Evaluation of Ropinirole versus Apomorphine for Emesis Induction in Dogs

To compare the efficacy of ropinirole (ROP) eye drops and IV apomorphine (APO) for inducing emesis in dogs in an emergency setting and to compare the adverse effects of these two drugs.

Prospective, randomized, clinical trial between October 2021 and March 2023.

Two private specialty referral centers.

One hundred thirty-two client-owned dogs with known or suspected foreign material ingestion.

Dogs were randomly assigned to receive ROP (n = 63) or APO (n = 69) to induce emesis. If emesis did not occur within 20 min, subjects were re-dosed with the same medication and dosage. The reason for emesis, success, time to first emesis, number of emetic events, and need for rescue antiemetic were evaluated. Heart rate, respiratory rate, and temperature were tracked at time 0 and at 20 and 40 min. Adverse events were categorized into major events (e.g., tachycardia, hyperthermia, tachypnea), minor events (e.g., sedation, ocular irritation), and protracted vomiting (vomiting past 30 min).

ROP's first-dose success was 81% (51/63) compared with APO's 99% success (68/69) (p < 0.001). The median time to the first emetic event was 8.6 min in the ROP group and 1.6 min in the APO group (P < 0.001). Antiemetic rescue was required in 37% (23/63) of dogs receiving ROP and 0% (0/69) of dogs receiving APO (P < 0.001). The major adverse event frequency between groups was not different (P = 0.604); however, the minor adverse event frequency was statistically significant (P = 0.011).

ROP had a lower first-dose emetic success rate, a longer median time to the first emetic event, an increased occurrence of minor adverse events, and a higher frequency of protracted vomiting necessitating rescue therapy. These findings suggest APO is a clinically superior emetic agent for dogs presenting to the emergency department requiring rapid decontamination.