Emesis In Dogs Research Articles

Use of abdominal thrusts is associated with improved rates of successful emesis induction in dogs.

To evaluate the effect of abdominal thrusts as a synergistic procedure to IV apomorphine administration on the occurrence and rate of onset of successful induction of emesis in dogs. 31 client-owned dogs. Dogs in which induction of emesis via IV apomorphine was prescribed by the attending clinician were prospectively randomized to either receive abdominal thrusts performed by a nurse or clinician or to have no physical interventions performed following IV apomorphine administration. Data collected included signalment, weight, reason for emesis, time from suspected ingestion to presentation, time from the dog's last meal to presentation, dose of apomorphine administered in milligrams, and time from apomorphine administration to emesis. Emesis induction was successful in 14 of 14 (100%) of the dogs in the abdominal thrust group and 13 of 17 (76.5%) in the control group (P = .02). In dogs with successful emesis, median time to emesis was 90.5 seconds (range, 36 to 348 seconds) in the abdominal thrust group and 106 seconds (range, 37 to 360 seconds) in the control group (P = .29). Abdominal thrusts were associated with an increased frequency of successful emesis in dogs following IV apomorphine, but did not shorten the rate of onset of emesis in dogs that vomited. Application of abdominal thrusts may be beneficial in dogs in which emesis is indicated and that do not have a clear contraindication.

Approach to managing chronic vomiting in dogs

Background: Chronic vomiting is a common and, at times, frustrating clinical presentation in our canine patients. Vomiting is considered ‘chronic’ in cases that have gone on for over three to four weeks and the clinical presentation in these cases can vary widely. Given that the list of potential differentials is extensive, a careful and methodical approach to these cases is paramount to successful management.Aim of the article: This article considers an approach to achieving a diagnosis in the chronically vomiting patient, providing readers with the necessary diagnostic toolkit. It also discusses appropriate management strategies to consider in these cases.

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

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. 125 client-owned dogs. 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. 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. 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.

Establishment of a chip digital PCR detection method for canine circovirus

Canine circovirus (CanineCV), which is a new mammalian circovirus first reported in the United States in 2012, mainly causes diarrhea and vomiting in dogs. As CanineCV evolves and new subtypes emerge, there is an urgent need for new detection technologies to improve the sensitivity and detection rates of viruses in complex scenarios. A chip digital PCR(cdPCR) assay was established for the detection of CanineCV in this study. The results showed good reproducibility, specificity and a linear relationship; the minimum detection limit of CanineCV by cdPCR was 6.62 copies/μL, which is 10 times more sensitive than quantitative real-time PCR (qPCR). The qPCR-positive detection rate was 1 %, while CanineCV cdPCR (2.1 %) exhibited a greater positive detection rate. Fifteen complete genomes were sequenced and subdivided into CanineCV-1 and CanineCV-3. In conclusion, we developed a rapid, reliable, and specific cdPCR method for screening and monitoring canine CV.

Effect of preoperative ondansetron on postoperative nausea in healthy dogs undergoing laparoscopic gastropexy and castration

ObjectiveTo investigate if preoperative ondansetron reduces postoperative nausea associated with laparoscopic gastropexy and castration in dogs. Study designProspective clinical study. AnimalsTwenty client-owned, healthy male dogs. MethodsDogs were premedicated with dexmedetomidine (2–5 mcg kg–1) and methadone (0.2–0.5 mg kg–1) intramuscularly. General anesthesia was induced with propofol and maintained with an inhalant anesthetic agent. Dogs were randomized into group S (saline 0.1 mL kg–1, intravenously) or group O (ondansetron 0.2 mg kg–1, intravenously). Plasma and serum were collected before premedication and 3 hours postextubation to measure arginine vasopressin (AVP) and cortisol concentrations. Nausea scoring occurred before and 10 minutes after premedication, immediately after extubation, and at 1, 2 and 3 hours postextubation. Data were analyzed by mixed and split-plot anova with Bonferroni adjustment for the number of group comparisons. Significance was set at p < 0.05. ResultsNausea scores increased over time at 1 (p = 0.01) and 2 (p < 0.001) hours postextubation in both groups compared with before premedication. Median nausea score (0–100 mm) for groups S and O before premedication were 2.5 and 0.5 mm, respectively. At 1 and 2 hours postextubation, group S scored 7.5 and 4.0 mm and group O scored 6.0 and 5.0 mm, respectively. No significant differences in nausea scores within or between groups were observed before premedication and 3 hours postextubation. Cortisol concentrations increased significantly 3 hours postextubation in both groups (p < 0.001) compared with before premedication, with no differences between groups. AVP concentrations showed no significant differences within or between groups. Conclusions and clinical relevancePreoperative intravenous administration of ondansetron (0.2 mg kg–1) did not impact postoperative nausea after laparoscopic gastropexy and castration. Investigation of higher doses of ondansetron on the incidence of postoperative nausea and vomiting in dogs after surgery is warranted.

Metabolism of ropinirole is mediated by several canine CYP enzymes.

Ropinirole has been shown to provoke vomiting in dogs by activating the dopamine D2-like receptors in the chemoreceptor trigger zone. In humans, ropinirole is metabolized primarily by CYP1A2. Corresponding dog CYP1A2 is known to be a polymorphic enzyme which can cause variation in pharmacokinetics of compounds metabolised via this enzyme. The aim of this study was to understand metabolic clearance of ropinirole in dogs, the enzymes involved in ropinirole metabolism and specially to estimate whether the clearance can be sensitive towards the polymorphism of canine CYP1A2. Metabolism of ropinirole was studied in dog hepatocytes and specific recombinant canine CYP isoforms. Metabolite identification and metabolite formation were evaluated using LC-mass spectrometry. Ropinirole was moderately stable in dog hepatocytes with Clint of 16.3μL/min/million cells, and the metabolites detected were 7-hydroxy ropinirole and respective glucuronide conjugate as well as despropyl ropinirole. Regarding recombinant CYPs either 7-hydroxy ropinirole, despropyl ropinirole or both were detected for each CYP isoform studied. The highest rates of metabolite formation were observed in CYP2B11, CYP2C21, CYP2D15, CYP1A2 and CYP1A1. Fluvoxamine, a fairly selective human CYP1A/CYP2C19 inhibitor inhibited ropinirole metabolism by CYP1A1, CYP1A2, CYP2B11, CYP2C21 and CYP2D15 for 65.8%-100% showing no selectivity towards canine CYP isoforms. Although human metabolism of ropinirole is mainly mediated through CYP1A2, the current study shows that several canine CYP isoforms are able to contribute to the clearance of ropinirole in dogs. This is expected to reduce a possible impact of canine CYP1A2 polymorphism on ropinirole pharmacokinetics.

Pharmacokinetics of maropitant citrate in Rhode Island Red chickens (Gallus gallus domesticus) following subcutaneous administration.

Maropitant citrate is a synthetic neurokinin‐1 receptor antagonist and substance P inhibitor used for control of emesis in dogs in cats. Maropitant citrate is used empirically in birds, despite a lack of pharmacokinetic data in avian species. The objective of this study was to determine the pharmacokinetic profile of a single dose of maropitant citrate 1 and 2 mg/kg subcutaneously (SC) in eight Rhode Island Red hens (Gallus gallus domesticus). A crossover study design was used with 1‐week washout between trials. Blood samples were collected over 36 h after drug administration. Plasma concentrations were measured using liquid chromatography–tandem mass spectrometry and pharmacokinetic parameters were determined via non‐compartmental analysis. The mean maximum plasma concentration, time to maximum concentration, and elimination half‐life following 1 and 2 mg/kg SC were 915.6 ± 312.8 ng/ml and 1195.2 ± 320.2 ng/ml, 0.49 ± 0.21 h and 1.6 ± 2.6 h, and 8.47 ± 2.24 h and 8.58 ± 2.6 h, respectively. Pharmacokinetic data suggests doses of 1 or 2 mg/kg SC may be administered every 12–24 h to maintain above target plasma concentration similar to dogs (90 ng/ml). These data provide a basis for further investigation of maropitant citrate pharmacokinetics and pharmacodynamics in birds.

Using topic modelling for unsupervised annotation of electronic health records to identify an outbreak of disease in UK dogs.

A key goal of disease surveillance is to identify outbreaks of known or novel diseases in a timely manner. Such an outbreak occurred in the UK associated with acute vomiting in dogs between December 2019 and March 2020. We tracked this outbreak using the clinical free text component of anonymised electronic health records (EHRs) collected from a sentinel network of participating veterinary practices. We sourced the free text (narrative) component of each EHR supplemented with one of 10 practitioner-derived main presenting complaints (MPCs), with the 'gastroenteric' MPC identifying cases involved in the disease outbreak. Such clinician-derived annotation systems can suffer from poor compliance requiring retrospective, often manual, coding, thereby limiting real-time usability, especially where an outbreak of a novel disease might not present clinically as a currently recognised syndrome or MPC. Here, we investigate the use of an unsupervised method of EHR annotation using latent Dirichlet allocation topic-modelling to identify topics inherent within the clinical narrative component of EHRs. The model comprised 30 topics which were used to annotate EHRs spanning the natural disease outbreak and investigate whether any given topic might mirror the outbreak time-course. Narratives were annotated using the Gensim Library LdaModel module for the topic best representing the text within them. Counts for narratives labelled with one of the topics significantly matched the disease outbreak based on the practitioner-derived 'gastroenteric' MPC (Spearman correlation 0.978); no other topics showed a similar time course. Using artificially injected outbreaks, it was possible to see other topics that would match other MPCs including respiratory disease. The underlying topics were readily evaluated using simple word-cloud representations and using a freely available package (LDAVis) providing rapid insight into the clinical basis of each topic. This work clearly shows that unsupervised record annotation using topic modelling linked to simple text visualisations can provide an easily interrogable method to identify and characterise outbreaks and other anomalies of known and previously un-characterised diseases based on changes in clinical narratives.

Clinical Applications of Substance P (Neurokinin-1 Receptor) Antagonist in Canine Medicine.

Substance P binds to the Neurokinin-1 (NK-1) receptors found in the emetic center of the central nervous system (CNS) to induce emesis. Maropitant is a selective NK-1 receptor antagonist that inhibits the binding of substance P to NK-1 receptors and is commonly used to prevent and treat vomiting in dogs. This review study aimed to discuss and analyze the therapeutic potential of substance P (Neurokinin-1 receptor) antagonist with a particular focus on the drug maropitant in canine medicine. A systematic literature review was performed to identify the existing literature on the subject during the past 20 years (2001-2021) using such databases as ScienceDirect, PubMed, Scopus, and Google Scholar. The initial search identified 173 articles; however, 41 articles were selected for further analysis, based on the specific inclusion and exclusion criteria. Studies have already confirmed the role of substance P and NK-1 receptors in central pain processing, intestinal smooth muscle contraction, vasodilation, and neurogenic inflammation. Maropitant is one of the most effective veterinary antiemetic drugs that work well against peripheral and central stimuli that trigger the vomiting center. It has been already demonstrated that the therapeutic efficacy of maropitant for managing acute vomiting in dogs is associated with pancreatitis, gastritis, and parvoviral enteritis. It can also prevent and treat chemotherapy-induced emesis and delay the signs of nausea and adverse gastrointestinal effects. Regarding the broad-spectrum antiemetic activity of maropitant, it can be recommended for managing uremic vomiting in dogs. In addition, it has also exhibited an anesthetic sparing effect since the dogs treated with maropitant require a slightly lower percentage of isoflurane as an inhalational anesthetic. The NK-1 receptors are also identified in different areas of the pain pathways. Therefore, NK-1 receptor antagonists might be effective for managing visceral pain. However, further studies are required to establish the broad therapeutic potential of NK-1 receptor antagonist drugs, such as maropitant in canine medicine. It has been shown that the pain associated with the subcutaneous administration of maropitant is due to metacresol, a preservative used in some formulations. Therefore, the side effects can be eliminated by developing novel maropitant formulations specifically for dogs.

Identification of a canine coronavirus in Australian racing Greyhounds.

Coronavirus infection can cause a range of syndromes, which in dogs can include mild-to-severe enteritis that generally resolves rapidly. Fatalities can occur from coinfection with other pathogens, including canine parvovirus. Between late December 2019 and April 2020, canine coronavirus (CCoV) was detected in Australian racing Greyhounds that displayed signs of gastrointestinal disease. The CCoV was genotyped using high-throughput sequencing, recovering 98.3% of a type IIb CCoV, generally thought to cause a mild but highly contagious enteric disease. The Australian CCoV was almost identical (99.9%, whole-genome sequence) to another CCoV associated with an outbreak of severe vomiting in dogs in the United Kingdom at the same time (December 2019-March 2020).

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

To prospectively compare the effectiveness and any adverse effects of apomorphine administered SC or IV for induction of emesis in dogs. 42 client-owned dogs. 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). 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. 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.

Surveillance of a vomiting outbreak in dogs in the UK using owner-derived and internet search data.

In early 2020, the Small Animal Veterinary Surveillance Network reported evidence of an outbreak of acute prolific vomiting in dogs in the UK. The aims of this study were to investigate whether there was evidence for a vomiting outbreak in Dogslife and Google Trends data and to describe its characteristics. Incidence of Dogslife vomiting reports and the Google search index for 'dog vomiting' and 'puppy vomiting' between December 2019 and March 2020 was compared to the respective data from the same months in previous years. Risks for dogs vomiting and factors influencing veterinary attendance in Dogslife were identified using multivariable logistic regression. This study confirmed a vomiting outbreak was evident in UK dogs between December 2019 and March 2020 using data from Dogslife and Google Trends. The odds of a vomiting incident being reported to Dogslife was 1.51 (95% CI: 1.24-1.84) in comparison to previous years. Dogslife data identified differences in owner-decision making when seeking veterinary attention and identified factors associated with dogs at higher odds of experiencing a vomiting episode. Owner-derived data including questionnaires and internet search queries should be considered a valid, valuable source of information for veterinary population health surveillance.

A clinical survey on the electrocardiogram after intravenous granisetron hydrochloride administration in clinically normal dogs

Cardiac side effect of 5-hydroxytryptamine-3 receptor antagonists has been a concern for clinicians. There is a substantial need for greater clarity about the safety of granisetron hydrochloride, an antiemetic agent of this class used in oncological and parvoviral gastroenteritis with acute vomiting in dogs. This study aimed to assess the electrocardiographic effects of a single dose of intravenous granisetron. We randomly assigned 16 adult crossbreed female healthy dogs into two groups of intervention and control and injected them intravenously with granisetron and normal saline, respectively, at a dose of 0.5 ml/kg over one minute. Standard electrocardiography (ECG) was recorded at the baseline, as well as 5, 15, 30, 60, 120, 360, and 720 minutes after the intervention. Heart rate and ECG parameters (PR intervals, QRS duration, ST-segment, T-wave amplitudes, QT, JT, QTc and JTc intervals) were evaluated in lead II.No significant difference was observed between the intervention and the control groups in any of the measured variables at any of the time-points. Mean values of measured parameters showed no significant difference compared with baseline values in the control group, while the granisetron group saw statistically significant but clinically asymptomatic changes in heart rate, PR, QRS, QT, JT, and QTc at different time-points, compared to the baseline values (P&lt;0.05). In conclusion, Granisetron administration was not associated with clinically significant adverse effects on ECG variables or heart rate. Thus, it can be regarded as a relatively safe drug.

Small animal disease surveillance 2020/21: SARS-CoV-2, syndromic surveillance and an outbreak of acute vomiting in UK dogs.

Small animal disease surveillance 2020/21: SARS-CoV-2, syndromic surveillance and an outbreak of acute vomiting in UK dogs.

Outbreak of Severe Vomiting in Dogs Associated with a Canine Enteric Coronavirus, United Kingdom.

The lack of population health surveillance for companion animal populations leaves them vulnerable to the effects of novel diseases without means of early detection. We present evidence on the effectiveness of a system that enabled early detection and rapid response a canine gastroenteritis outbreak in the United Kingdom. In January 2020, prolific vomiting among dogs was sporadically reported in the United Kingdom. Electronic health records from a nationwide sentinel network of veterinary practices confirmed a significant increase in dogs with signs of gastroenteric disease. Male dogs and dogs living with other vomiting dogs were more likely to be affected. Diet and vaccination status were not associated with the disease; however, a canine enteric coronavirus was significantly associated with illness. The system we describe potentially fills a gap in surveillance in neglected populations and could provide a blueprint for other countries.

Retrospective evaluation of the induction of emesis with apomorphine as treatment for gastric foreign bodies in dogs (2010-2014): 61 cases.

To determine the success rate and complications associated with inducing emesis in dogs that have ingested foreign material. Retrospective case series, 2010-2014. Private practice and referral center. Sixty-one client-owned dogs that had emesis induced for the treatment of ingestion of foreign material. None. Emesis was successfully induced in 59 of 61 (97%) dogs administered an emetic. Of those 59 dogs, 46 (78%) produced the foreign body. There were no complications reported in any of the dogs in which emesis was successfully induced. Dogs in which emesis was successfully induced were likely to produce the foreign body (P=0.01). Based on the results of this study, emesis appears to be a safe and effective means for the removal of certain gastric foreign bodies in dogs.

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...

Pharmacokinetics of single doses of maropitant citrate in adult horses.

The neurokinin-1 (NK) receptor antagonist, maropitant citrate, mitigates nausea and vomiting in dogs and cats. Nausea is poorly understood and likely under-recognized in horses. Use of NK-1 receptor antagonists in horses has not been reported. The purpose of this study was to determine the pharmacokinetic profile of maropitant in seven adult horses after single intravenous (IV; 1mg/kg) and intragastric (IG; 2mg/kg) doses. A randomized, crossover design was performed. Serial blood samples were collected after dosing; maropitant concentrations were measured using LC-MS/MS. Pharmacokinetic parameters were determined using noncompartmental analysis. The mean plasma maropitant concentration 3min after IV administration was 800±140ng/ml, elimination half-life was 10.37±2.07h, and volume of distribution was 6.54±1.84L/kg. The maximum concentration following IG administration was 80±40ng/ml, and elimination half-life was 9.64±1.27hr. Oral bioavailability was variable at 13.3±5.3%. Maropitant concentrations achieved after IG administration were comparable to those in small animals. Concentrations after IV administration were lower than in dogs and cats. Elimination half-life was longer than in dogs and shorter than in cats. This study is the basis for further investigations into using maropitant in horses.

Efecto de la premedicación de Fentanilo-acepromacina y Fentanilo-xilacina sobre la presentación de vómito posoperatorio en perros

La inclusión de opioides durante la preanestesia y anestesia, potencialmente puede incrementar la presentación de vómito y náuseas posoperatorias, acrecentando el riesgo de presentación de sangrado, dehiscencias, neumonía poraspiración o esofagitis. En éste estudio se evaluó la presentación de vómito,salivación excesiva y anorexia durante 24 horas del periodo posanestésico en 100 perros ASA I y II. El grupo A (n: 40) fue premedicado con una mezcla de acepromacina a 0.08 mg/kg i.v. y fentanilo a 5 μg/kg i.v. y el grupo X (n: 60) con xilacina a 0.3 mg/kg i.v. más fentanilo a 5 μg/kg i.v. La inducción anestésica para ambos grupos se realizó con propofol a 4 mg/kg y el mantenimiento con isoflurano a 1,5-3%. La presentación general de vómito post-anestesia fue del 12%. Entre ambos grupos no se encontraron diferencias significativas en la incidencia de vómito a las 2 (p= 0,837), a las 6 (p= 0,439) y a las 24 horas (p= 0,639). No hubo diferencias significativas entre grupos para la presentación de salivación excesiva o anorexia. Se encontró una asociación entre vómito post-anestésico y cirugía del aparato reproductivo en hembras (p= 0,02). Se concluye que un único bolo de fentanilo a 5 μg/kg con acepromacina a 0,08 mg/kg o xilacina 0,3 mg/kg durante la premedicación anestésica, no incrementa la presentación de vómito en las primeras 24 horas del postquirúrgico en perros.

Effects of Three Acepromazine Doses on the Incidence of Morphine-Induced Vomiting, Sedation and Some Physiological Variables in Dogs

Background: Acepromazine was found to reduce the incidence of vomiting induced by opioids such as morphine, hydromorphone and oxymorphone in dogs. Despite the effectiveness of the phenothiazine in preventing opioid-induced vomiting in this species, a single dose of acepromazine (0.05 mg/kg) was tested and the influence of dose on the antiemetic effect of the drug is unknown. The primary objective of this study was to evaluate the effect of three acepromazine doses on the incidence of vomiting induced by morphine in dogs. A secondary aim was to assess the degree of sedation and effects on physiological variables following administration of the combinations tested.Materials, Methods &amp; Results: All dogs received 0.5 mg/kg morphine (IM). Fifteen min before morphine, dogs in the Control, ACPLD, ACPMD and ACPHD groups were administered (IM) physiological saline or acepromazine at doses of 0.025, 0.05 and 0.1 mg/kg, respectively. In Phase 1, purpose-bred dogs (n = 8) underwent each of the four treatments in a randomized, crossover design; the incidence of vomiting, sedation, pulse rate (PR), systolic, mean and diastolic blood pressures (SAP, MAP and DAP) were investigated for 60 min. Sedation was assessed by a numeric descriptive scale (NDS, range 0-3) and a simple numerical scale (SNS, range 1-10). In Phase 2, client-owned dogs (n = 50) received a single treatment and only the incidence of vomiting was assessed. There was no significant difference between groups on the incidence of vomiting recorded in Phase 1, Phase 2 and the average of Phases 1 and 2. A significant decrease in PR was observed in most groups but no significant difference was detected between groups. Blood pressure decreased in all groups; during most of the evaluation period, SAP, MAP and DAP were significantly higher in the Control than in other treatments. Dogs in this study presented mild to intense sedation. A significant difference in NDS scores was observed between the Control and ACPMD groups whereas for SNS scores, significant differences were detected between the ACPMD and ACPHD groups compared with the Control group. The number of dogs presenting intense sedation as judged by the NDS (NDS score = 3) were: 1/8, 3/8, 3/8 and 4/8 dogs in the Control, ACPLD, ACPMD and ACPHD groups, respectively.Discussion: The hypothesis of the study was rejected. The acepromazine dose did not influence the frequency of morphineinduced vomiting, the degree of sedation or cardiovascular variables after administration of either treatment. The frequency of vomiting was high (≥ 75%) in dogs of the present study regardless of the treatment administered. There was no significant difference in the frequency of vomiting in ACPLD, ACPMD and ACPHD as compared to the Control group. This finding was unexpected because it has been reported in a previous study that acepromazine reduced the incidence of opioid-induced vomiting in dogs. ACPLD, ACPMD and ACPHD improved the quality of sedation compared to the Control treatment but no significant difference in sedation scores was observed among these groups. These findings suggest that, when combined to morphine, there is no improvement in sedation when the acepromazine dose is increased above 0.025 mg/kg in dogs. Despite a significant decrease, mean values of PR, SAP, MAP and DAP remained within the physiological range for conscious dogs. In summary, none of the acepromazine doses was effective in preventing morphine-induced vomiting in dogs. Sedation is greater after acepromazine-morphine combinations than after morphine alone and is not influenced by the acepromazine dose. Cardiovascular effects induced by combinations administered in this study were well tolerated and of little clinical relevance to healthy conscious dogs.