Moderate to severe nausea in radioactive iodine (RAI) therapy is associated with the RAI dose per body weight and was not prevented by ramosetron.

To retrospectively analyze the individual risk factors for radioactive iodine (RAI)-associated nausea and vomiting, and to examine the anti-emetic effect of ramosetron (5-hydroxytryptamine-3 receptor antagonist) in RAI therapy. Patients with differentiated thyroid carcinoma who underwent first-time RAI therapy at Nagasaki University Hospital between January 2009 and 2013 were included (N = 81). As a routine treatment, all patients were administered 30 mg of domperidone per day. Patients who underwent RAI therapy between April 2011 and January 2013 were also administered 0.1 mg of ramosetron per day in addition to domperidone. Nausea and vomiting were evaluated based on Common Terminology Criteria for Adverse Events version 4.0. RAI-associated nausea and vomiting of any grade were seen in 37.0 and 6.2 % of patients in total, respectively. Moderate to severe nausea (grade 2–3) was seen in 22.2 % of patients and associated with the dose of RAI per body weight (odds ratio = 1.046, p = 0.013), but not with the use of ramosetron, in multivariate logistic regression analysis. We have identified the dose of RAI per body weight to be an individual risk factor associated with moderate to severe RAI-associated nausea. This study failed to show that the combined use of ramosetron and domperidone reduced the frequency of RAI-associated nausea and vomiting.