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Dose regimens1
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Adverse effects113
In the field study safety evaluation, 110 dogs received Zenalpha and 113 dogs received dexmedetomidine (control group) for sedation. Dogs ranged in age from 5 months to 14.5 years, weighed 5.1 to 154 lbs, and represented purebreds and breed mixes. Table 2. Adverse reactions during the field study Adverse Reaction Zenalpha(N = 110)n (%) Dexmedetomidine(N = 113)n (%) Diarrhea 4 (3.6) 0 (0) Muscle tremor 2 (1.8) 0 (0) Signs of colitis 2 (1.8) 0 (0) Hypothermia that necessitated use of an external heat source Hypothermia 1 (0.9) 13 (11.5) Vomiting 1 (0.9) 6 (5.3) Involuntary defecation 1 (0.9) 0 (0) Nausea 1 (0.9) 0 (0) Tachycardia, transient 1 (0.9) 0 (0) Prolonged sedation 0 (0) 3 (2.7) Urinary incontinence 0 (0) 2 (1.8) Retching 0 (0) 1 (0.9) Apnea 0 (0) 1 (0.9) Bradycardia 0 (0) 1 (0.9) Hyperthermia 0 (0) 1 (0.9)
Species not recordedOn-label (ON_LABEL)United States1 source record · View provenance
- Species not recorded · SPL section 34084-4 (ADVERSE REACTIONS SECTION) · United States · On-label (ON_LABEL) · Pending clinical review (PROPOSED) · Rule-based
These are counts of spontaneously reported events, not proven adverse effects, causal relationships, or incidence rates.
Bars compare report counts within each species; they do not show incidence.
More reportsFewer reportsDog
- Lack of efficacy - NOS275 reports
- Diarrhoea52 reports
- Sedation prolonged35 reports
- Bradycardia25 reports
- Partial lack of efficacy21 reports
- Vomiting21 reports
- Tachycardia19 reports
- Death18 reports
- Hypotension17 reports
- Involuntary defecation16 reports
- Vocalisation15 reports
- Immediate pain upon injection14 reports
Cat
- Abnormal radiograph finding1 reports
- Bumping into walls1 reports
- Hypertension1 reports
- Nasal discharge1 reports
- Not eating1 reports
- Not himself/herself1 reports
- Oral cavity disorder NOS1 reports
- Pulmonary disorder NOS1 reports
- Respiratory distress1 reports
- Tachycardia1 reports
- Tachypnoea1 reports
- Vomiting1 reports
Contraindications1
Do not use Zenalpha in dogs with cardiac disease, respiratory disorders, shock, severe debilitation, that have hypoglycemia or are at risk of developing hypoglycemia, or are stressed due to extreme heat, cold or fatigue. Zenalpha is contraindicated in dogs with a known sensitivity to medetomidine or vatinoxan.
Species not recordedOn-label (ON_LABEL)United States1 source record · View provenance
- Species not recorded · SPL section 34070-3 (CONTRAINDICATIONS SECTION) · United States · On-label (ON_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Precautions2
Federal law restricts this drug to use by or on the order of a licensed veterinarian.
Species not recordedOn-label (ON_LABEL)United States1 source record · View provenance
- Species not recorded · SPL section 34071-1 (WARNINGS SECTION) · United States · On-label (ON_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dogs should be monitored frequently during sedation for changes in heart rate, blood pressure, respiratory rate and body temperature. Tachycardia may occur in some dogs after recovery from sedation. In the event of hypoxia or apnea, supplemental oxygen should be administered. Following administration of Zenalpha, a decrease in body temperature may occur and an external heat source may be needed to maintain body temperature. Hypothermia may persist longer than sedation and analgesia. Effectiveness The analgesic effect of Zenalpha will not last longer than the sedative effects. Additional analgesic(s) should be administered as needed (see). Nervous, excited or agitated dogs with high levels of endogenous catecholamines may exhibit a reduced pharmacological response to Zenalpha (ineffectiveness). The onset of sedative/analgesic effects could be slowed, or the depth and duration of effects could be diminished or nonexistent. Therefore, allow the dog to rest quietly for 10 to 15 minutes after injection. 2 With the alpha-adrenoceptor agonist drug class, including Zenalpha, the potential for isolated cases of hypersensitivity, including paradoxical response (excitation) exists. Repeat dosing with Zenalpha has not been evaluated. Zenalpha has only been evaluated in fasted dogs; therefore, the effects on fed dogs (for example occurrence of vomiting) has not been characterized. The concurrent use of anticholinergic medications and Zenalpha has not been evaluated. Animal Safety Zenalpha may decrease serum glucose in healthy dogs and this effect may persist longer than sedation (see). The safe use of Zenalpha in dogs with hepatic or renal impairment has not been evaluated. The safe use of Zenalpha has not been evaluated in dogs younger than 4.5 months old. The safe use of Zenalpha has not been evaluated in dogs that are pregnant, lactating, or intended for breeding.
Species not recordedOn-label (ON_LABEL)United States1 source record · View provenance
- Species not recorded · SPL section 42232-9 (PRECAUTIONS SECTION) · United States · On-label (ON_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics1
2 2 2 Medetomidine is a potent non-narcotic alpha-adrenoceptor agonist which produces sedation and analgesia. These effects are dose dependent in depth and duration. Medetomidine is a racemic mixture containing the active enantiomer dexmedetomidine. Within the central nervous system, sympathetic neurotransmission is inhibited and the level of consciousness decreases. Respiratory rate and body temperature can also decrease. In the peripheral vasculature, medetomidine stimulates alpha-adrenoceptors within vascular smooth muscle which induces vasoconstriction and hypertension which consequently decreases the heart rate and cardiac output. Dexmedetomidine also induces a number of other alpha-adrenoceptor mediated effects, which include piloerection, depression of motor and secretory functions of the gastrointestinal tract, diuresis and hyperglycemia. 2 2 Vatinoxan is a peripherally selective alpha-adrenoceptor antagonist which lacks activity in the central nervous system. By limiting its effects to peripheral organ systems, vatinoxan will prevent or attenuate the cardiovascular and other effects of dexmedetomidine outside the central nervous system when administered simultaneously with the alpha-adrenoceptor agonist. The central effects of dexmedetomidine remain unaltered, although vatinoxan will reduce the duration of sedation and analgesia induced by dexmedetomidine, predominantly by increasing the clearance of the latter via improving the cardiovascular function. 2 2 2 2 No pharmacokinetic assessment was performed on Zenalpha [medetomidine (1 mg/m) + vatinoxan (20 mg/m)]. However, after IM administration of a pilot formulation of medetomidine (1 mg/m) + vatinoxan (30 mg/m), both medetomidine and vatinoxan were rapidly and highly absorbed from the injection site. Maximal plasma concentration was reached at 12.6 ± 4.7 (mean ± standard deviation) minutes and 17.5 ± 7.4 minutes for dexmedetomidine (the active enantiomer of medetomidine) and vatinoxan, respectively. Vatinoxan increased the volume of distribution and the clearance of dexmedetomidine. Thus, the clearance of dexmedetomidine was increased two-fold when given in combination with vatinoxan. The same phenomena were also observed with intravenous administration. Medetomidine plasma protein binding is high (85-90%). Medetomidine is mainly oxidized in the liver, a smaller amount undergoes methylation in the kidneys, and excretion is mainly via urine. Vatinoxan plasma protein binding is approximately 70%. Low levels are detectable in the central nervous system. Only a small amount (<5%) of vatinoxan dose has been found to be excreted via the urine.
Species not recordedOn-label (ON_LABEL)United States1 source record · View provenance
- Species not recorded · SPL section 34090-1 (CLINICAL PHARMACOLOGY SECTION) · United States · On-label (ON_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Literature references1
References are linked to this drug. Species applicability is not recorded here, so the species filter does not narrow this list. Imported dates do not retain their original precision; confirm dates in the original citation.
- Intramuscular injection of a commercially available medetomidine-vatinoxan hydrochloride mixture produces reliable sedation in sheep and goats with varying cardiopulmonary effects.
Study summary not available in the imported record. Open the original citation to review the study.
Sources: DailyMed, U.S. National Library of Medicine; PubMed, National Library of Medicine; openFDA, U.S. Food and Drug Administration.
Available products
Products listed in the Health Canada Drug Product Database for this active ingredient. A listing does not establish that a product is authorized for the clinical uses described on this page.