An experimental study of consecutive administration of ropinirole and apomorphine for emesis induction in dogs

OBJECTIVE

To study the safety and effectiveness of consecutively administered ropinirole and apomorphine (both dopamine 2-like receptor agonists) for emesis induction in dogs.

DESIGN

Prospective, crossover study design.

SETTING

Institutional animal research facility.

ANIMALS

Six healthy male purpose-bred Beagle dogs.

INTERVENTIONS

Each dog received 4 treatments: (1) apomorphine infusion (21 μg/kg) over 30 minutes + ropinirole eye drops (3.75 mg/m2 ); (2) ropinirole infusion (108 μg/m2 ) over 30 minutes + apomorphine SC (100 μg/kg); (3) apomorphine SC (100 μg/kg) + ropinirole eye drops (7.5 mg/m2 ) after 30 minutes; and (4) ropinirole eye drops (7.5 mg/m2 ) + apomorphine SC (100 μg/kg) after 30 minutes. Infusions were administered via a catheter instrumented in the cephalic vein. Eye drops and SC injections were administered as described in the product inserts. Blood samples were taken for ropinirole and apomorphine concentration analysis before dosing and periodically following administrations. The washout period between the treatments was 5-7 days.

MEASUREMENTS AND MAIN RESULTS

Number of vomits and clinical signs were recorded. Alertness and heart rate were monitored in conjunction with blood sampling. The average number of vomits varied between 4.3 and 8.8 (range 1-16) following treatments. Signs of nausea, vomiting, and lethargy were seen in all individuals without significant differences between treatments. Moderate to marked, transient increase in heart rates was detected in all treatments. Infrequent noted side effects included ocular hyperemia, blepharospasms, and muscle tremors. Prior treatment with apomorphine significantly decreased the absorption of ropinirole eye drops.

CONCLUSIONS

The safety and efficacy profiles of this experimental study support that ropinirole and apomorphine could be administered consecutively in cases where the treatment using 1 substance has resulted in an incomplete evacuation of the stomach contents, and the attending veterinarian considers the use of a different agent to have benefits that outweigh the risks.

Induction of emesis with apomorphine using a novel gingival administration method in dogs

OBJECTIVE

To describe a novel method of inducing emesis in the dog using gingival administration of apomorphine, compare the efficacy of inducing emesis with gingival apomorphine to conjunctival apomorphine, and describe adverse effects associated with the gingival route.

DESIGN

Retrospective study from January 2017 to September 2018.

SETTING

Independent all-hours primary and secondary emergency and critical care referral center.

ANIMALS

Five hundred fifty-eight client-owned dogs.

MEASUREMENTS AND MAIN RESULTS

The medical records of dogs presenting for induction of emesis were searched. Dogs receiving either gingival or conjunctival apomorphine were included in the study. A short online survey was sent to clients whose dogs received gingival apomorphine. Apomorphine was administered conjunctivally in 430 (77.1%) dogs and gingivally in 128 (22.9%) dogs. There was no difference between route of administration and success of emesis (p = 0.29). A total of 14 clients responded to the survey, and diarrhea, lethargy, hyperactivity, and sedation were reported as adverse effects of gingival apomorphine administration. No clients sought veterinary attention for any of the adverse effects reported.

CONCLUSIONS

Gingival administration of apomorphine is easy, appears to be safe, and is an effective method of inducing emesis in the dog. Gingival administration of apomorphine may be considered in cases where parenteral administration is not feasible and could replace conjunctival administration in compliant dogs.

Evaluation of subcutaneous versus intravenous administration of apomorphine for induction of emesis in dogs

OBJECTIVE

To prospectively compare the effectiveness and any adverse effects of apomorphine administered SC or IV for induction of emesis in dogs.

ANIMALS

42 client-owned dogs.

PROCEDURES

Dogs for which emesis induction was deemed appropriate by the attending clinician were prospectively randomized to receive apomorphine (0.03 mg/kg [0.01 mg/lb]) either SC (n = 20) or IV (22). Data collected included whether emesis was successfully induced, time from drug administration to emesis, number of emetic events, and adverse events (eg, sedation, protracted vomiting, or other).

RESULTS

Of the 20 dogs given apomorphine SC, 16 (80%) vomited. Of the 22 dogs given apomorphine IV, 18 (82%) vomited. With regard to route of administration, the number of dogs in which emesis was induced did not differ significantly. Median time to the first emetic event was 13.5 minutes (range, 3 to 32 minutes) in the SC treatment group and 2 minutes (range, 1 to 5 minutes) in the IV treatment group; the difference was significant. There was no significant difference in the number of emetic events or frequency of adverse events between the 2 groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Apomorphine administered SC or IV reliably induced emesis in dogs. Compared with SC administration of apomorphine, the time from drug administration to emesis associated with IV administration was significantly shorter, a finding that has clinical importance.

Efficacy of intravenous administration of apomorphine for removal of gastric foreign material in dogs: 495 cases (2010-2015)

OBJECTIVE

To evaluate the efficacy of IV administration of apomorphine for removal of gastric foreign bodies in dogs.

ANIMALS

495 dogs with gastric foreign bodies.

PROCEDURES

Records of a veterinary hospital were searched to identify dogs that received an injectable formulation of apomorphine between January 1, 2010, and July 30, 2015. Dogs with a gastric foreign body that received an IV injection of apomorphine were included in the study. Information extracted from the record of each dog included signalment, type of foreign material ingested, duration between foreign material ingestion and emesis, dose and number of doses of apomorphine administered, and whether emesis occurred and did or did not result in successful removal of the foreign body. Descriptive data were compared between dogs with and without successful foreign body removal.

RESULTS

Emesis with successful foreign body removal was achieved in 363 and 11 dogs after administration of 1 and 2 doses of apomorphine, respectively. Successful removal was more likely for young dogs and dogs that had ingested fabric, leather, or bathroom waste. Successful removal was less likely as the duration between foreign body ingestion and emesis increased and for dogs that received opioids, sedatives, or antiemetics before apomorphine administration. Minor adverse effects were recorded for only 4 dogs.

CONCLUSIONS AND CLINICAL RELEVLANCE

IV administration of apomorphine was a viable alternative for induction of emesis and removal of gastric foreign bodies in dogs. Dogs should be examined as soon as possible after foreign body ingestion and should not receive any medications that might affect apomorphine efficacy.

Ropinirole eye drops induce vomiting effectively in dogs: a randomised, double-blind, placebo-controlled clinical study

There is a need for an effective and safe emetic agent that dog owners could easily administer to their dogs following veterinary advice in cases of potential poisoning. As a response to this need, a randomised, double-blind, multi-site, clinical field study was performed to assess the efficacy, safety and usability of ropinirole eye drops to induce vomiting in dogs. Ropinirole (target dose 3.75 mg/m²) was applied to eyes of 100 dogs, and 32 dogs received placebo. The drug was administered by the dog owner at a veterinary clinic under the supervision of a veterinarian and led to vomition in 95% of the ropinirole-treated dogs within 30 min. The median time to first vomit was 10 min (range: 3–37 min). None of the dogs receiving placebo vomited in this time period. All owners were able to administer the product and 96% of them assessed the administration to be very easy or easy, which was confirmed by the observing veterinarian. Some ocular signs were seen both with ropinirole and placebo, hyperaemia being the most common. All observed signs were transient and in most cases mild. Ropinirole eye drops provided an effective, safe and reliable means to induce emesis in dogs.

The Many Faces of Apomorphine: Lessons from the Past and Challenges for the Future

Apomorphine is now recognized as the oldest antiparkinsonian drug on the market. Though still underused, it is increasingly prescribed in Europe for patients with advanced Parkinson's disease (PD) with motor fluctuations. However, its history is far from being limited to movement disorders. This paper traces the history of apomorphine, from its earliest empirical use, to its synthesis, pharmacological development, and numerous indications in human and veterinary medicine, in light of its most recent uses and newest challenges. From shamanic rituals in ancient Egypt and Mesoamerica, to the treatment of erectile dysfunction, from being discarded as a pharmacological tool to becoming an essential antiparkinsonian drug, the path of apomorphine in the therapeutic armamentarium has been tortuous and punctuated by setbacks and groundbreaking discoveries. Throughout history, three main clinical indications stood out: emetic (gastric emptying, respiratory disorders, aversive conditioning), sedative (mental disorders, clinical anesthesia, alcoholism), and antiparkinsonian (fluctuations). New indications may arise in the future, both in PD (palliative care, nonmotor symptoms, withdrawal of oral dopaminergic medication), and outside PD, with promising work in neuroprotection or addiction.

Safety and efficacy of intravenous administration for tranexamic acid-induced emesis in dogs with accidental ingestion of foreign substances

A prospective observational study was performed in canine clinical medicine to evaluate the emetic action and adverse effects of tranexamic acid. Veterinarians treated 137 dogs with a single dose of tranexamic acid (50 mg/kg, IV) after accidental ingestion of foreign substances. If needed, a second (median, 50 mg/kg; range, 20–50 mg/kg, IV) or third dose (median, 50 mg/kg; range, 25–50 mg/kg, IV) was administered. Tranexamic acid induced emesis in 116 of 137 (84.7%) dogs. Median time to onset of emesis was 116.5 sec (range, 26–370 sec), median duration of emesis was 151.5 sec (range, 30–780 sec), and median number of emesis episodes was 2 (range, 1–8). Second and third administrations of tranexamic acid induced emesis in 64.7 and 66.7% of dogs, respectively. In total, IV administration of tranexamic acid successfully induced emesis in 129 of 137 (94.2%) dogs. Adverse effects included a tonic-clonic convulsion and hemostatic disorder in two different dogs, both of which recovered after receiving medical care. Tranexamic acid induced emesis in most dogs following a single-dose. When a single dose was not sufficient, an additional dosage effectively induced emesis. Overall, adverse effects were considered low and self-limiting.

Efficacy and safety of tranexamic acid as an emetic in dogs

OBJECTIVE

To determine dose dependency of tranexamic acid-induced emesis and the time course of the antifibrinolytic potency of tranexamic acid in dogs.

ANIMALS

10 Beagles.

PROCEDURES

In a dose-escalating experiment, ascending doses of tranexamic acid (10, 20, and 30 mg/kg, IV) were administered at 5-minute intervals until vomiting was observed. In a separate single-dose experiment, ascending doses of tranexamic acid (20, 30, 40, and 50 mg/kg, IV) were administered at 1-week intervals until vomiting was observed. Time to onset of vomiting and number of vomiting episodes were measured in both experiments. In a coagulation experiment, a single 50 mg/kg bolus of tranexamic acid was administered, and blood was obtained 1 hour before and 20 minutes, 3 hours, and 24 hours after administration. Antifibrinolytic potency of tranexamic acid was evaluated by use of a modified rotational thromboelastography method.

RESULTS

Tranexamic acid induced vomiting in a dose-dependent manner. Vomiting frequency was ≤ 2 episodes, and vomiting concluded ≤ 250 seconds after administration. Antifibrinolytic potency of tranexamic acid was significantly higher at 20 minutes following administration, but not different by 24 hours, when compared with the potency measured before administration. No adverse effects were observed in any experiment.

CONCLUSIONS AND CLINICAL RELEVANCE

IV administration of tranexamic acid induced emesis in a dose-dependent manner. The antifibrinolytic potency of tranexamic acid decreased in a time-dependent manner and was resolved ≤ 24 hours after administration. Further studies are warranted to investigate the emetic and other adverse effects of tranexamic acid in dogs of various breeds and ages.