Skipping day 2 antiemetic medications may improve chemotherapy induced delayed nausea and vomiting control: results of two pilot phase II trials.

BACKGROUND: 5HT-3 antagonists and corticosteroids control less than 50% of delayed chemotherapy induced nausea and vomiting (CINV) episodes.

MATERIALS AND METHODS: Two pilot phase II studies were conducted at our institution in which all patients received ondansetron 16 mg and dexamethasone 20 mg before highly and moderately emetogenic chemotherapy on day 1. Patients on study 1 received metoclopramide 10 mg PO q8 h, granisetron 0.5 mg PO QD and dexamethasone 8 mg QD on days 2 and 3, whereas only metoclopramide was continued on the same schedule on day 4. On study 2, patients received the same medications, but no drugs were given on day 2, and the same treatment schedule was given to them but from days 3 to 5 instead. Patients were interviewed on days 1 and 6.

RESULTS: Twenty-one patients participated on each study. There were no significant clinical differences between these two studied populations. Complete CINV control occurred from days 2 to 5 in 23.1% (95% CI: 8 to 47%) on study 1 vs 61.9% (95% CI: 38 to 81%) of the patients on study 2. By logistic regression, complete CINV control was correlated significantly with antiemetic treatment group (p=0.011) even when we considered only patients who achieved complete CINV control during the first 24 h (p=0.031).

CONCLUSIONS: Skipping day 2 antiemetic medications does not seem to worsen delayed CINV control and may even improve it, perhaps by avoiding tachyphylaxis to these medications. A randomized controlled study is in progress to confirm these results.