Use of mirtazapine in the treatment of canine behaviour problems: A review of 32 cases

BACKGROUND

Canine behaviour problems seen by speciality behavioural medicine services often involve chronic anxiety disorders that have resulted in maladaptation of the individual to its environment. Common stressors include the presence of other individuals (other dogs or people), noise and being alone. The treatment of these behavioural problems usually includes a combination of behaviour modification, environmental modification and biological therapies. Within the latter, anxiolytic drugs such as clomipramine or fluoxetine have proven useful.

METHODS

Here, we present a retrospectively analysed series of 32 cases that were treated with the anxiolytic drug mirtazapine, which is widely used in human medicine but has not previously been reported for the treatment of behavioural problems in dogs (although it is marketed as an appetite stimulant in cats). Cases included dogs with a range of anxiety-related behavioural problems.

RESULTS

Eighty-one percent of dogs that presented with a behavioural problem showed improvement and suspected adverse effects were mild and tolerable.

LIMITATIONS

Further studies are required to isolate this result from the other therapeutic measures and to compare its efficacy with other drugs.

CONCLUSION

Mirtazapine appears to be a suitable and safe option for the treatment of anxiety-related behavioural problems in dogs.

The Influence of Noise Level on the Stress Response of Hospitalized Cats

The study aimed to investigate the impact of noise levels in the hospital environment on the stress experienced by hospitalized cats undergoing elective ovariohysterectomy surgery. A total of 33 domestic female cats were included in the study, divided into four groups: a control group (CG) and three experimental groups based on ward noise levels: G1 (Quiet, <60 dB), G2 (Medium, between 60 and 85 dB), and G3 (Noisy, >85 dB). Behavioral assessments, respiratory rate (RR), and plasma cortisol levels ([Cort]p) were measured as indicators of stress. A composite measure of stress, termed the final stress value (FSV), was calculated by summing scores across various behavioral categories. Data collection occurred at three time points: immediately following surgery (T1), and at 2 h (T2) and 3 h (T3) post-surgery. FSV and RR were assessed at all three time points (T1, T2, and T3), while [Cort]p levels were measured at T1 and T3. The study observed that the median values of FSV, RR, and [Cort]p tended to increase with both higher noise levels and longer exposure durations to noise. Significant differences in RR were found between group pairs G1G2 at T1 (|D| = 0.63 < cut-off = 0.98), and G2G3 at T2 (|D| = 0.69 < cut-off = 0.97). Regarding [Cort]p, significant differences were noted between the CGG1 group pair at T0 (p < 0.01), and T3 (p = 0.03). Furthermore, an excellent Spearman correlation coefficient (rho = 0.91) was found between FSV and RR, indicating that RR can serve as an effective tool for assessing stress levels in cats. The findings of this study provide valuable insights into the welfare of cats in a hospital environment and support the scientific validity of existing recommendations aimed at improving their well-being. Specifically, the study underscores the importance of minimizing noise levels in hospitals as a means to reduce stress in cats. This conclusion aligns with existing guidelines and recommendations for enhancing the welfare of hospitalized cats.

Influence of a single oral dose of trazodone on intradermal histamine reactivity in clinically healthy dogs

BACKGROUND

Drug interactions are significant considerations for intradermal testing (IDT). Trazodone (TRZ) is an anxiolytic and selective histaminergic (H1 ) antagonist with no interaction in human prick tests; however, interaction in canine IDT is unknown.

HYPOTHESIS/OBJECTIVES

Trazodone will not adversely affect intradermal histamine reactions in dogs.

ANIMALS

Fourteen nonanxious, nonatopic, healthy client-owned dogs were enrolled in this randomised, blinded, cross-over study.

MATERIALS AND METHODS

Dogs were randomised to receive low-dose TRZ (4 mg/kg) (Teva Pharmaceuticals), high-dose TRZ (8 mg/kg) or no TRZ per os two hours before intravenous sedation with dexmedetomidine (5 mcg/kg) (Dexdomitor; Zoetis). Intradermal testing was performed with five quadrupling dilutions of histamine (1:100,000 to 1:25,600,000 w/v; Greer) and 0.9% saline (Hospira), observing a minimum two weeks washout period between treatments. Two observers, who were blinded to treatment and the identity of the injections, evaluated each test using previously established subjective and objective methods.

RESULTS

The mean wheal diameter of histamine 1:1,600,000 w/v was significantly smaller with low-dose TRZ (4 mg/kg) compared to the control group (p = 0.048; repeated measures ANOVA with post hoc Tukey's test). For all other histamine dilutions and saline, mean wheal diameter was not significantly different among groups. There were no significant differences in the subjective scores of all histamine dilutions and saline (p > 0.05; Friedman test).

CONCLUSION AND CLINICAL RELEVANCE

A single oral dose of TRZ does not adversely affect intradermal histamine reactions in dogs.

Daily dosing of cannabidiol (CBD) demonstrates a positive effect on measures of stress in dogs during repeated exposure to car travel

Dogs are routinely exposed to events that may elicit stress and result in negative emotional states which can impact pet dog welfare. One event many dogs living with people are routinely exposed to is car travel, with many dogs displaying behaviors, along with corresponding physiological responses, that are indicative of stress and anxiety. There are a range of management and treatment options that exist from behavior modification, drug therapy, and supplements, often with varying results. The aim of this study was to evaluate whether multiple doses of a tetrahydrocannabinol-free cannabidiol (CBD) distillate over a period of 6 mo could positively influence measures of stress in dogs. In a blinded, parallel design study, dogs (n = 19) underwent a series of short car journeys (test) where a range of physiological and behavioral measures were collected pre, during, and post-test. The car journeys elicited stress in this population of dogs, as indicated by significant changes (P < 0.05) in several stress-related measures (serum cortisol, heart rate, heart rate variability, whining, lip licking, yawning, and qualitative behavioral ratings) observed from baseline to test, which persisted over repeated car travel events. The mitigating effect of CBD treatment varied by measure, with cortisol, whining, lip licking, and qualitative behavioral ratings indicating a significant (P < 0.05) reduction in canine stress compared to the placebo group for at least one time point. Additional research investigating a range of dog populations and stressors is required to fully understand the complex effect of CBD on canine emotional wellbeing.

The impact of single-dose trazodone administration on plasma endogenous adrenocorticotropic hormone and serum cortisol concentrations in healthy dogs

BACKGROUND

Conditions affecting the hypothalamic-pituitary-adrenal (HPA) axis are common in dogs. Testing the function of the HPA axis includes measurement of endogenous adrenocorticotropic hormone (eACTH) and performance of an adrenocorticotropic hormone (ACTH) stimulation test. Trazodone is commonly administered to dogs to decrease stress. In humans, trazodone significantly decreases plasma cortisol concentration via alpha-1 adrenergic activity.

OBJECTIVES

Determine the influence of trazodone on eACTH and serum cortisol concentrations in healthy dogs.

ANIMALS

Fourteen healthy, adult, companion dogs.

METHODS

Prospective, randomized placebo-controlled study. Trazodone (8-10 mg/kg) or placebo was administered PO 1 hour before eACTH measurement and ACTH stimulation testing. After a ≥7-day wash-out period, dogs received the opposite treatment. Differences in eACTH, pre- and post-ACTH stimulation cortisol concentrations, and delta (difference between pre- and post-ACTH) cortisol concentrations were analyzed using a paired t or signed-rank test with a P < .05 significance level.

RESULTS

The eACTH concentrations were not significantly different (P = .23) between treatments. Similarly, no significant differences were found in the pre-ACTH cortisol concentrations between treatments (P = .40). Post-ACTH cortisol concentrations (P = .05) and delta cortisol concentrations (P = .04) were significantly lower when the dogs were treated with trazodone.

CONCLUSIONS

Preliminary data suggest trazodone administration dampens the adrenocortical response to stimulation in healthy dogs. If similar effects are found in dogs with adrenal disease, the use of trazodone may affect diagnosis and clinical decision making in these populations.

Adverse effects of trazodone in dogs on primary hemostasis and electrocardiogram: A single-blinded placebo-controlled crossover study

BACKGROUND

Trazodone is a serotonin antagonist/reuptake inhibitor medication commonly used for anxiety in dogs. Therapy with selective serotonin reuptake inhibitors in humans is associated with bleeding disorders and increased arrhythmogenesis.

HYPOTHESIS/OBJECTIVES

To evaluate markers of primary hemostasis and corrected QT (cQT) interval in dogs before and after oral administration of standard dosages of trazodone or placebo.

ANIMALS

Fifteen apparently healthy, client-owned dogs.

METHODS

A single-blinded, randomized placebo-controlled crossover study was performed. Dogs were administered trazodone (5 to 7.5 mg/kg PO Q12h) or placebo. [Correction added after first online publication on 14 October 2023. In the abstract (methods) section (57.5 mg/kg PO Q12h) changed as (5 to 7.5 mg/kg PO Q12h).] Buccal mucosal bleeding time (BMBT), platelet count, platelet aggregation via Plateletworks, PFA-100 closure time and cQT interval were measured. A Shapiro-Wilk test was performed followed by either a paired t test or a Wilcoxon signed-rank test.

RESULTS

No significant difference was detected in the BMBT, PFA-100 closure times, platelet counts, and cQT interval between trazodone or placebo. However, using Plateletworks, there was a significant decrease in platelet aggregation after administration of trazodone (95%; 81-97 vs 62%; 39-89, P = .002) and not placebo (95%; 81-97 vs 91%; 81-96, P = .21).

CONCLUSIONS

It is unknown if this represents a clinically relevant change or if dogs with preexisting impairment in primary hemostasis or receiving higher dosages or longer durations of trazodone could have a more substantial change in hemostatic variables.

EFFECTS OF A SINGLE ORAL DOSE OF TRAZODONE ON BEHAVIOR AND SERUM CORTISOL LEVELS IN BLUE WILDEBEEST (CONNOCHAETES TAURINUS)

Trazodone is a dose-dependent serotonin antagonist and agonist used to treat anxiety-related conditions. Trauma has been identified as the leading cause of morbidity and mortality in several nondomestic ruminant species and can be exacerbated by stress. In a recent study in domestic goats (Capra aegagrus hircus), trazodone reduced activity levels without adverse effects. Trazodone could allow for safer capture and handling in nondomestic ruminant species. The objectives of this study were to identify a dose of trazodone that decreases activity levels in captive blue wildebeest (Connochaetes taurinus) and to evaluate its safety and its effects on serum cortisol levels following a routine veterinary procedure. A pilot study using ethograms identified a group fed 15 mg/kg oral dose of trazodone as effective to reduce activity levels. Over 6 h, this dose resulted in a 111% increase in time spent sleeping or resting (P = 0.0003), a 41% increase in time spent lying down (P = 0.0016), a 64% reduction in time spent moving (P= 0.005), and a 65% reduction in time spent being vigilant (P= 0.026). Systemic absorption of trazodone was identified when plasma concentrations were measured after 2 h (95 ± 48 µg/L). Serum cortisol levels during a routine venipuncture event were not significantly different following trazodone administration (P > 0.05). Mild hyporexia was the only adverse effect noted at 15 mg/kg and was absent at a 12 mg/kg dose. Trazodone appears safe and promising to decrease activity in blue wildebeest and might thus have a positive effect on nondomestic ruminant welfare and the safety of veterinary procedures.

Effects of trazodone administration on the neurologic examination in healthy dogs

BACKGROUND

Trazodone is an anxiolytic used PO to decrease anxiety in dogs. Whether or not trazodone affects the neurologic examination in dogs has not been previously reported.

OBJECTIVE

Investigate whether trazodone administration is associated with changes in the neurologic examination in healthy dogs.

ANIMALS

Thirty-two healthy dogs between 1 and 6 years old with no previously diagnosed medical conditions and perceived by their owners as neurologically normal.

METHODS

Baseline sedation and anxiety assessments and neurologic examination were performed on each dog, followed by trazodone administration (6.25-8.60 mg/kg PO). The sedation and anxiety assessments and neurologic examination were repeated 2.5 hours after trazodone administration. The examinations were performed by a single board-certified veterinary neurologist and were video-recorded. The videos were randomized and reviewed by a different neurologist, blinded to the previous evaluations, who scored the examinations.

RESULTS

Seven of 32 (22%) dogs had worse scores on their neurologic examination after receiving trazodone, manifesting as new or progressive PR deficits. Although not clinically relevant, 18.7% of the dogs had consciousness levels that changed from bright, alert, responsive to quiet, alert, responsive after trazodone administration. No other changes were observed on neurologic examination. Sedation and anxiety scores were significantly different after trazodone administration compared to before (P < .001 and P < .001, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Most dogs did not have changes on neurologic examination after trazodone administration. However, approximately 20% of dogs had new or worsening PR deficits after receiving trazodone. Ideally, trazodone should not be given before neurologic examination in dogs.

Effects of trazodone on behavioral and physiological signs of stress in dogs during veterinary visits: a randomized double-blind placebo-controlled crossover clinical trial

OBJECTIVE

To determine whether a single dose of trazodone administered to dogs before a veterinary visit reduced their behavioral and physiologic signs of stress and owners' stress during veterinary visits.

SAMPLE

20 dogs and their owners.

PROCEDURES

In this randomized double-blinded placebo-controlled crossover clinical trial, dogs with a history of anxiety during veterinary visits were scheduled for 2 veterinary visits 1 week apart and randomly assigned to receive a single oral dose of either trazodone (9 to 12 mg/kg) or a placebo 90 minutes before transport to the veterinary clinic for alternate visits between September 21 and November 3, 2019. For each visit, we collected and assessed owner-completed surveys of dog stress score (DSS) and owner stress score; various investigator-reported scores, including from video-recorded behavior analyses; and patient-related physiologic data.

RESULTS

Dogs treated with trazodone versus placebo had lower mean DSSs, assessed by owners for physical examination and assessed by video analysis for time spent in the examination room; lower mean SD of normal-to-normal intervals, root mean square of successive heartbeat interval difference, and respiratory rate; and higher mean heart rate. No meaningful differences were observed in other behavioral or physiologic outcomes, including serum cortisol concentrations.

CLINICAL RELEVANCE

A single dose of trazodone before transport reduced signs of stress during veterinary visits for dogs in the present study and may be useful as an anti-anxiety medication for similarly affected dogs, potentially resulting in higher-quality clinical examinations and improved patient welfare.

Miniature Companion Pig Sedation and Anesthesia

With their increase in popularity in North America as pets, miniature companion pigs are in need of veterinary professionals familiar with sedation and anesthesia for the species. This article provides a review of the agents used for sedation, premedication, induction, and maintenance of anesthesia for miniature companion pigs. This review also covers species-specific anatomic and physiologic factors of miniature companion pigs with respect to administration of anesthetics, endotracheal intubation, anesthetic maintenance, and common complications so that the reader can make an informed anesthetic plan for the species.

Efficacy of a Single Dose of Pregabalin on Signs of Anxiety in Cats During Transportation-A Pilot Study

Objectives: The aim of this clinical pilot study was to evaluate the dosage, efficacy, and clinical safety of a single oral dose of pregabalin in cats that experience fear and anxiety when placed into a carrier and transported by car.

Methods: Thirteen client-owned cats were enrolled in a blinded, randomized, crossover study with three treatment days approximately 1 week apart. The cats were assigned to receive pregabalin oral solution at dosages of 5 and 10 mg/kg and placebo in a randomized order, one treatment per week. Treatment was administered ~90 min before placing the cat into a carrier and starting transportation. Efficacy was assessed by the owners using a categorical scale and, based on video recordings, by an external observer, both blinded to the treatment.

Results: Owners assessed that cats given pregabalin displayed less vocalization, restlessness, and panting during transportation than did cats given placebo. Correlation between owners' and external observer's assessment of the overall treatment effect was good (0.63, p < 0.01), which confirms the owners' ability to observe reliably their own cat's behavior. Transient mild ataxia was the most common adverse event reported. The human commercial formulation used in this study was found difficult or very difficult to administer by 79% of the owners.

Conclusions and Relevance: Based on results of this pilot study, a single oral dose of pregabalin was well tolerated and decreased signs of anxiety and fear associated with car transportation in cats, as evaluated by blinded owners and external observer. The use of pregabalin prior to traveling may improve cat welfare and compliance for transportation. Further studies are needed to investigate the use of oral pregabalin in cats to alleviate signs of anxiety and fear associated with transportation and sequelae, like veterinary visits, and to develop a more user-friendly formulation.

PHARMACOKINETICS AND CLINICAL EFFECTS OF A SINGLE ORAL DOSE OF TRAZODONE IN THE DOMESTIC GOAT (CAPRA HIRCUS) AS A MODEL FOR WILD RUMINANTS

Trazodone is an antianxiety medication commonly used in human and veterinary medicine. Stress-related trauma is the leading cause of morbidity and mortality in wild ruminant species. Trazodone could reduce stress and allow safer capture and handling, thus having a positive effect on their welfare. The objective of this study was to describe the clinical effects and pharmacokinetic profile of an oral dose of trazodone in domestic goats (Capra hircus) as a model for wild ruminants. A pilot study using ethograms and accelerometers identified an oral dose of 10 mg/kg as optimal to reduce activity levels. This dose resulted in a 502% increase in time spent sleeping (P=0.0016) and a 623% increase in time spent lying down (P=0.01). Additionally, there were reductions of 72% in time spent grooming (P=0.02), 49% in time spent moving (P=0.01), and 87% in time spent observing (P=0.0002). Activity levels were significantly decreased by 31% for 4 hr following administration (P=0.049). There were no observed adverse effects. Time spent eating or ruminating was not affected by trazodone administration (P > 0.05). The pharmacokinetics of trazodone following a single oral dose of 10 mg/kg in 7 goats was assessed. All animals achieved plasma concentrations over 130 ng/ml, a level considered therapeutic in humans and dogs, for a mean of 6.4 ± 5.0 hr. Mean terminal half-life was 10.55 ± 6.80 hr. All goats achieved maximum concentration within 5-15 min and still had detectable plasma levels at 24 hr. Trazodone appears promising to decrease stress in exotic ruminant species. Further research is warranted to establish its efficacy in other ruminant species and clinical situations.

Suspected hepatotoxicity secondary to trazodone therapy in a dog

OBJECTIVE

To describe a case of suspected hepatotoxicity in a dog secondary to administration of trazodone.

CASE SUMMARY

A 6-year-old, neutered, mixed breed dog was evaluated for a progressive increased liver enzyme activity over a 6-week period. The patient originally presented for raisin toxicosis, and hence, was having serial blood work monitoring performed. Trazodone was initially started at that time due to severe separation anxiety while hospitalized (consistently 5 out of 7 days of the week, for a 6-week duration). Due to continued increased liver enzyme activity, extensive workup was performed which included abdominal ultrasound, leptospirosis titers, bile acids, and liver biopsies. Histopathologic findings were consistent with acute hepatotoxicity. In the absence of other toxicants and the close proximity to drug administration, a drug-induced hepatopathy secondary to trazodone was presumed. Following discontinuation of trazodone therapy, the hepatopathy completely resolved and the patient fully recovered.

NEW OR UNIQUE INFORMATION PROVIDED

While acute hepatotoxicity has been reported in human medicine secondary to the administration of trazodone, this is the first reported case of suspected hepatotoxicity in a dog secondary to trazodone therapy. Veterinary professionals should be aware of the rare potential adverse effect that may be seen in canine patients secondary to trazodone therapy. Appropriate clinicopathologic monitoring should occur in patients on chronic trazodone therapy.

Pharmacokinetics and efficacy of trazodone following rectal administration of a single dose to healthy dogs

OBJECTIVE

To determine the pharmacokinetics and efficacy of trazodone following rectal administration of a single dose to healthy dogs.

ANIMALS

6 healthy adult dogs.

PROCEDURES

Each dog received a single dose of trazodone (approx 8 mg/kg) per rectum. Trazodone tablets were crushed into a powder, mixed with 5 mL of tap water, and injected into the rectum via a red rubber catheter. Sedation scores were assigned, and blood samples were collected for determination of plasma trazodone concentration at predetermined times before and after drug administration. Pharmacokinetic parameters were estimated by noncompartmental analysis.

RESULTS

Plasma trazodone concentration remained below the detection limit for 1 dog even though it became moderately sedate. Median (interquartile [25th to 75th percentile] range [IQR]) maximum plasma trazodone concentration and volume of distribution and clearance corrected for bioavailability were 1.00 μg/mL (0.66 to 1.40 μg/mL), 10.3 L/kg (7.37 to 14.4 L/kg), and 639 mL/kg/h (594 to 719 mL/kg/h), respectively. Median time to maximum plasma trazodone concentration and elimination half-life were 15 minutes (range, 15 to 30 minutes) and 12 hours (IQR, 7.99 to 12.7 hours), respectively. All dogs became mildly or moderately sedate, and the extent of sedation was maximal at a median of 30 minutes (IQR, 30 to 60 minutes) after trazodone administration. No adverse effects were observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Rectal administration of trazodone may be a viable option for sedation and treatment of anxiety in dogs for which administration of sedatives and anxiolytics by other routes is contraindicated. Further research is necessary to better elucidate the pharmacokinetics and efficacy of trazodone following rectal administration and determine optimal dosing.

Evaluation of repeated dosing of a dexmedetomidine oromucosal gel for treatment of noise aversion in dogs over a series of noise events

Background

Noise aversion is a common behavioural disorder in dogs; affected dogs show fear behaviours in response to noise stimuli. Pharmacological treatment is effective for many dogs; clinical reports suggest anxiolytic treatment lowers the need for treatment over time. We aimed to evaluate the effect of dexmedetomidine oromucosal gel for dogs with noise aversion over a series of noise events. Furthermore, we evaluated burden of care for owners of dogs with noise aversion via questionnaire.

Methods

Owners of enrolled dogs completed records for 10 noise events indicating whether their dog received dexmedetomidine gel and pretreatment and post-treatment anxiety scores; adverse events were noted. Owners were queried about burden of care.

Results

Twenty-two client-owned dogs completed recordings for 10 events. Logistic regression results showed a significant effect for time of event with decreased probability of receiving treatment for subsequent events (OR=0.75, P=0.0017). Within an event, significant improvement in anxiety was seen (median improvement 11 points; paired Wilcoxon; P<0.0001). We found overall burden of care was manageable, yet many owners agreed with statements regarding frustration (42 per cent), stress (46 per cent), guilt (42 per cent) and sadness (75 per cent) about their dog’s condition.

Conclusions

Repeated use of dexmedetomidine gel for noise events resulted in decreased need for administration. Burden of care is important to discuss with clients.

The Impact of Feeding Cannabidiol (CBD) Containing Treats on Canine Response to a Noise-Induced Fear Response Test

Interest is increasing regarding use of Cannabidiol (CBD) in companion animals due to anecdotal evidence of beneficial behavioral and health effects. The purpose of this investigation was to evaluate the influence of CBD on behavioral responses to fear-inducing stimuli in dogs. Sixteen dogs (18.1 ± 0.2 kg) were utilized in a replicated 4 × 4 Latin square design experiment with treatments arranged in a 2 × 2 factorial, consisting of control, 25 mg CBD, trazodone (100 mg for 10–20 kg BW, 200 mg for 20.1–40 kg BW), and the combination of CBD and trazodone. A fireworks model of noise-induced fear was used to assess CBD effectiveness after 7 d of supplementation. Each test lasted a total of 6 min and consisted of a 3 min environmental habituation phase with no noise and a 3 min noise phase with a fireworks track. Plasma was collected 1 h before, immediately after, and 1 h following testing for cortisol analysis. Behaviors in each 3 min block were video recorded, and heart rate (HR) sensors were fitted for collection of HR and HR variability parameters. Research personnel administering treats and analyzing behavioral data were blinded as to the treatments administered. Data were tested for normality using the UNIVARIATE procedure in SAS, then differences examined using the MIXED procedure with fixed effects of treatment, period, time, and treatment x time interaction. Inactivity duration and HR increased during the first minute of the fireworks track compared with 1 min prior (P < 0.001 and P = 0.011, respectively), indicating the fireworks model successfully generated a fear response. Trazodone lowered plasma cortisol (P < 0.001), which was unaffected by CBD (P = 0.104) or the combination with CBD (P = 0.238). Neither CBD nor trazodone affected the duration of inactivity (P = 0.918 and 0.329, respectively). Trazodone increased time spent with tail relaxed (P = 0.001). CBD tended to increase HR (P = 0.093) and decreased the peak of low- and high-frequency bands (LF and HF, P = 0.011 and 0.022, respectively). These results do not support an anxiolytic effect of CBD in dogs given 1.4 mg CBD/kg BW/d.

Mental Health Disease or Preventable Problem? Australian Dog Trainers' Opinions about Canine Separation Anxiety Differ with Training Style

Separation anxiety is common. Many dog owners do not seek help from a veterinarian but might consult a trainer. The objective of this study was to investigate Australian trainers' opinions about separation anxiety. An online survey was distributed via training organisations, resulting in 63 completed surveys. Descriptive statistics and Fisher's exact tests were applied. Respondents were grouped into reward-based (n = 41) and balanced (n = 22) trainers. Most trainers (82.5%) used multiple methods to identify separation anxiety but only 7.9% referred to a veterinarian for diagnosis. Reward-based trainers ranked assistance from a veterinarian and owner's willingness to try medication as more important than balanced trainers (p < 0.05). More balanced trainers reported that medication was rarely necessary in the cases they saw: 50% balanced compared with 4.9% reward-based trainers, with 95% CIs of [28.2, 71.8] and [0.6, 16.5], respectively. Almost all (95.5%) balanced trainers believed separation anxiety was preventable compared with 52.6% of reward-based trainers (p < 0.05). We conclude that opinions about separation anxiety varied between reward-based and balanced trainers. Trainers are not taught, expected, or legally allowed to diagnose anxiety disorders. This study showed that balanced trainers were less likely to recommend involvement of veterinarians who can make a diagnosis and rule out other causes of observed behaviours.

Progress in Veterinary Behavior in North America: The Case of the American College of Veterinary Behaviorists

The American College of Veterinary Behavior has grown in number and in expertise over the past quarter century. There are now 86 diplomates, at least three textbooks on treating behavior problems, and a text on veterinary psychopharmacology. Although veterinary behavior began in veterinary colleges, the majority of residents are now trained in non-conforming programs. Many more diplomates practice privately in specialty clinics or as separate businesses. Progress has been made in both diagnosis and treatment with polypharmacy, resulting in successful outcomes for many dogs and cats suffering from separation anxiety, fear, or aggression.

Coughing in Small Animal Patients

Cough is one of the most common complaints in human medicine. In veterinary medicine cough is equally frequent and plays a significant role in an owner's perception of their pet's quality of life. In human and veterinary medicine, therapy for chronic cough is often ineffective. The complexity of the cough pathway and species differences have made it difficult to develop an effective antitussive agent for veterinary patients. The few effective antitussive agents currently available are associated with significant adverse effects. Fortunately, several promising drugs currently being studied in human clinical trials may offer options for use of novel antitussive therapies in small animal patients. This article reviews current understanding about cough pathophysiology, diagnostic strategies used to uncover underlying etiology of cough, and examines available options for controlling cough, including novel antitussive therapies used in human medicine.

Pharmacokinetics and pharmacodynamic effects of oral transmucosal and intravenous administration of dexmedetomidine in dogs

OBJECTIVE

To determine pharmacokinetic and pharmacodynamic properties of the injectable formulation of dexmedetomidine administered via the oral transmucosal (OTM) route to healthy dogs.

ANIMALS

6 healthy dogs.

PROCEDURES

Injectable dexmedetomidine was administered IV (5 μg/kg) or via the OTM route (20 μg/kg) in a blinded, single-observer, randomized crossover study. Dogs received dexmedetomidine and a sham treatment at each administration. Serial blood samples were collected from a catheter in a saphenous vein. Heart rate, respiratory rate, and subjective sedation score were assessed for 24 hours after administration. Plasma samples were analyzed for dexmedetomidine concentrations by use of ultraperformance liquid chromatography-tandem mass spectrometry.

RESULTS

For the OTM route, the mean ± SD maximum plasma concentration was 3.8 ± 1.3 ng/mL, which was detected 73 ± 33 minutes after administration. The mean maximum concentration for the IV dose, when extrapolated to the time of administration, was 18.6 ± 3.3 ng/mL. The mean terminal-phase half-life was 152 ± 146 minutes and 36 ± 6 minutes for OTM and IV administration, respectively. After IV administration, total clearance was 8.0 ± 1.6 mL/min/kg and volume of distribution at steady state was 371 ± 72 mL/kg. Bioavailability for OTM administration of dexmedetomidine was 11.2 ± 4.5%. Peak sedation scores did not differ significantly between routes of administration. Decreases in heart rate, respiratory rate, and peak sedation score were evident sooner after IV administration.

CONCLUSIONS AND CLINICAL RELEVANCE

OTM administration of the injectable formulation of dexmedetomidine resulted in a similar degree of sedation and prolonged duration of action, compared with results for IV administration, despite relatively low bioavailability.

Psychogenic stress in hospitalized veterinary patients: Causation, implications, and therapies

OBJECTIVE

To review the sources, adverse effects, diagnosis, treatment, and prevention of psychogenic stress in hospitalized human and veterinary patients.

DATA SOURCES

Data were collected by searching PubMed for veterinary and human literature from the past 10 years.

HUMAN DATA SYNTHESIS

Psychogenic stress has been linked to immune suppression; gastrointestinal, cardiovascular, and cutaneous diseases; delayed wound healing; alterations in pain perception; and neurologic impairment. Sources of psychogenic stress include environmental alterations such as excessive noise and light, social and physical factors, sleep disruption, drugs, and underlying disease. Nonpharmacologic options for stress reduction include environmental and treatment modifications, music therapy, and early mobilization. Pharmacologic options include sedation with benzodiazepines and dexmedetomidine. Trazodone and melatonin have been examined for use in sleep promotion but are not currently recommended as standard treatments in ICU.

VETERINARY DATA SYNTHESIS

Activation of the stress response in veterinary patients is largely the same as in people, as are the affected body systems. Possible sources of stress can include social, physical, and environmental factors. No gold standard currently exists for the identification and quantification of stress. A combination of physical examination findings and the results of serum biochemistry, CBC, and biomarker testing can be used to support the diagnosis. Stress scales can be implemented to identify stressed patients and assess severity. Nonpharmacologic treatment options include low-stress handling, pheromones, environmental modifications, and sleep promotion. Pharmacologic options include trazodone, benzodiazepines, dexmedetomidine, and melatonin.

CONCLUSION

The prevalence and clinical significance of psychogenic stress in hospitalized veterinary patients is unknown. Future studies are needed to specifically examine the causative factors of psychogenic stress and the effects of various therapies on stress reduction. The recognition and reduction of psychogenic stress in veterinary patients can lead to improvements in patient care and welfare.

Determination of the pharmacokinetics of a single oral dose of trazodone and its effect on the activity level of domestic pigeons (Columba livia)

OBJECTIVE

To determine the pharmacokinetics of a single oral dose of trazodone and its effect on the activity of domestic pigeons (Columba livia).

ANIMALS

6 healthy adult male domestic pigeons.

PROCEDURES

During the first of 3 experiments, birds received orally administered trazodone at doses ranging from 3 to 30 mg/kg to determine the dose for subsequent experiments. During the second experiment, each bird received 1 dose of trazodone (30 mg/kg, PO). Blood was collected for determination of plasma trazodone concentration before and at predetermined times for 24 hours after drug administration. Pharmacokinetic parameters were calculated by noncompartmental analysis. During experiment 3, birds were instrumented with ultralightweight accelerometers and received orally administered trazodone (30 mg/kg) or an equal volume of water twice at a 48-hour interval. Activity of birds was monitored for 24 hours after administration of each treatment.

RESULTS

No adverse effects were observed. Mean ± SD terminal half-life of trazodone was 5.65 ± 1.75 hours. Plasma trazodone concentrations remained > 0.130 μg/mL for approximately 20 hours. Trazodone did not affect the activity of birds during the first 2 and 15 hours after administration.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that oral administration of 1 dose (30 mg/kg) of trazodone to healthy pigeons was safe and resulted in plasma drug concentrations that were similar to those considered therapeutic in humans and dogs for up to 20 hours. Further research is necessary to characterize the pharmacokinetics for repeated doses as well as the clinical effects of trazodone in birds with behavior problems.

Effect of oral trazodone on the minimum alveolar concentration of isoflurane in dogs

OBJECTIVE

To determine the effect of oral trazodone on the minimum alveolar concentration (MAC) of isoflurane in dogs.

STUDY DESIGN

Prospective blinded, single-observer, randomized crossover experimental study.

ANIMALS

Six adult (age 6.8 ± 1.6 months) healthy dogs (three males and three females), weighing 24.8 ± 3.4 kg (mean ± standard deviation).

METHODS

Each dog was anesthetized twice with a minimum of 7 days between anesthetic episodes. Dogs were randomly assigned to be administered two treatments in a crossover design: premedication with trazodone (8 mg kg^-1; TRAZ-ISO) orally 2 hours prior to an anesthetic episode or no (ISO). Dogs were anesthetized with intravenous propofol (6 mg kg^-1) and isoflurane in >95% oxygen. Isoflurane MAC was determined using an iterative bracketing technique with electrodes placed in the buccal mucosa. Hemodynamic variables were compared at the lowest end-tidal isoflurane concentration at which each dog did not respond. A paired t test was used to assess the effect of treatment on outcome variables with significance set to a value of p < 0.05.

RESULTS

The MAC concentration (mean ± standard deviation) in dogs administered TRAZ-ISO was 0.85 ± 0.17% compared with 1.02 ± 0.11% in those administered ISO (p = 0.01, 95% confidence interval -0.25 to -0.05), resulting in a mean MAC reduction of 17 ± 12%. There were no differences in hemodynamic variables between treatments.

CONCLUSIONS AND CLINICAL RELEVANCE

Premedication of dogs with oral trazodone (8 mg kg^-1) 2 hours prior to anesthetic induction has a significant isoflurane MAC sparing effect with no significant observed hemodynamic benefit.

Pharmacokinetics, pharmacodynamics and clinical use of trazodone and its active metabolite m-chlorophenylpiperazine in the horse

Trazodone is a serotonin receptor antagonist and reuptake inhibitor used extensively as an anxiolytic in human and small animal veterinary medicine. The aims of this study were to determine the pharmacokinetics of oral trazodone in experimental horses and to evaluate the effect of oral trazodone in clinical horses. Six experimental horses were administered trazodone at 7.5 or 10 mg/kg. Plasma concentrations of trazodone and its metabolite (m-CPP) were determined via UPLC-MS/MS. Noncompartmental pharmacokinetic analysis, sedation and ataxia scores were determined. Trazodone was rapidly absorbed after oral administration with a maximum concentration of 2.5-4.1 μg/ml and half-life of the terminal phase of approximately 7 hr. The metabolite was present at low levels in all horses, representing only 2.5% of the total area under the curve. In experimental horses, concentration-dependent sedation and ataxia were noted, lasting up to 12 hr. For clinical cases, medical records of horses treated with trazodone for various abnormal behaviours were reviewed and data were summarized. Trazodone was successful in modifying behavioural problems to some degree in 17 of 18 clinical cases. Tolerance and subsequent lack of drug effect occurred in two of 18 clinical cases following 14 or 21 days of use. In both populations of horses, adverse effects attributed to trazodone include oversedation, muscle fasciculations and transient arrhythmias.

Medication for Behavior Modification in Birds

The use of behavior modifying drugs may be considered in birds with behavior problems, especially those refractory to behavior modification therapy and environmental management. To accomplish behavior change, a variety of drugs can be used, including psychoactive drugs, hormones, antihistamines, analgesics, and anticonvulsants. Because their prescription to birds is off-label, these drugs are considered appropriate only when a sound rationale can be provided for their use. This requires a (correct) behavioral diagnosis to be established. In addition, regular monitoring and follow-up are warranted to determine the efficacy of the treatment and evaluate the occurrence of potential adverse side effects.

Use of oral trazodone for sedation in cats: a pilot study

OBJECTIVES

Resistance to transportation and stressful veterinary visits are major causes for a decrease in feline veterinary care. Few options exist for oral sedatives to reduce cats' anxiety prior to veterinary visits. The purpose of this study was to evaluate the safety and efficacy of oral trazodone for use as a single dose agent for sedation in cats.

METHODS

Six laboratory cats were given single 50, 75 and 100 mg doses of trazodone and placebo. Trazodone 100 mg and placebo treatments were randomized. Pre- and post-study laboratory values and physical examinations were compared. During each 4 h period post-treatment, sedation was measured via accelerometers and video observations scored by an observer blinded to treatment. Examinations were performed on the cats 90 mins after treatment, and their behavioral responses scored by the same blinded observer.

RESULTS

No adverse effects or changes in physical examinations or laboratory values were detected as a result of trazodone administration. Accelerometer data showed trazodone 50, 75 and 100 mg caused sedation as measured by activity reduction (83%, 46% and 66%, respectively). In contrast, there was a 14% activity increase after placebo. There was a significant reduction in video observation scores when cats were given trazodone 100 mg compared with placebo. Mean latency to peak sedation for trazodone 100 mg occurred at 2 h. Scores for behavioral response to examination, performed at 90 mins post-treatment, were not significantly different between cats receiving trazodone 100 mg and placebo.

CONCLUSIONS AND RELEVANCE

Trazodone was well tolerated in this population of cats and caused appreciable sedation at all doses. Behavior during examination was not significantly different when cats received trazodone 100 mg compared with placebo. Further studies are recommended to investigate the use of oral trazodone in cats for the purpose of decreasing anxiety assocaited with transportation and examination.

Use of trazodone to facilitate postsurgical confinement in dogs

OBJECTIVE

To investigate the safety and efficacy of oral administration of the serotonin antagonist and reuptake inhibitor trazodone hydrochloride to facilitate confinement and calming after orthopedic surgery in dogs.

DESIGN

Prospective open-label clinical trial.

ANIMALS

36 client-owned dogs that underwent orthopedic surgery.

PROCEDURES

Starting the day after surgery, dogs were administered trazodone (approx 3.5 mg/kg [1.6 mg/lb], PO, q 12 h) with tramadol (4 to 6 mg/kg [1.8 to 2.7 mg/lb], PO, q 8 to 12 h) for pain management. After 3 days, administration of tramadol was discontinued, and the trazodone dosage was increased (approx 7 mg/kg [3.2 mg/lb], PO, q 12 h) and maintained for at least 4 weeks. If needed, trazodone dosage was increased (7 to 10 mg/kg [3.2 to 4.5 mg/lb], PO, q 8 h). Owners completed electronic surveys rating their dogs' confinement tolerance, calmness or hyperactivity level, and responses to specific provocative situations prior to surgery and 1, 2, 3, and 4 weeks after surgery and at the postsurgery evaluation (at 8 to 12 weeks).

RESULTS

Most (32/36 [89%]) of owners reported that their dogs, when given trazodone during the 8 to 12 weeks following orthopedic surgery, improved moderately or extremely with regard to confinement tolerance and calmness. Trazodone was well tolerated, even in combination with NSAIDs, antimicrobials, and other medications; no dogs were withdrawn from the study because of adverse reactions. Owner-reported median onset of action of trazodone was 31 to 45 minutes, and median duration of action was ≥ 4 hours.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that oral administration of trazodone was safe and efficacious and may be used to facilitate confinement and enhance behavioral calmness of dogs during the critical recovery period following orthopedic surgery.