Sedative effects of three doses of romifidine in comparison with medetomidine in cats

ObjectiveTo compare the sedative effects of three doses of romifidine with one dose of medetomidine.Study designProspective blinded experimental cross-over.AnimalsFive adult Domestic Short Hair cats.MethodsCats were administered romifidine at 80, 120 and 160 μg kg^?1 or medetomidine at 20 μg kg^?1 (M20) intramuscularly (IM). Sedative effects were assessed for 3 hours by summing the scores given to posture, auditory response, resistance to positioning, muscular relaxation, and response to noxious stimuli, giving a total sedation score (TS). The area under the curve (AUC) of TS ≥7 (the score considered as clinically useful sedation) was calculated. Times to stages of sedation were determined. Some physiological parameters were measured. Data to compare treatments were analysed by anova or Kruskal–Wallis test as relevant.ResultsAll treatments gave a TS considered clinically useful. There were no significant differences between treatments for times to onset of sedation, maximum TS reached, or AUC. Differences between romifidine treatments for other sedation parameters were not significant but the time to maximum TS and to recovery was shortest in M20. Heart rate (HR) fell significantly with all treatments and, although with M20 it recovered at 65 minutes, it remained significantly depressed for 3 hours after all romifidine treatments. Most cats vomited, and/or hypersalivated after all treatments.ConclusionsDoses of 80, 120 and 160 μg kg^?1 romifidine IM produce sedation in cats which is similar to that following medetomidine 20 μg kg^?1. Recovery from sedation and of physiological parameters was quickest after M20.Clinical relevanceDoses of romifidine considerably lower than those investigated by previous authors give a clinically useful level of sedation, and their use might result in less side effects and a quicker recovery.     

Sedative and antinociceptive effects of dexmedetomidine and buprenorphine after oral transmucosal or intramuscular administration in cats

ObjectiveTo compare sedation and antinociception after oral transmucosal (OTM) and intramuscular (IM) administration of a dexmedetomidine-buprenorphine combination in healthy adult cats.Study designRandomized, ‘blinded’ crossover study, with 1 month washout between treatments.AnimalsSix healthy neutered female cats, weighing 5.3–7.5 kg.MethodsA combination of dexmedetomidine (40 μg kg^?1) and buprenorphine (20 μg kg^?1) was administered by either the OTM (buccal cavity) or IM (quadriceps muscle) route. Sedation was measured using a numerical rating scale, at baseline and at various time points until 6 hours after treatment. At the same time points, analgesia was scored using a dynamic and interactive visual analogue scale, based on the response to an ear pinch, and by the cat’s response to a mechanical stimulus exerted by a pressure rate onset device. Physiological and adverse effects were recorded, and oral pH measured. Signed rank tests were performed, with significance set at p < 0.05. Data are presented as median and range.ResultsThere were no differences in sedation or antinociception scores between OTM and IM dosing at any of the time points. Nociceptive thresholds increased after both treatments but without significant difference between groups. Buccal pH remained between 8 and 8.5. Salivation was noted after OTM administration (n = 2) and vomiting after both OTM (n = 4), and IM (n = 3) dosing.Conclusions and clinical relevanceIn healthy adult cats, OTM administration of dexmedetomidine and buprenorphine resulted in comparable levels of sedation and antinociception to IM dosing. The OTM administration may offer an alternative route to administer this sedative-analgesic combination in cats.     

Effect of single and multiple doses of 0.2% brimonidine tartrate in the glaucomatous Beagle

The objective of this study was to evaluate the changes in intraocular pressure (IOP) in glaucomatous dogs after instillations of 0.2% brimonidine once, twice and three times daily in single day studies, and after twice and three times daily for 4 days in multiple dose studies. We studied eight Beagles with inherited primary open angle glaucoma. Applanation tonometry (IOP), pupil size (PS) and heart rate (HR) measurements were obtained at 8 am, 10 am, 1 pm, 3 pm and 5 pm. The studies were divided into: eight glaucoma dogs and five of the eight dogs that demonstrated greater response to 0.2% brimonidine. Single-dose drug studies are divided into placebo (0.5% methylcellulose), 0.2% brimonidine administered once daily (8 am); twice daily (8 am and noon); and three times daily (8 am, noon and 5 pm). The 5-day multiple-dose studies included: day 1, no drug; and 4 days, 0.2% brimonidine instillations either twice daily (8 am and 2 pm) or three times daily (8 am, 2 pm and 9 pm). Statistical comparisons between drug groups included control (nondrug) and treated (placebo/0.2% brimonidine) eyes for both single- and multiple-dose studies. The mean +/- SEM diurnal decrease in IOP in the eight glaucomatous Beagles for the control and placebo eyes were 3.4 +/- 4.7 and 5.4 +/- 2.8 mmHg, respectively. The mean +/- SEM diurnal decrease in IOP after 0.2% brimonidine once, twice and three times daily was 6.4 +/- 3.5, 8.0 +/- 6.1 and 9.8 +/- 8.1 mmHg, respectively; this trend was not significant statistically. Significant miosis occurred starting 2 h postinstillations, and the resultant mean +/- SD pupil size was 2.7 +/- 0.3 mm. A significant decrease in heart rate also occurred (12%). In the five most responsive dogs the changes in PS and HR during these studies were similar to the larger group, but significant decreases in IOP occurred at most measurement times. In the multiple-dose study with 0.2% brimonidine twice daily the mean +/- SEM decrease in IOP for day 1 to day 4 was 5.0 +/- 1.3, 5.7 +/- 1.3, 1.4 +/- 3.3 and 4.9 +/- 1.3 mmHg, respectively. When 0.2% brimonidine was instilled three times daily the mean +/- SEM diurnal IOP decrease was from day 1 to day 4 and was 0.75 +/- 1.3, 2.4 +/- 1.5, 1.2 +/- 2.7 and 1.4 +/- 1.8 mmHg, respectively. The mean change in pupil diameter was 1.3 +/- 0.5 mm. Decrease in HR averaged 22%. In the same single-dose studies with the five most responsive dogs, PS and HR were similar, but the decreases in IOP were significant at more measurement intervals. We conclude that 0.2% brimonidine produces a decrease in IOP in dogs, a statistically significant miosis, and a reduced heart rate (12-22%). However, because of the limited drug-induced ocular hypotension, brimonidine should be combined with other drugs when used for the glaucomas in the dog.     

Sedative, analgesic and cardiorespiratory effects of romifidine in cats

OBJECTIVE: To evaluate the sedative, analgesic, and cardiorespiratory effects of intramascular (IM) romifidine in cats. STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: Ten healthy adult cats. METHODS: Romifidine (100, 200, and 400 microg kg(-1)) or xylazine (1 mg kg(-1)) was given IM in a cross-over study design. Heart rate (HR), respiratory rate (RR), rectal temperature (RT), hemoglobin saturation, oscillometric arterial pressure, and scores for sedation, muscle relaxation, position, auditory response, and analgesia were determined before and after drug administration. Time to recumbency, duration of recumbency, and time to recover from sedation were determined. Subjective evaluation and cardiorespiratory variables were recorded before and at regular intervals for 60 minutes after drug administration. RESULTS: Bradycardia developed in all cats that were given romifidine or xylazine. No other significant differences in physiologic parameters were observed from baseline values or between treatments. Increasing the dose of romifidine did not result in increased sedation or muscle relaxation. Cats given xylazine showed higher sedation and muscle relaxation scores over time. Analgesia scores were significantly higher after administration of romifidine (400 microg kg(-1)) and xylazine (1 mg kg(-1)) than after romifidine at 100 or 200 microg kg(-1). Duration of lateral recumbency was not significantly different between treatments; however, cats took longer to recover after administration of 400 micro g kg(-1) romifidine. CONCLUSIONS AND CLINICAL RELEVANCE: Bradycardia is the most important adverse effect after IM administration of romifidine at doses ranging from 100 to 400 microg kg(-1) or 1 mg kg(-1) of xylazine in cats. The sedative effects of romifidine at 200 microg kg(-1) are comparable to those of 1 mg kg(-1) of xylazine, although muscle relaxation and analgesia were significantly less with romifidine than with xylazine.     

Sedative and analgesic effects of buprenorphine,combined with either acepromazine or dexmedetomidine,for premedication prior to elective surgery in cats and dogs

ObjectiveTo evaluate the sedative and analgesic effects of intramuscular buprenorphine with either dexmedetomidine or acepromazine, administered as premedication to cats and dogs undergoing elective surgery.Study designProspective, randomized, blinded clinical study.AnimalsForty dogs and 48 cats.MethodsAnimals were assigned to one of four groups, according to anaesthetic premedication and induction agent: buprenorphine 20 μg kg^?1 with either dexmedetomidine (dex) 250 μg m^?2 or acepromazine (acp) 0.03 mg kg^?1, followed by alfaxalone (ALF) or propofol (PRO). Meloxicam was administered preoperatively to all animals and anaesthesia was always maintained using isoflurane. Physiological measures and assessments of pain, sedation and mechanical nociceptive threshold (MNT) were made before and after premedication, intraoperatively, and for up to 24 hours after premedication. Data were analyzed with one-way, two-way and mixed between-within subjects anova, Kruskall–Wallis analyses and Chi squared tests. Results were deemed significant if p ≤ 0.05, except where multiple comparisons were performed (p ≤ 0.005).ResultsCats premedicated with dex were more sedated than cats premedicated with acp (p < 0.001) and ALF doses were lower in dex cats (1.2 ± 1.0 mg kg^?1) than acp cats (2.5 ± 1.9 mg kg^?1) (p = 0.041). There were no differences in sedation in dogs however PRO doses were lower in dex dogs (1.5 ± 0.8 mg kg^?1) compared to acp dogs (3.3 ± 1.1 mg kg^?1) (p < 0.001). There were no differences between groups with respect to pain scores or MNT for cats or dogs.ConclusionChoice of dex or acp, when given with buprenorphine, caused minor, clinically detectable, differences in various characteristics of anaesthesia, but not in the level of analgesia.Clinical relevanceA combination of buprenorphine with either acp or dex, followed by either PRO or ALF, and then isoflurane, accompanied by an NSAID, was suitable for anaesthesia in dogs and cats undergoing elective surgery. Choice of sedative agent may influence dose of anaesthetic induction agent.     

Sedative effects of propofol in horses

Objective  We hypothesized that propofol can produce rapidly-reversible, dose-dependent standing sedation in horses.
Study design  Prospective randomized, blinded, experimental trial.
Animals  Twelve healthy horses aged 12 ± 6 years (mean ± SD), weighing 565 ± 20 kg, and with an equal distribution of mares and geldings.
Methods  Propofol was administered as an intravenous bolus at one of three randomized doses (0.20, 0.35 and 0.50 mg kg⁻¹). Cardiovascular and behavioral measurements were made by a single investigator, who was blinded to treatment dose, at 3 minute intervals until subjective behavior scores returned to pre-sedation baseline values. Continuous data were analyzed over time using repeated-measures anova and noncontinuous data were analyzed using Friedman tests.
Results  There were no significant propofol dose or temporal effects on heart rate, respiratory rate, vertical head height, or jugular venous blood gases (pH_v, P_vO₂, P_vCO₂). The 0.35 mg kg⁻¹ dose caused mild sedation lasting up to 6 minutes. The 0.50 mg kg⁻¹ dose increased sedation depth and duration, but with increased ataxia and apparent muscle weakness.
Conclusions and clinical relevance  Intravenous 0.35 mg kg⁻¹ propofol provided brief, mild sedation in horses. Caution is warranted at higher doses due to increased risk of ataxia.     

Sedative and physiologic effects of low-dose intramuscular alfaxalone in dogs

Objective

To describe the sedative and physiologic effects of two doses of alfaxalone administered intramuscularly in dogs.

Sedative effects of two doses of alfaxalone in combination with methadone and a low dose of dexmedetomidine in healthy Beagles

ObjectiveTo evaluate the sedative effects of two doses of alfaxalone when added to a combination of dexmedetomidine and methadone injected intramuscularly (IM) in healthy Beagles.Study designRandomized, blinded, crossover, experimental study.AnimalsA group of six adult Beagles.MethodsDogs were sedated on three different occasions with IM dexmedetomidine (3 μg kg^–1) and methadone (0.3 mg kg^–1) combined with two doses of alfaxalone (0.5 and 1 mg kg^–1; A0.5 and A1, respectively) or saline (A0). Quality of sedation, response to tail clamping and rectal temperature were recorded at baseline, 5, 15, 25, 35 and 45 minutes. Pulse and respiratory rates, oxygen saturation of haemoglobin (SpO₂) and noninvasive blood pressure (NIBP) were recorded every 5 minutes. Onset of sedation and duration of recumbency, response to venous catheterization and recovery quality were assessed. Physiological variables (analysis of variance) were analysed between treatments and within treatments compared with baseline (Student t test). Nonparametric data were analysed using Friedman and Cochran’s Q tests. Significance was p < 0.05.ResultsSedation scores were significantly higher when alfaxalone was co-administered (area under the curve; p = 0.024, A0.5; p = 0.019, A1), with no differences between doses. Onset of sedation was similar, but duration of recumbency was longer in A0.5 than in A0 [median (minimum–maximum), 43 (35–54) versus 30 (20–47) minutes, p = 0.018], but not in A1. Response to venous catheterization and tail clamping, and quality of recovery (acceptable) presented no differences between treatments. A decrease in all physiological variables (compared with baseline) was observed, except for NIBP, with no differences between treatments. All dogs required oxygen supplementation due to reduced SpO₂.Conclusions and clinical relevanceAdding alfaxalone to methadone and dexmedetomidine enhanced sedation and duration of recumbency. Although cardiopulmonary depression was limited, oxygen supplementation is advisable.     

Comparison of intranasal and intramuscular ketamine‐midazolam combination in cats

ObjectiveThe aim of the present study was to compare intranasal (INS) and intramuscular (IM) routes of administration of a ketamine-midazolam combination in cats.Study designRandomized block design.AnimalsTwelve healthy mixed breed cats (six males and six females).MethodsThe drug combination was ketamine (14 mg kg⁻¹) and midazolam (0.5 mg kg⁻¹). In the IM group, drugs were injected into quadratus femoris muscle; in the INS. group, the combination dropped equally into the two nostrils. Pulse and respiratory rates, peripheral haemoglobin oxygen saturation (SpO₂) and rectal temperature were monitored before and at intervals after drug administration. Time to onset and duration of sedation and, during recovery to head up, sternal recumbency and recovery were recorded.ResultsThere were no significant differences between the groups in any time measured except for recovery to sternal recumbency, where time was lower in the INS than in the IM (p = 0.034). Respiratory rate was greater in the INS than in the IM group (p = 0.029), but there was no difference between groups in other physiological parameters. In both groups SpO₂ was low before and fell further during sedation.ConclusionsThe results substantiated that INS ketamine-midazolam can produce effective sedation in cats.Clinical relevanceIntranasal (INS) administration of ketamine-midazolam is atraumatic, and its use may avoid the pain of injection of ketamine combinations when this drug is used to induce sedation in cats.     

Sedative and analgesic effects of two subanaesthetic doses of ketamine in combination with methadone and a low dose of dexmedetomidine in healthy dogs

ObjectiveTo evaluate the sedative, analgesic and recovery characteristics of two subanaesthetic ketamine doses in combination with dexmedetomidine and methadone for intramuscular sedation in healthy Beagles.Study designRandomized, blinded, crossover, experimental study.AnimalsSix healthy adult Beagles.MethodsDogs were randomly given three treatments: dexmedetomidine (3 μg kg^–1) and methadone (0.3 mg kg^–1) combined with ketamine at 1 and 2 mg kg^–1 (K1 and K2, respectively) or saline (K0), intramuscularly. Sedation score, response to tail clamping and rectal temperature were recorded at baseline, 5, 15, 25, 35, and 45 minutes posttreatment. Pulse rate (PR), respiratory rate, oxygen haemoglobin saturation and noninvasive blood pressure were also recorded at baseline and every 5 minutes until 45 minutes posttreatment. Onset and duration of recumbency, response to venous catheterization and recovery quality were also assessed. Sedation and physiological variables were compared between treatments and within treatments compared to baseline (analysis of variance). Nonparametric data were analysed with the Friedman and Cochran’s Q tests; p < 0.050.ResultsIncreased sedation was found at 15 (K0 and K1), 25 (all treatments) and 35 (K1) minutes compared with baseline. Sedation score, onset (3–12 minutes) and duration of recumbency (29–51 minutes) were similar between treatments. Recovery quality was considered acceptable in all cases. Response to tail clamping was inconsistent within treatments with no differences between them. None of the dogs responded to venous catheterization. There were no differences between treatments in physiological variables, except for PR which was higher in K2 than in K0. Oxygen supplementation was required in five and three dogs administered saline and ketamine, respectively.Conclusions and clinical relevanceThe addition of 1 or 2 mg kg^–1 of ketamine to methadone and dexmedetomidine combination did not enhance sedation or antinociception in healthy dogs. Recovery quality was unaffected.     

Sedative and analgesic effects of romifidine in camels (Camelus dromedarius)

ObjectiveTo evaluate the clinical effectiveness and the sedative and analgesic effects of intravenous (IV) romifidine in camels.Study designRandomized prospective study.AnimalsEighteen healthy adult Dromedary camels.MethodsRomifidine was administered IV to camels (n = 6) at three different doses (40, 80 or 120 μg kg^?1). Time of onset, degree and duration of sedation and analgesia were recorded immediately after drug administration. Heart rate, respiratory rate, ruminal contractions, muscle relaxation, response to auditory and tactile stimulation, distance between ears, distance from lower lip to the ground, and degree of ataxia were also recorded pre-administration and at 5, 15, 30, 45, 60, 90, 120 and 180 minutes post-administration. Plasma glucose, blood urea nitrogen and creatinine were measured.ResultsRomifidine produced dose dependent sedation and analgesia. Significant decreases in heart rate (p < 0.001), ruminal contractions (p < 0.05), distance from lower lip to the ground (p < 0.001), response to auditory and tactile stimuli (p < 0.01), and significant increases in the degree of ataxia (p < 0.01), distance between the ear tips (p < 0.001) and blood glucose (p < 0.01) concentration were recorded after administration of romifidine until recovery. However, no significant changes in rectal temperature and respiratory rate were recorded.Conclusions and clinical relevanceIntravenous administration of romifidine at three different doses appeared to be an effective sedative and analgesic agent for camels. Bradycardia, ruminal atony, and hyperglycemia were the most important adverse effects after IV administration of romifidine. The IV administration of romifidine at a dose rate of 120 μg kg^?1 caused profound sedation and analgesia. Romifidine could be used for chemical restraint for a variety of diagnostic and minor surgical procedures in camels.     

Ultrasonographic characterization of the feline cardia and pylorus in 34 healthy cats and three abnormal cats

A prospective study was performed in 34 fasted healthy cats to describe the normal ultrasonographic anatomy of the cardia and pylorus. Measurements were obtained for the caudal esophageal wall thickness (Ew), cardia wall thickness (Cw), pyloric wall thickness (Pw), thickness of the pyloric muscularis (Mp), length of the thicker part of the proximal duodenal submucosa (Dl). Among the 34 cats, 24 were examined using a linear transducer, and 10 with a microconvex transducer. Ew and Cw could be measured in 70% of the cats when a linear transducer was used, in 100% of the cats when a microconvex probe was used, Pw and Mp could be measured in 100% of the cats whatever probe was used. The submucosa of the most proximal part of the duodenum was thicker in half of the cats in longitudinal section. The muscularis layer of the pylorus was triangular in longitudinal section and thicker than the muscularis of the proximal duodenum. The mean for Ew, Cw, Pw, Mp, and DI was 4.9 mm (SD = 1.1), 5 mm (SD = 0.6), 4.4 mm (SD = 0.6), 2.5 mm (SD = 0.5), and 4.7 mm (SD = 2.38), respectively. Three cats with abnormalities of the cardia and pylorus are also described to illustrate clinical implications.     

Preliminary investigations into the analgesic effects of topical ocular 1% morphine solution in dogs and cats

ObjectiveTo perform preliminary evaluations into the ocular analgesic effect of topical 1% morphine in a clinical setting and to determine onset, duration and complications.Study designProspective, randomised, blinded clinical study.AnimalsTwenty six dogs and seventeen cats, all client‐owned.MethodsDogs and cats with corneal ulceration requiring medical treatment or corneal conditions requiring surgery were included and randomly assigned to receive one drop of topical morphine (group M) or base solution (group B). Recordings were made prior to application and at 5, 10, 20, 30, 40, 50 and 60 minutes, then 2, 3, 4, 5 and 6 hours. Corneal aesthesiometry, blink rates and scores for blepharospasm (BLEPH), conjunctival hyperaemia (CH) and lacrimation (LAC) were recorded. Statistical analyses used anova,t‐tests and Mann–Whitney U tests as relevant.ResultsNo significant effect of treatment group on any recordings was found at any time point in either dogs or cats. Adverse effects of increased BLEPH, CH or blink rate were observed in six animals (three cats from group M and three dogs from group B), occurring within 5 minutes of drop application and lasting for between 10 minutes and 6 hours.Conclusions and clinical relevanceTopical ocular morphine showed no measurable analgesic effect against corneal pain in dogs and cats.     

Sedative and analgesic effects of intravenous xylazine and tramadol on horses

This study was performed to evaluate the sedative and analgesic effects of xylazine (X) and tramadol (T) intravenously (IV) administered to horses. Six thoroughbred saddle horses each received X (1.0 mg/kg), T (2.0 mg/kg), and a combination of XT (1.0 and 2.0 mg/kg, respectively) IV. Heart rate (HR), respiratory rate (RR), rectal temperature (RT), indirect arterial pressure (IAP), capillary refill time (CRT), sedation, and analgesia (using electrical stimulation and pinprick) were measured before and after drug administration. HR and RR significantly decreased from basal values with X and XT treatments, and significantly increased with T treatment (p < 0.05). RT and IAP also significantly increased with T treatment (p < 0.05). CRT did not change significantly with any treatments. The onset of sedation and analgesia were approximately 5 min after both X and XT treatments; however, the XT combination produced a longer duration of sedation and analgesia than X alone. Two horses in the XT treatment group displayed excited transient behavior within 5 min of drug administration. The results suggest that the XT combination is useful for sedation and analgesia in horses. However, careful monitoring for excited behavior shortly after administration is recommended.     

Evaluation of the clinical efficacy and safety of dexmedetomidine or medetomidine in cats and their reversal with atipamezole

OBJECTIVE: To evaluate and compare the clinical effects of dexmedetomidine (DEX) and medetomidine (MED) in cats, and their reversal with atipamezole (ATI). Study design Prospective blinded randomized multi-centre clinical trial. Animals One hundred and twenty client-owned cats. METHODS: Cats were randomly allocated to receive a single intramuscular (IM) injection of either DEX (0.04 mg kg(-1), n = 62) or MED (0.08 mg kg(-1), n = 58) for minor procedures requiring sedation and analgesia. Afterwards, ATI (0.2 mg kg(-1)) was administered IM to half the cats, randomly assigned. Prior to, during and after the procedure the sedative, analgesic and cardiorespiratory effects and body temperature were assessed. RESULTS: Dexmedetomidine and MED produced clinically and statistically comparable effects. The intended procedure(s) could be performed in over 90% of cats. Sedation and analgesia were apparent within 5 minutes, peak effects were observed at approximately 30 minutes and spontaneous recovery occurred by 180 minutes of injection. Heart and respiratory rate and body temperature decreased significantly over time and had not returned to baseline values 180 minutes after administration. ATI administration completely reversed the sedative and analgesic effects, returned the heart rate to normal and prevented any further reductions in respiratory rate and body temperature in both DEX- and MED-treated cats. The reporting of adverse events was low and the most commonly observed event was vomiting (7%). No serious adverse events or concerns regarding safety were reported. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine (0.04 mg kg(-1)) produced comparable sedative and analgesic effects to MED (0.08 mg kg(-1)) in cats. DEX produced adequate sedation and analgesia for radiography, grooming, dental care and lancing of abscesses. ATI fully reversed the clinical effects of DEX.     

Sedative effects of intramuscular alfaxalone in pet guinea pigs (Cavia porcellus)

Objective

To evaluate the efficacy and side effects of alfaxalone administered intramuscularly (IM) as a sedative agent in guinea pigs undergoing survey radiographs.