addition to their serotonin receptor antagonist. Only 3% received dexamethasone on Days 2 or 3.
The investigators found that 12% or fewer of patients reported vomiting. However, at least 40% reported nausea at each time point. The findings showed that treatment with serotonin receptor antagonists produces significantly better protection against vomiting than against nausea (P < .001).
The researchers stressed that treatment of nausea remains elusive and that nausea is a debilitating intrusion into patients' performance of normal daily activities and affects their quality of life and may also compromise treatment adherence.
They called for further research to find effective ways to reduce chemotherapy-induced nausea.
[Presentation title: Differential Effects of Serotonin Receptor Antagonists on Nausea (N) and Vomiting (V) Associated with Moderately Emetogenic Chemotherapy. Abstract 27-204]
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