Medetomidina
Medetomidine
Medetomidine Hydrochloride
También conocido como: Domitor · Dorbene · Dormilan · Medetor · Sedastart · Sedator · Sededorm · MPV-785 · Medetomidine hydrochloride
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Evidencia posológica v13 auditada
Evidencia estructurada para el cálculoRefractory seizures (extra-label)
Requiere verificación veterinaria
NA
Contexto clínico obligatorio (7)
- 1. Medetomidine dosages depend on the combination of drugs used and the dosage(s) of the other drug(s). Dosage adjustments will also need to be made to account for the degree of desired sedation; type, duration, and pain level of the procedure, and patient temperament and body weight/size.
- 3. Premedication with medetomidine will significantly reduce the dose of the induction agent required and will reduce volatile anesthetic requirements for maintenance anesthesia. All anesthetic agents used for induction or maintenance of anesthesia should be administered to effect.
- 4. For all dosages, the low end of the dose range is generally appropriate for IV administration, whereas the mid-upper range is most appropriate for IM or SC administration. Higher dosages will provide more profound sedation and analgesia.
- 5. When SC administration is used, the speed of sedation is slower, and the level of sedation is lighter and inconsistent. For more predictable sedation, IM or IV administration is recommended.
- 6. The effects of medetomidine can be reversed with atipamezole.
- It is most often dosed by volume at ½ or same volume of medetomidine that was administered and given IM. See Atipamezole.
- The commercially available injection should be stored at room temperature (15°C-30°C [59°F-86°F]) and protected from freezing. Use within 28 days of first vial puncture.
Evidencia revisada no calculable (1)
Solo evidencia; no apta para cálculo automático
Light sedation (often also used for pre-anesthesia)
a) Light sedation (often also used for pre-anesthesia): 5 – 20 µg/kg IM, IV, SC 18
Contexto clínico obligatorio (7)
- 1. Medetomidine dosages depend on the combination of drugs used and the dosage(s) of the other drug(s). Dosage adjustments will also need to be made to account for the degree of desired sedation; type, duration, and pain level of the procedure, and patient temperament and body weight/size.
- 3. Premedication with medetomidine will significantly reduce the dose of the induction agent required and will reduce volatile anesthetic requirements for maintenance anesthesia. All anesthetic agents used for induction or maintenance of anesthesia should be administered to effect.
- 4. For all dosages, the low end of the dose range is generally appropriate for IV administration, whereas the mid-upper range is most appropriate for IM or SC administration. Higher dosages will provide more profound sedation and analgesia.
- 5. When SC administration is used, the speed of sedation is slower, and the level of sedation is lighter and inconsistent. For more predictable sedation, IM or IV administration is recommended.
- 6. The effects of medetomidine can be reversed with atipamezole.
- It is most often dosed by volume at ½ or same volume of medetomidine that was administered and given IM. See Atipamezole.
- The commercially available injection should be stored at room temperature (15°C-30°C [59°F-86°F]) and protected from freezing. Use within 28 days of first vial puncture.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
La medetomidina es un potente agonista adrenérgico alfa-2 sintético ampliamente utilizado en medicina veterinaria por sus profundas propiedades sedantes, analgésicas y relajantes musculares.
Las características clínicas clave incluyen:
- Respuesta cardiovascular bifásica: La vasoconstricción periférica inicial conduce a una hipertensión transitoria, seguida de una bradicardia refleja y una posterior normotensión o hipotensión leve.
- Reversibilidad: Sus efectos pueden revertirse rápida y completamente utilizando antagonistas alfa-2 específicos como el atipamezol.
- Estereoquímica: La medetomidina es una mezcla racémica de dos estereoisómeros. El enantiómero activo es la dexmedetomidina, que ha reemplazado en gran medida a la medetomidina racémica en muchos mercados veterinarios modernos.
- Sinergismo: Altamente sinérgico con opioides, ketamina y otros agentes anestésicos, lo que permite reducciones significativas en la dosis de los anestésicos concurrentes (efecto ahorrador de MAC).
Perla clínica: Aunque proporciona una excelente analgesia somática y visceral, los efectos sedantes suelen durar más que los analgésicos. Los pacientes pueden despertarse repentinamente si son estimulados por ruidos fuertes o manipulación brusca, incluso si parecen estar profundamente sedados.
Mecanismo de acción
Medetomidine produces its effects by binding to and activating pre- and postsynaptic alpha-2 adrenergic receptors in the central and peripheral nervous systems.
- Central Nervous System: Activation of alpha-2 receptors in the locus coeruleus → inhibition of adenylyl cyclase → decreased cAMP → efflux of potassium (hyperpolarization) → decreased release of norepinephrine. This suppression of sympathetic outflow results in profound sedation, anxiolysis, and analgesia.
- Cardiovascular System: Activation of peripheral alpha-1 and alpha-2b receptors in vascular smooth muscle → profound vasoconstriction → increased systemic vascular resistance (hypertension) → baroreceptor-mediated increased vagal tone → reflex bradycardia.
- Endocrine/Metabolic: Inhibits insulin release from pancreatic beta cells → transient hyperglycemia. Decreases antidiuretic hormone (ADH) release → increased diuresis.
Medetomidine is highly selective, with an alpha-2:alpha-1 selectivity ratio of 1620:1 (approximately 10 times more specific than xylazine).
Seguridad y advertencias
Contraindicaciones
- Cardiac disease
- Respiratory disorders
- Liver or kidney diseases
- Shock or severe debilitation
- Animals stressed due to heat, cold, or fatigue
- Pregnancy (insufficient safety data; use only if benefits clearly outweigh risks)
- Cardiovascular disease
- Systemic disease
- Geriatric patients
- Pregnant animals
- Conditions where vomiting is contraindicated (e.g., gastrointestinal foreign body, raised intraocular pressure)
- Diabetes mellitus
Efectos adversos
- Bradycardia (often profound)
- Atrioventricular (AV) blocks
- Decreased respiratory rate and potential apnea
- Hypothermia
- Increased urination (diuresis)
- Vomiting (especially in cats)
- Pain on intramuscular injection
- Blanched or cyanotic mucous membranes (due to peripheral vasoconstriction)
- Rarely: prolonged sedation, paradoxical excitation, hypersensitivity, death from circulatory failure
- Decreased cardiac output
- Initial hypertension followed by normotension/hypotension
- Vomiting (especially common after IM administration)
- Diuresis (due to ADH suppression)
- Transient hyperglycemia (due to decreased insulin)
- Mydriasis
- Decreased intraocular pressure
- Spontaneous arousal from deep sedation
Precauciones
- Agitated Patients: Dogs that are extremely agitated or excited may have a decreased response due to high circulating catecholamines overriding the receptor. Allow dogs to rest quietly before administration. Do not re-dose if they fail to respond.
- Age Extremes: Use with extreme caution in very young or geriatric animals due to reduced cardiovascular reserve.
- Hematologic: Medetomidine can inhibit ADP-induced platelet aggregation.
- Reversal: Treat medetomidine-induced bradycardia or excessive sedation with atipamezole rather than anticholinergics.
Interacciones farmacológicas
Controversial. Using anticholinergics to treat medetomidine-induced bradycardia can lead to severe hypertension, increased myocardial work, and arrhythmias. Concomitant use is generally discouraged, especially at higher medetomidine doses (>20 mcg/kg).
Synergistic enhancement of sedation and analgesia. Adverse cardiovascular and respiratory effects may also be pronounced. Reduced dosages and careful monitoring are advised.
When used after medetomidine, severe hypoxemia may occur. Significant dosage reductions of propofol are required along with adequate respiratory monitoring.
May reverse the effects of medetomidine, but atipamezole is the preferred and more specific reversal agent.
Significantly reduces the dose required for induction and maintenance of anesthesia.
Reduces the dose required to maintain anesthesia by up to 70%.
Contraindicated; may cause severe cardiovascular complications.
Synergistic sedation and analgesia (beneficial interaction).
Monitorización
- Level of sedation and analgesia
- Heart rate and rhythm (ECG recommended in high-risk patients)
- Body temperature (monitor for hypothermia)
- Respiratory rate and depth
- Pulse oximetry (SpO2)
- Heart rate and rhythm (bradycardia is expected, but monitor for severe arrhythmias)
- Blood pressure (initial hypertension followed by normotension/hypotension)
- Oxygen saturation (SpO2)
- Body temperature (risk of hypothermia due to reduced metabolic rate and peripheral vasoconstriction)
- Depth of sedation
Farmacocinética
Vida media
Absorción
Rapid onset after IV (5 minutes) or IM (10-15 minutes) injection. SC absorption is unreliable. Can be absorbed via oral mucosa (sublingually) but efficacy may be lower than IM.
Distribución
Highly lipophilic, allowing rapid penetration of the blood-brain barrier to exert central effects.
Metabolismo
Undergoes extensive hepatic biotransformation.
Eliminación
Metabolites are primarily excreted via the kidneys.
Sobredosis
Single doses of up to 5X (IV) and 10X (IM) have been tolerated in dogs, though severe adverse effects (profound bradycardia, AV blocks, respiratory depression) can occur. Death has occurred rarely in dogs (1 in 40,000) receiving 2X doses.
Important: Treatment of medetomidine-induced bradycardia with anticholinergic agents (atropine or glycopyrrolate) is not recommended due to the risk of severe hypertension, increased myocardial oxygen demand, and arrhythmias.
Atipamezole (an alpha-2 antagonist) is the safest and most effective choice to reverse medetomidine-induced cardiovascular and sedative effects.
Productos disponibles
Formulaciones
- Injection: 1 mg/mL in 10 mL multidose vials
- Injectable: 1 mg/ml solution
Veterinario
- Medetomidine HCl for Injection: 1 mg/mL in 10 mL multidose vials (Domitor®)
- Domitor 1 mg/ml solution for injection
- Dorbene 1 mg/ml solution for injection
- Dormilan 1 mg/ml solution for injection
- Medetor 1 mg/ml solution for injection
- Sedastart 1 mg/ml solution for injection
- Sedator 1 mg/ml solution for injection
- Sededorm 1 mg/ml solution for injection
Estado regulador
Classified as POM-V.
Classified as POM-V.
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Store commercially available injection at room temperature (15-30°C) and protect from freezing.
Información para el cliente
- Solo para uso profesional: Este fármaco es un potente sedante y coadyuvante anestésico que debe ser administrado y monitoreado exclusivamente por profesionales veterinarios.
- Apariencia esperada: Mientras esté sedada, la frecuencia cardíaca de su mascota disminuirá significativamente y sus encías pueden verse pálidas o ligeramente azuladas. Este es un efecto esperado del fármaco y es monitoreado de cerca por el equipo veterinario.
- Mantenga la calma: Aunque su mascota parezca profundamente dormida, los ruidos fuertes repentinos o una manipulación brusca pueden sobresaltarla y despertarla. Mantenga el entorno tranquilo y silencioso mientras se recupera.
- Reversión: El veterinario puede administrar un "agente de reversión" (atipamezol) para despertar a su mascota de forma rápida y suave después del procedimiento.
- Mascotas en riesgo: Asegúrese de que su veterinario esté al tanto de cualquier condición preexistente de corazón, hígado o riñón, o si su mascota está embarazada, ya que este fármaco puede no ser seguro en estas situaciones.
La referencia de medicamentos de VetSheet está destinada a profesionales veterinarios autorizados como ayuda para la toma de decisiones clínicas, no como sustituto del criterio profesional ni del prospecto actual del fabricante.