How to manage the initiation of apomorphine therapy without antiemetic pretreatment: A review of the literature

Introduction: Pretreatment with the antiemetic trimethobenzamide has been recommended practice in the United States (US) to address the risk of nausea and vomiting during initiation of apomorphine treatment. However, trimethobenzamide is no longer being manufactured in the US, and despite the recent update to the US prescribing information, there may be uncertainty regarding how to initiate apomorphine. Methods: To better understand why antiemetic pretreatment was recommended and if it is necessary when initiating apomorphine therapy, we performed a literature review of subcutaneous apomorphine therapy initiation with and without antiemetic pretreatment in patients with PD. Results: Three studies were identified as providing relevant information on antiemetic prophylaxis with initiation of injectable apomorphine. The first study demonstrated that nausea was significantly more common in patients who received 3-days of trimethobenzamide pretreatment compared with those who did not, while the primary endpoint of second study found no significant effect on the binary incidence of nausea and/or vomiting on Day 1 of apomorphine treatment. In the third study, which used a slow titration scheme for apomorphine, transient nausea was reported in just 23.1% of the antiemetic nonusers. Conclusions: Based on the reviewed trials and our clinical experience, we suggest that subcutaneous apomorphine therapy can be initiated using a slow titration scheme without antiemetic pretreatment.