Intranasal and intravenous apomorphine outperform ropinirole ocular drops for induction of emesis in dogs within ten minutes: a randomized, controlled clinical trial.

Objective: The primary goal was to compare the efficacy of administration of apomorphine (APO) administered by intranasal (IN), transconjunctival (TC), SC and IV routes with ropinirole eye drops for induction of emesis in dogs with a secondary goal to evaluate the time of emesis as well as difficulty in administration.

Animals: 125 client-owned dogs.

Methods: Dogs were randomly enrolled between October 1, 2021, and March 30, 2022, into groups of 25: IV APO, IN APO, TC APO, SC APO, and ropinirole eye drops. The IV, SC, and TC groups were dosed at 0.03 mg/kg, the IN group was dosed at 0.06 mg/kg, and the ropinirole group was dosed according to manufacturer guidelines. Data collected included success rate of emesis within 600 seconds, time to emesis, time to administer, and difficulty score. Results were compared to IV with P values and CIs being adjusted for multiple comparisons.

Results: Emesis was successful within 600 seconds using IV APO in 22 of 25 dogs. By comparison, IN APO induced emesis in 18 of 25 dogs (P = .63). Ropinirole (14/25), SC APO (6/25), and TC APO (4/25) were significantly less successful (P = .047, P = < .001, and P < 0.001, respectively). When emesis was successful, it occurred most rapidly with TC APO, followed by IN APO and then ropinirole. It was most difficult to administer IV APO and TC APO.

Clinical relevance: Similar to IV APO, IN APO was a rapid, easy, and effective method of inducing emesis in dogs and should be considered when IV administration is not possible. Ropinirole was easy to administer but successfully induced emesis less reliably within a 10-minute timeframe. APO administered TC using the commercially compounded injectable formulation was ineffective.