Safety and tolerability of long-term treatment with darolutamide in patients with metastatic castration-resistant prostate cancer.

BACKGROUND: In patients with metastatic castration-resistant prostate cancer, darolutamide was well tolerated for 25 months, but minimal long-term safety data are available. METHODS: Treatment-emergent adverse events (TEAEs) for patients receiving darolutamide for a median of 38 months (n = 13) are described in this pooled analysis of individual patient data from phase 1/2 studies. RESULTS: All patients reported TEAEs (mostly grade 1/2). The most common TEAEs were diarrhea, abdominal pain, and nausea. Serious TEAEs were reported in six patients (none related to darolutamide). All treatment-related TEAEs (n = 5) were grade 1. CONCLUSIONS: Long-term darolutamide treatment was well tolerated; no new safety signals observed. In patients with mCRPC, long-term darolutamide treatment was well tolerated and no new safety signals were observed. These findings are consistent with previous reports, demonstrating a favorable safety and tolerability profile of darolutamide.

Pregabalin Alleviates Anxiety and Fear in Cats during Transportation and Veterinary Visits-A Clinical Field Study.

Cats frequently suffer from anxiety related to travel and veterinary visits. One sequela is avoidance of veterinary visits and lack of adequate veterinary care. The objective of this study was to test clinical efficacy and safety of a novel formulation of a pregabalin 50 mg/mL oral solution for alleviation of anxiety and fear in cats during transport and veterinary visits. A total of 209 client-owned cats were given either a flavored pregabalin oral solution at the dosage of 5 mg/kg (n = 108) or an identical placebo (n = 101) approximately 90 min before placing them into the carrier and transporting them in a car for at least 20 min to a veterinary clinic. The treatment effect using a 5-point numerical rating scale was evaluated during transportation by the owner and during clinical examination by the veterinarian, both blinded to the treatment. In addition, to verify the owner assessment, an external expert blinded to the treatment and owner assessment evaluated the transportation video recordings using the same rating scale as the owner. Pregabalin 5 mg/kg statistically significantly decreased both travel- (p < 0.01) and veterinary-visit- (p < 0.01) related anxiety compared to the placebo. The external expert's evaluation was in agreement with the owners' assessment confirming the treatment effect during transportation (p < 0.01). Treatment was well tolerated with only a few cats showing transient slight incoordination and tiredness. The flavored oral solution formulation with a small dosing volume of 0.1 mL/kg was found by the owners to be user-friendly and was well-accepted by the cats. This study demonstrated that a single oral dosage of the novel pregabalin oral solution alleviates anxiety and fear related to transportation and veterinary visits in cats, thus providing practical aid for both owners and veterinarians to enable cat-friendly handling and improving the welfare of cats in situations they often perceive as very stressful.

Nanoparticle-based oral formulation can surprise you with inferior in vivo absorption in humans.

Particle size reduction leads to an increase in the drug dissolution rate, which in turn can lead to a substantial increase in the bioavailability of a poorly soluble compound. To improve bioavailability, a practically insoluble investigational drug, ODM-106, was nanomilled and capsule formulations with three different drug amounts were prepared for the first-in-man study. Fast in vitro dissolution was achieved from all the capsules containing different amounts of drug nanoparticles but in the clinical study, surprisingly, low bioavailability was observed from the highest capsule strength (100 mg) in comparison to a lower strength (10 mg). In order to study further the discrepant in vitro-in vivo correlation (IVIVC), a discriminative dissolution method was developed. It was noticed that the degree of supersaturation increased significantly as the stabilizers' concentration within the dried nanoformulations was increased. Hypromellose provided a physical barrier between nanoparticles to prevent aggregation during drying. SLS on the other hand improved wettability and provided supersaturation. The drug load, nanoparticle/polymer/surfactant/filler ratios and selected drying step were discovered to be critical to the nanoformulations' performance. Aggregation of nanoparticles, in the absence of optimal stabilizer concentration, compromised dissolution due to decreased surface area. In conclusion, the early development of a discriminative dissolution method and cautious selection of the nanoparticle/polymer ratio before manufacturing clinical batches is recommended.

Tasipimidine-the pharmacological profile of a novel orally active selective α2A-adrenoceptor agonist.

The pharmacological profile of tasipimidine, a novel orally active α2-adrenoceptor agonist developed for situational anxiety and fear in dogs, was studied in various in vitro and in vivo models. In the cell assays, tasipimidine demonstrated binding affinity and full agonism on the human α2A-adrenoceptors with a pEC50 of 7.57, while agonism on the α2B-and α2C-adrenoceptors and the rodent α2D-adrenoceptor was weaker, resulting in pEC50 values of 6.00, 6.29 and 6.56, respectively. Tasipimidine had a low binding affinity on the human α1-adrenoceptors. It had no functional effects in the LNCaP cells expressing endogenously the human α1A-adrenoceptors but was a weak agonist in the Chem-1 cells coexpressing Gα15 protein and α1A-adrenoceptors. In the recombinant CHO cells, although tasipimidine was a weak partial agonist in the inositol monophosphate accumulation assay, it was a full agonist in the intracellular [Ca2+] assay. No functional effects were observed on the human α1B-adrenoceptor, whereas in the rat α1A and α1B-adrenoceptors, tasipimidine was a weak partial agonist. In the rat vas deferens preparations, tasipimidine was a full agonist on the α2D-adrenoceptor but weak partial agonist on the α1-adrenoceptor. The receptor profile of tasipimidine indicated few secondary targets, and no functional effects were observed. Sedative effects of tasipimidine were demonstrated in vivo by the reduced acoustic startle reflex in rats with subcutaneous doses and decreased spontaneous locomotor activity in mice with subcutaneous and higher oral doses. It may be concluded that tasipimidine is an orally active and selective α2A-adrenoceptor agonist.

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.

Dexmedetomidine oromucosal gel reduces fear and anxiety in dogs during veterinary visits: A randomised, double-blind, placebo-controlled clinical pilot study.

INTRODUCTION: Many dogs are anxious and/or fearful in veterinary clinics and exhibit avoidant and/or defensive behaviour. The purpose of pharmacological interventions is to reduce anxiety and to enable patient-friendly, low stress physical examination and procedures. MATERIALS AND METHODS: This was a randomised, double-blind, placebo-controlled, parallel-group, multicentre, clinical-field study. The eligible dogs (n = 76) were randomly assigned to receive dexmedetomidine 0.1 mg/g oromucosal gel at a dose of 125 µg/m2 (n = 27) or 250 µg/m2 (n = 24), or an equivalent volume of placebo gel (n = 23). RESULTS: The investigator's ability to perform the intended procedure (physical examination and 1 short minor veterinary or husbandry procedure) was excellent for 40.7% of the dogs that received dexmedetomidine 125 µg/m2 and 33.3% of those that received dexmedetomidine 250 µg/m2 compared to only 4.3% of the placebo dogs. The overall treatment effect was statistically significant (p = 0.03). In addition, the investigators subjective stress level assessments revealed that dexmedetomidine treated dogs showed significantly more commonly relaxed body posture (p < 0.01) and more relaxed behaviour when entering the examination room (p = 0.02). There were very few adverse events, and treated animals were not sedated. CONCLUSIONS: This study indicated a beneficial treatment effect of dexmedetomidine gel in alleviation of canine fear and anxiety during minor veterinary or husbandry procedures in the clinic environment in dogs previously reported to suffer from fear and anxiety during veterinary visits. Both dexmedetomidine gel doses studied were effective, and no clinical safety concerns were noticed for either dose.

Use of Detomidine Oromucosal Gel for Alleviation of Acute Anxiety and Fear in Horses: A Pilot Study.

The aim of this randomized, double-blind, placebo-controlled, parallel group clinical field study was to evaluate the effect of detomidine oromucosal gel in alleviating anxiety and fear in horses. Sixteen horses with a history of acute anxiety and fear associated with firework-related noise entered the study. On New Year's Eve, eight horses were treated with 30 µg/kg detomidine gel and eight horses with placebo gel. When fireworks were present, 75% (6/8) of the detomidine-treated horses were scored by their owners as having a good or excellent treatment effect on anxiety and fear, while 50% (3/6) of horses receiving placebo were scored to have a good effect. Horses' behavior was video-recorded and assessed with a focal animal continuous method by a treatment-blind expert observer. Results showed that when fireworks were present, walking behavior decreased significantly (p < 0.05) after treatment with detomidine and that horses of the placebo group, overall, showed more restlessness, vocalization, and signs of colic (Wilcoxon matched-pairs test on the first PC, p = 0.007). This study indicates that detomidine oromucosal gel can be used to alleviate acute noise-related anxiety and fear in horses, but larger treatment groups are needed to confirm the results.

First-in-human Phase 1 open label study of the BET inhibitor ODM-207 in patients with selected solid tumours.

BACKGROUND: Bromodomain and extra-terminal domain (BET) proteins are reported to be epigenetic anti-cancer drug targets. This first-in-human study evaluated the safety, pharmacokinetics and preliminary anti-tumour activity of the BET inhibitor ODM-207 in patients with selected solid tumours. METHODS: This was an open-label Phase 1 study comprised of a dose escalation part, and evaluation of the effect of food on pharmacokinetics. ODM-207 was administered orally once daily. The dose escalation part was initiated with a dose titration in the initial cohort, followed by a 3 + 3 design. RESULTS: Thirty-five patients were treated with ODM-207, of whom 12 (34%) had castrate-resistant prostate cancer. One dose-limiting toxicity of intolerable fatigue was observed. The highest studied dose achieved was 2 mg/kg due to cumulative toxicity observed beyond the dose-limiting toxicity (DLT) treatment window. Common AEs included thrombocytopenia, asthenia, nausea, anorexia, diarrhoea, fatigue, and vomiting. Platelet count decreased proportionally to exposure with rapid recovery upon treatment discontinuation. No partial or complete responses were observed. CONCLUSIONS: ODM-207 shows increasing exposure in dose escalation and was safe at doses up to 2 mg/kg but had a narrow therapeutic window. CLINICAL TRIAL REGISTRATION: The clinical trial registration number is NCT03035591.

Safety and Antitumour Activity of ODM-201 (BAY-1841788) in Chemotherapy-naïve and CYP17 Inhibitor-naïve Patients: Follow-up from the ARADES and ARAFOR Trials.

BACKGROUND: ODM-201, a new androgen receptor antagonist for treatment of metastatic castration-resistant prostate cancer (mCRPC), demonstrated antitumour activity and acceptable tolerability in phase 1/2 trials. OBJECTIVE: To determine the antitumour activity and safety profile of extended treatment with ODM-201 in men with mCRPC. DESIGN, SETTING, AND PARTICIPANTS: ARADES and ARAFOR trials with ODM-201 enrolled chemotherapy-naïve and CYP17 inhibitor (CYP17i)-naïve mCRPC patients. Both trials had extended follow-up. Here we report results for chemotherapy-naïve and CYP17i-naïve patients from both trials (data cutoff October 2014 for ARADES and April 2015 for ARAFOR) after extended follow-up. INTERVENTION: A total of 41 chemotherapy-naïve and CYP17i-naïve patients received oral ODM-201 twice daily (total daily dose of 1200, 1400 or 1800mg). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Antitumour activity was assessed in terms of prostate-specific antigen (PSA) declines and PSA/radiographic progression. Safety was assessed until disease progression and/or drug discontinuation due to any intolerable adverse event (AE). RESULTS AND LIMITATIONS: ODM-201 safety data after a median treatment time of 13.5 mo (95% confidence interval [CI] 9.7-15.6, interquartile range [IQR] 7.5-22.0) were similar to those reported in the main ARADES and ARAFOR trials. The overall AE incidence was 80.5% (n=33/41), with 58.5% (n=24/41) of patients experiencing only grade 1-2 AEs. The most common AEs were fatigue, back pain, diarrhoea, nausea, and pain in extremity. The median times to PSA and radiological progression were 12.4 mo (95% CI 6.3-18.2, IQR 5.5-22.0) and 15.3 mo (95% CI 9.5-not reached [NR], IQR 6.3-NR), respectively. CONCLUSIONS: Extended treatment with ODM-201 (1200-1800mg/d) was well tolerated, with no new safety concerns, and provided evidence of sustained antitumour activity in chemotherapy-naïve and CYP17i-naïve patients with mCRPC. PATIENT SUMMARY: Prolonged treatment with high doses of ODM-201 was well tolerated and provided long-lasting disease control in patients with mCRPC. ODM-201 represents a therapeutic treatment option for mCRPC. The ARAFOR trial (including the follow-up stage) and the follow-up component of the ARADES trial are registered with ClinicalTrials.gov as trial numbers NCT01784757 and NCT01429064.

Safety and Antitumour Activity of ODM-201 (BAY-1841788) in Castration-resistant, CYP17 Inhibitor-naïve Prostate Cancer: Results from Extended Follow-up of the ARADES Trial.

BACKGROUND: Patients with castration-resistant prostate cancer (CRPC) had extended responses to the androgen receptor antagonist ODM-201, in phase 1/2 studies. OBJECTIVE: To evaluate the safety and antitumour activity of prolonged ODM-201 treatment in patients with CRPC. DESIGN, SETTING, AND PARTICIPANTS: The ARADES trial was a multicentre phase 1 (dose escalation) and phase 2 (dose expansion) trial; 134 patients with CRPC were stratified by previous chemotherapy to receive ODM-201. This paper reports extended follow-up in CYP17 inhibitor (CYP17i)-naïve patients. INTERVENTION: Patients (n=77) received oral ODM-201 twice daily at daily doses of 200-1800mg. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Safety, measured as the occurrence of adverse events (AEs), prostate-specific antigen (PSA), and radiographic progression. RESULTS AND LIMITATIONS: The safety profile of extended ODM-201 treatment (median treatment duration 8.2 mo, 95% confidence interval [CI] 5.6-11.0) was consistent with that reported at the time of the original data cutoff in the main ARADES trial, with no unexpected safety concerns over time. The majority of AEs (61.1%) were mild (grade 1); the most common AE was fatigue/asthenia (35.1% of patients), with no clear relationship to ODM-201. Median time to PSA progression was 25.2 mo (95% CI 11.3-25.2) for chemotherapy-naïve men and not reached (NR; 95% CI 5.5-NR) for chemotherapy-pretreated patients; a trend for improved antitumour response was observed for chemotherapy-naïve patients. The median time to radiographic progression was longer for chemotherapy-naïve (14.0 mo, 95% CI 8.1-33.3) than for chemotherapy-pretreated (7.2 mo, 95% CI 2.7-11.0) patients. CONCLUSIONS: Prolonged exposure to ODM-201 was well tolerated, with no additional safety concerns; disease suppression was sustained, especially in chemotherapy-naïve patients. These data support further development of ODM-201 in men with CYP17i-naïve CRPC. PATIENT SUMMARY: Extended ODM-201 therapy was well tolerated, with beneficial antitumour activity in men with advanced prostate cancer, indicating that ODM-201 may represent a new active treatment for men with CRPC. This extension trial is registered at ClinicalTrials.gov (www.clinicaltrials.gov) under identification number NCT01429064.

Bone Scan Index and Progression-free Survival Data for Progressive Metastatic Castration-resistant Prostate Cancer Patients Who Received ODM-201 in the ARADES Multicentre Study.

BACKGROUND: ODM-201, a new-generation androgen receptor inhibitor, has shown clinical efficacy in prostate cancer (PCa). Quantitative methods are needed to accurately assess changes in bone as a measurement of treatment response. The Bone Scan Index (BSI) reflects the percentage of skeletal mass a given tumour affects. OBJECTIVE: To evaluate the predictive value of the BSI in metastatic castration-resistant PCa (mCRPC) patients undergoing treatment with ODM-201. DESIGN, SETTING, AND PARTICIPANTS: From a total of 134 mCRPC patients who participated in the Activity and Safety of ODM-201 in Patients with Progressive Metastatic Castration-resistant Prostate Cancer clinical trial and received ODM-201, we retrospectively selected all those patients who had bone scan image data of sufficient quality to allow for both baseline and 12-wk follow-up BSI-assessments (n=47). We used the automated EXINI bone BSI software (EXINI Diagnostics AB, Lund, Sweden) to obtain BSI data. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used the Cox proportional hazards model and Kaplan-Meier estimates to investigate the association among BSI, traditional clinical parameters, disease progression, and radiographic progression-free survival (rPFS). RESULTS AND LIMITATIONS: In the BSI assessments, at follow-up, patients who had a decrease or at most a 20% increase from BSI baseline had a significantly longer time to progression in bone (median not reached vs 23 wk, hazard ratio [HR]: 0.20; 95% confidence interval [CI], 0.07-0.58; p=0.003) and rPFS (median: 50 wk vs 14 wk; HR: 0.35; 95% CI, 0.17-0.74; p=0.006) than those who had a BSI increase >20% during treatment. CONCLUSIONS: The on-treatment change in BSI was significantly associated with rPFS in mCRPC patients, and an increase >20% in BSI predicted reduced rPFS. BSI for quantification of bone metastases may be a valuable complementary method for evaluation of treatment response in mCRPC patients. PATIENT SUMMARY: An increase in Bone Scan Index (BSI) was associated with shorter time to disease progression in patients treated with ODM-201. BSI may be a valuable method of complementing treatment response evaluation in patients with advanced prostate cancer.

Activity and safety of ODM-201 in patients with progressive metastatic castration-resistant prostate cancer (ARADES): an open-label phase 1 dose-escalation and randomised phase 2 dose expansion trial.

BACKGROUND: ODM-201 is a novel androgen receptor (AR) inhibitor designed to block the growth of prostate cancer cells through high-affinity binding to the AR and inhibition of AR nuclear translocation. This trial assessed ODM-201's safety, pharmacokinetics, and activity in men with metastatic castration-resistant prostate cancer. METHODS: The ARADES trial is an open-label phase 1-2 trial undertaken in 23 hospitals across Europe and USA with ongoing long-term follow-up. Men with progressive metastatic castration-resistant prostate cancer, who had castrate concentrations of testosterone and an Eastern Cooperative Oncology Group score of 0-1 were enrolled. In the phase 1 part of the trial, patients were given oral ODM-201 at a starting daily dose of 200 mg, which was increased to 400 mg, 600 mg, 1000 mg, 1400 mg, and 1800 mg. In phase 2, patients were randomly assigned centrally and stratified by previous chemotherapy and treatment with CPY17 inhibitors, to receive one of three daily doses of ODM-201 (200 mg, 400 mg, and 1400 mg). The primary endpoint in phase 1 was safety and tolerability, whereas in phase 2 it was the proportion of patients with a PSA response (50% or greater decrease in serum PSA) at week 12. All analyses included patients who had received at least one dose of ODM-201. This trial is registered with ClinicalTrials.gov, number NCT01317641, and NCT01429064 for the follow-up after 12 weeks. FINDINGS: We enrolled patients between April 5, 2011, and March 12, 2013. In phase 1, 24 patients were enrolled to six sequential cohorts of three to six patients and received a daily dose of ODM-201, 200-1800 mg. No dose-limiting toxic effects were reported and the maximum tolerated dose was not reached. In phase 1, three patients reported eight adverse events of grade 3 (fracture, muscle injury, laceration, paralytic ileus, pain, presyncope, urinary retention, and vomiting) and one patient had a grade 4 adverse event (lymphoedema). None of the grade 3-4 adverse events were deemed to be related to ODM-201. Of the phase 1 patients, the four who received 200 mg, seven who received 400 mg, and three who received 1400 mg entered the phase 2 part of the trial. In addition to these patients, 110 were randomly assigned to three groups: 200 mg (n=38), 400 mg (n=37), and 1400 mg (n=35). For these patients, the most common treatment-emergent adverse events were fatigue or asthenia (15 [12%] of 124 patients), hot flush (six [5%]), and decreased appetite (five [4%]). One patient (<1%) had a grade 3 treatment-emergent adverse event (fatigue); no patients had a treatment-emergent grade 4 adverse event. 38 patients who received 200 mg, 39 who received 400 mg, and 33 who received 1400 mg were assessable for PSA response at 12 weeks. 11 (29%) patients in the 200 mg group, 13 (33%) in the 400 mg group, and 11 (33%) in the 1400 mg group had a PSA response at 12 weeks. INTERPRETATION: Our results suggest that ODM-201 monotherapy in men with progressive metastatic castration-resistant prostate cancer provides disease suppression and that ODM-201 has a favourable safety profile. These findings support further investigation of clinical responses with ODM-201 in men with castration-resistant prostate cancer. FUNDING: Orion Corporation Orion Pharma, Endo Pharmaceuticals Inc.

Clinical evaluation of the efficacy and safety of a constant rate infusion of dexmedetomidine for postoperative pain management in dogs.

OBJECTIVE: To compare postoperative analgesia provided by a constant rate infusion (CRI) of dexmedetomidine (DMED) to that of a well-established positive control [morphine (MOR)] in critically ill dogs. The sedative, cardiorespiratory effects and clinical safety of a 24-hour DMED CRI were also evaluated. STUDY DESIGN: Prospective, randomised, blinded, positive-controlled parallel-group clinical study. ANIMALS: Forty hospitalised, client-owned dogs requiring post-operative pain management after invasive surgery. METHODS: After surgery, a loading dose of either DMED (25 microg m(-2)) or MOR (2500 microg m(-2)) followed by a 24-hour CRI of DMED (25 microg m(-2) hour(-1)) or MOR (2500 microg m(-2) hour(-1)) was administered. Pain was measured using the Short Form of the Glasgow Composite Measure Pain Scale, sedation and physiological variables were scored at regular intervals. Animals considered to be painful received rescue analgesia and were allocated to a post-rescue protocol; animals which were unresponsive to rescue analgesia were removed from the study. Data were analysed with anova, two-sample t-tests or Chi-square tests. Time to intervention was analysed with Kaplan-Meier methodology. RESULTS: Forty dogs were enrolled. Twenty dogs (9 DMED and 11 MOR) did not require rescue analgesia. Eleven DMED and eight MOR dogs were allocated to the post-rescue protocol and seven of these removed from the study. Significant differences in pain scores between groups were not observed during the first 12 hours, however, DMED dogs were less (p = 0.009) painful during the last 12 hours. Sedation score over the entire 24-hour study was not significantly different between groups. CONCLUSION / CLINICAL RELEVANCE: Dexmedetomidine CRI was equally effective as MOR CRI at providing postoperative analgesia and no clinically significant adverse reactions were noted. This study shows the potential of DMED to contribute to a balanced postoperative analgesia regimen in dogs.

Dexmedetomidine constant rate infusion for 24 hours during and after propofol or isoflurane anaesthesia in dogs.

OBJECTIVE: To evaluate cardiovascular and respiratory effects and pharmacokinetics of a 24-hour intravenous constant rate infusion (CRI) of dexmedetomidine (DMED) during and after propofol (PRO) or isoflurane (ISO) anaesthesia in dogs. STUDY DESIGN: Prospective, randomized, cross-over study. ANIMALS: Ten healthy adult Beagles. METHODS: Instrumented dogs received a DMED-loading bolus (25 microg m(-2)) at time 0 followed by a 24-hour CRI (25 microg m(-2) hour(-1)), with PRO or ISO induction/maintenance of anaesthesia during the first 2 hours (PRO and ISO treatment groups, respectively). Cardiovascular, respiratory, blood gas, airway gas, serum chemistry variables and DMED plasma concentration data were collected at -15, 5, 15, 30, 45, 60, 90 and 120 minutes. A number of cardiorespiratory and tissue oxygenation variables were calculated from the above data. After the 2-hours of anaesthesia, heart and respiratory rates and electrocardiograms were recorded and DMED plasma concentrations were determined for up to 26 hours. RESULTS: Vasopressor effects and the decrease in heart rate (HR) and cardiac index induced by DMED were greater for PRO than ISO, but were within clinically acceptable ranges. Adequate oxygenation was maintained above the critical O(2) delivery level. The overall incidence of unfavourable arrhythmias was low and tended to vary inversely with HR. Mean DMED plasma concentration ranged from 0.23 to 0.47 ng mL(-1) for both groups during the 24-hour CRI with a mean elimination half-life of approximately 0.46 hour. CONCLUSION AND/CLINICAL RELEVANCE: DMED CRI resulted in typical alpha(2)-agonist induced haemodynamic changes with minimal respiratory effects, and appeared to be an efficacious adjunct during and after PRO or ISO anaesthesia in healthy dogs.

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.