Pharmacological appetite stimulation: rational choices in the inappetent cat

Use of Gabapentin or Alprazolam in Cats during Postoperative, Short-Term Hospitalization

This prospective, randomized study aimed to assess the anxiolytic efficacy of gabapentin or alprazolam in cats during short-term postoperative hospitalization. Sixty cats were randomly assigned to three groups (gabapentin-treated [100 mg per cat], alprazolam-treated [0.125 mg per cat], or placebo-treated), with treatments administered twice daily for two days. Stress levels were evaluated using Cat Stress Scores, serum cortisol, and glucose concentrations. Pain scores, food consumption, and adverse effects such as sedation were also monitored. Fifty-five cats completed the study. Both medications demonstrated similar reductions in stress levels. Cats receiving gabapentin had lower pain scores, while those receiving alprazolam exhibited significantly increased food intake on the first postoperative day. However, both medications resulted in comparable levels of sedation. In the context of postoperative hospitalization, pharmacological intervention with anxiolytics could be effective in reducing stress levels. Despite potential side effects, gabapentin and alprazolam may contribute to an improved quality of short-term hospitalization for cats.

Feline Aortic Thromboembolism: Recent advances and future prospects

PRACTICAL RELEVANCE

Feline aortic thromboembolism (FATE) is commonly encountered in clinical medicine, especially in emergency situations. This often devastating syndrome usually develops secondarily to severe heart disease, and has short- and long-term consequences.

CLINICAL FEATURES

The clinical presentation of FATE is consistent with peripheral ischemic neuropathy, usually in both pelvic limbs. Diagnosis is relatively straightforward, but can be assisted with Doppler ultrasound, point-of-care ultrasound or infrared thermal imaging.

RECENT ADVANCES AND FUTURE PROSPECTS

Interpretation of survival rates in cats with FATE has been hampered by historically high admission euthanasia, but recent studies suggest a survival rate with supportive care of 30-40%. Moreover, with advances in post-FATE thromboprophylaxis, median survival times of over 1 year are being achieved. Future directions include use of thrombolytic agents and treatment of common FATE sequelae such as acute kidney injury and reperfusion injury.

OUTLINE

This article, aimed at small animal veterinarians, including emergency practitioners, reviews key aspects of the clinical presentation, diagnosis and treatment options for FATE, with a view to guiding client and veterinarian decision-making. Three case studies are included to illustrate the practical application of information presented in the review.

EVIDENCE BASE

There are limited prospective studies on FATE, although the recent literature reflects a resurgence in clinical research interest in the past few years. Advances in FATE treatment will benefit many cats and it is important that research efforts continue to identify appropriate treatment modalities.

Bradyarrhythmia after treatment with atenolol and mirtazapine in a cat with hypertrophic cardiomyopathy

A nine-year-old spayed female domestic shorthair cat with a previous diagnosis of hypertrophic cardiomyopathy and treated for one month with atenolol (6.25 mg q 12 h) was referred for respiratory distress and anorexia. The cat was diagnosed with pulmonary oedema secondary to obstructive hypertrophic cardiomyopathy. After stabilisation, she was discharged with furosemide (1 mg/kg q 12 h), clopidogrel (18.75 mg q 24 h), atenolol (6.25 mg q 12 h), and mirtazapine (2 mg/cat q 24 h) to increase appetite. At recheck, the cat was lethargic and presented with severe bradycardia with a junctional escape rhythm and ventriculoatrial conduction. The mirtazapine was discontinued due to its possible side-effects on cardiac rhythm. After three days, the atenolol was halved because the bradyarrhythmia was still present. After 10 days, the rhythm returned to sinus; atenolol was reintroduced twice daily with no further side-effects. The absence of a sinus rhythm with a junctional escape rhythm and P' retroconduction is compatible with a third-degree sinus block or a sinus standstill; the differentiation of these rhythm disturbances is impossible, based on the surface electrocardiogram (ECG). The sinus rhythm was restored after mirtazapine was withdrawn. However, it is not possible to rule out the role of the atenolol or the combined effect of the two drugs. The cat was affected by hypertrophic cardiomyopathy, and the role of myocardial remodelling cannot be excluded. This is the first time that a bradyarrhythmia consequent to the treatment with atenolol and mirtazapine was described in a cat.

Insights on discovery, efficacy, safety and clinical applications of ghrelin receptor agonist capromorelin in veterinary medicine

Growth hormone and insulin like growth factor-1 plays an important role in the regulation of body composition and metabolism. Growth Hormone is released from the pituitary through a specific G-protein coupled receptor (GPCR) called growth hormone secretagogue receptor 1a expressed in the hypothalamus. Ghrelin is a peptide hormone released from the cells in the stomach, which stimulates appetite and food intake in mammals, regulates gut motility, gastric acid secretion, taste sensation, circadian rhythm, learning and memory, oxidative stress, autophagy, glucose metabolism etc. When the release of the endogenous ligand GHSR-1a, i.e., ghrelin is malfunctioned or stopped, external substitutes are administrated to induce the stimulation of growth hormone and appetite. A class of compound known as ghrelin receptor agonists are developed as an external substitute of ghrelin for regulation and stimulation of growth hormone in frailty, for body weight gain, muscle mass gain, prevention of cachexia and for the treatment of chronic fatigue syndromes. Capromorelin [Entyce™ (Aratana Therapeutics, Leawood, KS, USA)] is the only FDA (Food and Drug Administration) approved (May 2016) drug used for stimulating appetite in dogs and was marketed in the fall of 2017. In 2020, USFDA approved Capromorelin [Elura™ (Elanco US Inc.)] for the management of weight loss in chronic kidney disease of cats. This article reviews the discovery of the ghrelin receptor agonist capromorelin, its efficacy, safety, clinical applications and aims to delineate its further scope of use in veterinary practice.

Use of feeding tubes in 112 cats in an internal medicine referral service (2015-2020)

OBJECTIVES

The aims of this study were to describe diseases, complications and outcomes associated with the use of feeding tubes in a population of sick cats with appetite disturbance managed at an internal medicine referral service.

METHODS

Clinicopathological data from cats receiving nasoenteral (NE) or oesophagostomy (O) tubes were studied. Cats were categorised according to their underlying disease and divided into subgroups (NE or O tube). The following factors associated with survival were analysed: disease category, type of tube and return to appetite.

RESULTS

Included in the study were 112 cats, representing 118 cases. Of the 118 cases, 98 (83%) and 20 (17%) received NE or O tubes, respectively. The most common underlying conditions were digestive (13.5%), hepatobiliary (11%) and upper urinary tract (11%) disorders. Hepatobiliary (50%) and upper respiratory tract (30%) conditions were predominant in the O tube group. Digestive (15%) and upper urinary tract (12%) diseases were more common in the NE tube group. Complications following tube placement occurred in 22/118 cases (18.6%). The global survival rate was 73% and did not differ between NE (71.4%) and O tube (80%) groups (P = 1.00) or disease categories (P = 0.61). Return of appetite before feeding tube removal occurred in 56 cases (47%), within a median of 3 days (range 1-30) and was not associated with mirtazapine administration (P = 1.00). Appetite returned earlier for cats with NE tubes (3 days, range 1-17) than for those with O tubes (33 days, range 5-60; P <0.05). Voluntary food intake was positively associated with survival (odds ratio 15.17). After discharge and feeding tube retrieval, return of appetite was observed in 67% of cases.

CONCLUSIONS AND RELEVANCE

Feeding tubes were predominantly placed for the management of appetite disturbance in cats with digestive, hepatobiliary and upper urinary tract diseases. While complications were frequent, they were mostly mild, easily managed and did not preclude feeding tube use. Return to appetite occurred in a large proportion of cats during or after assisted enteral feeding and was associated with survival.

2022 ISFM Consensus Guidelines on Management of the Inappetent Hospitalised Cat

PRACTICAL RELEVANCE

Inappetence may have many origins and, as a presenting sign or observation in the hospitalised patient, is common in feline practice. Nutritional assessment of every patient is encouraged, to identify the need for, and appropriate type of, intervention indicated. The impact of malnutrition may be significant on the feline patient, perpetuating illness, delaying recovery, slowing wound healing and negatively impacting gut health and immunity. Delayed intervention may result in the cat's deterioration; hence prompt control of contributing factors such as the underlying illness, pain, nausea, ileus and stress is vital to optimise voluntary food intake. Management is multimodal, comprising reduction of stress, medications and assisted nutrition in the form of tube feeding or parenteral nutrition. Use of antiemetic, analgesic, prokinetic and appetite stimulant medications may restore appetite, but placement of feeding tubes should not be delayed. Feeding tubes are generally well tolerated and allow provision of food, water and medication with minimal stress, although clinicians must be aware of complications such as stoma site infections and refeeding syndrome.

CLINICAL CHALLENGES

Cats are vulnerable to malnutrition owing to their unique metabolism and specific nutritional requirements. Moreover, their nature as a species means they are susceptible to stress in the hospital environment, which may result in reduced food intake; previous negative experiences may compound the problem. In particular, an inappropriate clinic environment and/or handling may cause or exacerbate inappetence in hospitalised patients, with negative impacts on recovery. Postponing interventions such as feeding tube placement to await improvement, owing to clinician or caregiver apprehension, may hinder recovery and worsen nutritional deficits.

EVIDENCE BASE

The 2022 ISFM Consensus Guidelines on Management of the Inappetent Hospitalised Cat have been created by a panel of experts brought together by the International Society of Feline Medicine (ISFM). Information is based on the available literature, expert opinion and the panel members' experience.

Amino Acids in the Nutrition, Metabolism, and Health of Domestic Cats

Domestic cats (carnivores) require high amounts of dietary amino acids (AAs) for normal growth, development, and reproduction. Amino acids had been traditionally categorised as nutritionally essential (EAAs) or nonessential (NEAAs), depending on whether they are synthesized de novo in the body. This review will focus on AA nutrition and metabolism in cats. Like other mammals, cats do not synthesize the carbon skeletons of twelve proteinogenic AAs: Arg, Cys, His, Ile, Leu, Lys, Met, Phe, Thr, Trp, Tyr, and Val. Like other feline carnivores but unlike many mammals, cats do not synthesize citrulline and have a very limited ability to produce taurine from Cys. Except for Leu and Lys that are strictly ketogenic AAs, most EAAs are both glucogenic and ketogenic AAs. All the EAAs (including taurine) must be provided in diets for cats. These animals are sensitive to dietary deficiencies of Arg and taurine, which rapidly result in life-threatening hyperammonemia and retinal damage, respectively. Although the National Research Council (NCR, Nutrient requirements of dogs and cats. National Academies Press, Washington, DC, 2006) does not recommend dietary requirements of cats for NEAAs, much attention should be directed to this critical issue of nutrition. Cats can synthesize de novo eight proteinogenic AAs: Ala, Asn, Asp, Gln, Glu, Gly, Pro, and Ser, as well as some nonproteinogenic AAs, such as γ-aminobutyrate, ornithine, and β-alanine with important physiological functions. Some of these AAs (e.g., Gln, Glu, Pro, and Gly) are crucial for intestinal integrity and health. Except for Gln, AAs in the arterial blood of cats may not be available to the mucosa of the small intestine. Plant-source foodstuffs lack taurine and generally contain inadequate Met and Cys and, therefore, should not be fed to cats in any age group. Besides meat, animal-source foodstuffs (including ruminant meat & bone meal, poultry by-product meal, porcine mucosal protein, and chicken visceral digest) are good sources of proteinogenic AAs and taurine for cats. Meeting dietary requirements for both EAAs and NEAAs in proper amounts and balances is crucial for improving the health, wellbeing, longevity, and reproduction of cats.

Appetite-stimulating effect of gabapentin vs mirtazapine in healthy cats post-ovariectomy

OBJECTIVES

The aim of the study was to evaluate the appetite-stimulating effect of gabapentin by comparing it with mirtazapine in healthy cats in the first 8 h after ovariectomy surgery.

METHODS

This double-masked, placebo-controlled, prospective clinical trial included 60 healthy cats presented to the hospital for ovariectomy: 20 received gabapentin, 21 received mirtazapine and 19 received a placebo immediately before and 6 h after surgery. Food was offered at 2, 4, 6 and 8 h post-ovariectomy. After each meal, food intake was measured. Data were analysed using repeated-measure ANOVA and a linear mixed-model analysis. Post-hoc Tukey's honest significant difference test was performed for multiple comparisons.

RESULTS

Food intake increased in both treatment groups vs placebo. No statistically significant difference was found between cats treated with gabapentin or mirtazapine.

CONCLUSIONS AND RELEVANCE

Cats receiving gabapentin ate more than cats in the placebo group. Thirty percent of cats in the gabapentin group covered their resting energy requirements, while none of the cats in the placebo group did. Gabapentin and mirtazapine produced similar effects on food intake.

Subhypnotic dose of intravenous propofol stimulates appetite in cats with stress-induced anorexia

BACKGROUND

Stress-induced anorexia is common in cats. While medications are available to stimulate appetite, many require oral administration, have delayed onset-of-action or cause adverse side effects. The aim of this study was to determine whether cats diagnosed with stress-induced anorexia given a subhypnotic dose of intravenous propofol would have increased short-term appetite as compared to those given placebo.

METHODS

Anorexic shelter cats received either 1 mg/kg propofol or 1 mL saline placebo and then presented with various commercial cat foods. Grams of food consumed was measured at 15 and 30 min, and total grams compared between treatment and control groups using the Wilcoxon rank-sum test. 12 cats were enrolled, with six cats randomly assigned to each group.

RESULTS

The median amount consumed by the treatment group was 31 g (range: 0-72), with the median for the four cats (67 per cent) who consumed food being 45 g (range: 26-72), or 49 per cent of their daily maintenance calorie requirement. The median amount consumed by control cats was 0 g (range: 0-5), with one cat consuming food. Total grams consumed was different between treatment and control groups (P=0.05).

CONCLUSION

A subhypnotic dose of intravenous propofol increased appetite in cats with stress-induced anorexia for a 30 min period.

Anorexia and the Cancer Patient

Appetite influences perceived quality of life for a dog or cat with cancer. Inappetence often is multifactorial, complicating treatment. Cancer-related anorexia/cachexia syndrome is a metabolic, paraneoplastic syndrome characterized by decreased food intake, involuntary weight loss, and loss of fat and muscle. If weight loss/cachexia has an impact on canine and feline cancer patients as in humans, management may improve survival times and quality of life. The challenge is having effective, proved therapies available for clinical use. Recent Food and Drug Administration approvals for appetite stimulation have renewed interest and discussion and has the potential to alter the course of case management.

Perspectives on Feeding and Nutrition

Many palliative care patients have reduced oral intake during their illness. Managing inadequate intake through appetite stimulation and/or artificial hydration and nutrition poses many clinical, ethical, and logistical dilemmas. This article aids the health care team in making appropriate recommendations regarding assisted nutrition and hydration for palliative care and terminal patients. It provides a decision-making framework, including an ethical approach to determining appropriate use of assisted feeding and hydration methods in pets at the end of life. It also summarizes various clinical and logistical approaches to treating decreased food/water consumption, including potential benefits and burdens, should intervention be deemed appropriate.

A double-blind, placebo-controlled, randomized study to evaluate the weight gain drug, mirtazapine transdermal ointment, in cats with unintended weight loss

Mirtazapine is classified as a weight gain drug in cats, and the purpose of this study was to evaluate its efficacy in cats experiencing unintended weight loss. This was a multi-center, double-blind, placebo-controlled, randomized clinical study in client-owned cats ≥1 year of age, weighing ≥2 kg, with a documented loss (≥5%) in body weight. Cats were treated once daily with either 2 mg/cat mirtazapine transdermal ointment (n = 83) or placebo (n = 94) (Per Protocol population) applied to the inner surface of the pinna for 14 ± 3 days. Physical examination, body weight, complete blood count, serum chemistry, and urinalysis were performed prior to treatment and on Day 14. Changes in body weight between the mirtazapine and placebo groups were evaluated from Day 1 to Day 14 and compared using a two-sample t test. The mean percent change in body weight was +3.9% (standard deviation ±5.4%) in the mirtazapine group and +0.4% (±3.3%) in the placebo group (p < 0.0001). The most common adverse event was mild erythema at the application site in 17.4% of placebo and 10.4% of mirtazapine-treated cats. Application of mirtazapine transdermal ointment was well tolerated both topically and systemically and resulted in significant weight gain in cats experiencing unintended weight loss associated with various underlying diseases.

Tools for Managing Feline Problem Behaviours Psychoactive medications

PRACTICAL RELEVANCE

When a cat is presented for evaluation of a problem behaviour, it is likely that the cat's wellbeing is negatively affected by the condition. In addition, the owners and any other animals around the cat may also be experiencing negative consequences. When managing these cases, it is important to consider all options (including behaviour modification, environmental changes, medications) that can help to reach an optimal solution. Medication cannot teach the cat how to behave or change a particular behaviour; it can, however, reduce arousal, excitability, reactivity and anxiety.

RATIONALE

The rationale for using psychoactive medications in behavioural medicine, or veterinary psychiatry, is to increase the wellbeing of the animal and to aid the owner and practitioner in managing problem behaviours. Medications should always be used as an adjunct to behavioural and environmental modification.

CLINICAL CHALLENGES

Many psychoactive medications cannot be used in the face of certain physical illnesses or concurrently with other medications. Some medications may also have side effects, not be effective at the recommended dose or have a paradoxical effect. Furthermore, success is reliant on the owner being able to administer the medication.

AIMS

This article aims to guide practitioners by discussing questions such as how to choose the appropriate medication, how to dose it and how long to use it. The psychoactive medications most commonly used in feline medicine are reviewed, as well as some that are newer or less common.

EVIDENCE BASE

Data for the use of medications in cats is limited, with just a small number of clinical-, species- and problem-directed studies available, and a few more case series and case reports. Where feline-specific research is not available, the authors have drawn upon research published in other species, such as humans, dogs and rats, as well as anecdotal reports and expert opinions.

In vivo and in vitro assessment of mirtazapine pharmacokinetics in cats with liver disease

Background

Liver disease (LD) prolongs mirtazapine half‐life in humans, but it is unknown if this occurs in cats with LD and healthy cats.

Hypothesis/Objectives

To determine pharmacokinetics of administered orally mirtazapine in vivo and in vitro (liver microsomes) in cats with LD and healthy cats.

Animals

Eleven LD and 11 age‐matched control cats.

Methods

Case‐control study. Serum was obtained 1 and 4 hours (22 cats) and 24 hours (14 cats) after oral administration of 1.88 mg mirtazapine. Mirtazapine concentrations were measured by liquid chromatography with tandem mass spectrometry. Drug exposure and half‐life were predicted using limited sampling modeling and estimated using noncompartmental methods. in vitro mirtazapine pharmacokinetics were assessed using liver microsomes from 3 LD cats and 4 cats without LD.

Results

There was a significant difference in time to maximum serum concentration between LD cats and control cats (median [range]: 4 [1‐4] hours versus 1 [1‐4] hours; P = .03). The calculated half‐life of LD cats was significantly prolonged compared to controls (median [range]: 13.8 [7.9‐61.4] hours versus 7.4 [6.7‐9.1] hours; P < .002). Mirtazapine half‐life was correlated with ALT (P = .002; r = .76), ALP (P < .0001; r = .89), and total bilirubin (P = .0008; r = .81). The rate of loss of mirtazapine was significantly different between microsomes of LD cats (–0.0022 min⁻¹, CI: −0.0050 to 0.00054 min⁻¹) and cats without LD (0.01849 min⁻¹, CI: −0.025 to −0.012 min⁻¹; P = .002).

Conclusions and Clinical Importance

Cats with LD might require less frequent administration of mirtazapine than normal cats.

Single and multiple dose pharmacokinetics of a novel mirtazapine transdermal ointment in cats

Single and multiple dose pharmacokinetics (PK) of mirtazapine transdermal ointment applied to the inner ear pinna of cats were assessed. Study 1 was a randomized, cross-over single dose study (n = 8). Cats were treated once with 0.5 mg/kg of mirtazapine transdermal ointment applied topically to the inner ear pinna (treatment) or administered orally (control) and then crossed over after washout. Plasma was collected predose and at specified intervals over 96 hr following dosing. Study 2 was a multiple dose study (n = 8). Cats were treated daily for 14 days with 0.5 mg/kg of mirtazapine transdermal ointment applied topically to the inner pinna. Plasma was collected on Day 13 predose and at specified intervals over 96 hr following the final dose. In Study 1, single transdermal administration of mirtazapine resulted in mean T_max = 15.9 hr, C_max = 21.5 ng/mL, AUC_0-24 = 100 ng*hr/mL, AUC_0-∞ = 260 ng*hr/mL and calculated half-life = 26.8 hr. Single oral administration of mirtazapine resulted in mean T_max = 1.1 hr, C_max = 83.1 ng/mL, AUC_0-24 = 377 ng*hr/mL, AUC_0-∞ = 434 ng*hr/mL and calculated half-life = 10.1 hr. Mean relative bioavailability (F) of transdermal to oral dosing was 64.9%. In Study 2, daily application of mirtazapine for 14 days resulted in mean T_max = 2.1 hr, C_max = 39.6 ng/mL, AUC_0-24 = 400 ng*hr/mL, AUC_0-∞ = 647 ng*hr/mL and calculated half-life = 20.7 hr. Single and repeat topical doses of a novel mirtazapine transdermal ointment achieve measurable plasma concentrations in cats.

Hepatic lipidosis: Clinical review drawn from collective effort

Practical relevance: Hepatic lipidosis (HL) is the most common form of liver dysfunction in cats. If recognized early and treated appropriately, the prognosis is good; if not, the prognosis is grave. Clinical challenges: Distinguishing HL as idiopathic or secondary is critical since the presence of a concurrent disease affects the therapeutic plan and the prognosis.

AUDIENCE

Despite the unique and severe nature of a cat's response to anorexia and the complexity of the metabolic changes underlying this condition, the clinical acumen and technical ability to effectively diagnose and treat HL are readily available to all small animal practitioners. Patient group: Although many species develop a 'fatty liver', the cat is one of relatively few species that suffer from HL. The classic presentation is that of an overweight cat that stops eating for days to weeks, losing weight in the process. Equipment: Abdominal ultrasound is frequently employed in the diagnostic work-up of an anorectic cat; ultrasonographic findings often support a presumptive diagnosis, provide samples for cytology and, perhaps most importantly, help identify concurrent conditions that must be addressed for therapeutic success. All of the equipment necessary for essential nutritional intervention in an anorectic cat is readily available and easily affordable. Evidence base: The material for this review draws heavily on a relatively large number of original studies, excellent reviews by recognized experts, and informative communication with experienced clinicians, hence the term 'collective effort'.

Capromorelin: a ghrelin receptor agonist and novel therapy for stimulation of appetite in dogs

Ghrelin is a hormone, secreted from cells in the stomach, which is important in the regulation of appetite and food intake in mammals. It exerts its action by binding to a specific G-protein-coupled receptor, the growth hormone secretagogue receptor 1a (GHS-R1a) which is found in areas of the brain associated with the regulation of food intake. Ghrelin causes a release of growth hormone (GH) through binding to GHS-R1a in the hypothalamus and pituitary gland. A class of compounds known as growth hormone secretagogues, or ghrelin receptor agonists, were developed for therapeutic use in humans for the stimulation of GH in the frail elderly, and have subsequently been studied for their effects on increasing appetite and food intake, increasing body weight, building lean muscle mass, and treating cachexia. Subsequent research has shown that ghrelin has anti-inflammatory and immunomodulatory effects. This article reviews the basic physiology of ghrelin and the ghrelin receptor agonists, including the available evidence of these effects in vitro and in vivo in rodent models, humans, dogs and cats. One of these compounds, capromorelin, has been FDA-approved for the stimulation of appetite in dogs (ENTYCE ®). The data available on the safety and effectiveness of capromorelin is reviewed, along with a discussion of the potential clinical applications for ghrelin receptor agonists in both human and veterinary medicine.

Mirtazapine toxicity in cats: retrospective study of 84 cases (2006-2011)

Objectives Mirtazapine is commonly used in veterinary medicine at doses of 1.88 or 3.75 mg as an appetite stimulant. The objectives of this study were to determine the most common adverse effects reported and the dose associated with these signs. Methods Records of cats with mirtazapine exposure (2006-2011) were obtained from the American Society for the Prevention of Cruelty to Animals' Animal Poison Control Center. The following parameters were recorded: signalment, weight, outcome, agent ingested, amount ingested, route of exposure, clinical signs observed, intended of use, onset time of signs and duration of signs. Results The 10 most commonly observed adverse effects reported in 84 cats exposed to mirtazapine included vocalization (56.0% of cats; mean dose 2.56 mg/kg), agitation (31.0%; 2.57 mg/kg), vomiting (26.2%; 2.92 mg/kg), abnormal gait/ataxia (16.7%; 2.87 mg/kg), restlessness (14.3%; 3.55 mg/kg), tremors/trembling (14.3%; 2.43 mg/kg), hypersalivation (13.0%; 2.89 mg/kg), tachypnea (11.9%; 3.28 mg/kg), tachycardia (10.7%; 3.04 mg/kg) and lethargy (10.7%; 2.69 mg/kg). Fifty-nine (70.2%) cases were considered accidental ingestions and 25 (29.8%) cases were given mirtazapine as prescribed. The doses associated with signs of toxicity were 15.00 mg (40 cats), 3.75 mg (25 cats), 7.50 mg (four cats), 30.00 mg (one cat), 18.75 mg (one cat), 11.25 mg (one cat), 5.80 mg (one cat) and 1.88 mg (one cat). For cats with available information, the onset of clinical signs ranged from 15 mins to 3 h, and time to resolution of clinical signs ranged from 12-48 h. Conclusions and relevance The greater number of adverse effects at 3.75 mg rather than 1.88 mg suggests that the latter may be a more appropriate starting dose for stimulating appetite while limiting toxicity. The benefit of dispensing exact doses of mirtazapine is implied given the likelihood of accidental administration of a full tablet (15 mg) and the resulting toxicity.

Update in feline therapeutics: clinical use of 10 emerging therapies

PRACTICAL RELEVANCE

The field of veterinary medicine is constantly evolving. New medications are being introduced into clinical practice, and novel uses for established medications are frequently being discovered as new information comes to light.

CLINICAL CHALLENGES

Therapeutic options for our feline patients can be restricted based on inadequate clinical evidence, adverse effects and patient compliance concerns. Additionally, with the reduced availability of commonly used medications in some regions, clinicians are forced to utilize alternatives with which they may have limited experience.

AUDIENCE

This review article is directed towards primary care veterinarians working with feline patients. The selection of medications discussed is based on many of the clinical challenges commonly encountered in practice.

EVIDENCE BASE

The evidence for use of some of these medications is limited due to their novelty. Known mechanisms of action, pharmacokinetic and pharmacodynamics data, adverse effects and clinical uses are reviewed where possible, with clinical recommendations made based on the evidence of data available.