Naloxona
Naloxone
Naloxone hydrochloride, N-allylnoroxymorphone
También conocido como: Narcan · N-allylnoroxymorphone · naloxona · EN-15304 · naloxoni · Naloxonum · Naloxone hydrochloride
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Evidencia posológica v13 auditada
Evidencia revisada no calculableEvidencia revisada no calculable (2)
Solo evidencia; no apta para cálculo automático
Green tree monitors/reversal of butorphanol
TABLE 127.5. Agent: Naloxone. Dosage: 4 mg/kg IM95. Species/Comments: Green tree monitors/reversal of butorphanol.
Solo evidencia; no apta para cálculo automático
Corn snakes, bearded dragons, red-eared sliders/µ-opioid agonist reversal
TABLE 127.5. Agent: Naloxone. Dosage: 0.04–2 mg/kg SC304,305,307,309. Species/Comments: Corn snakes, bearded dragons, red-eared sliders/µ-opioid agonist reversal.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
La naloxona es un antagonista puro de los receptores opioides utilizado principalmente en medicina veterinaria para revertir los efectos de los agonistas opioides, específicamente la depresión respiratoria, la sedación y la disforia. Se considera un antídoto vital en casos de sobredosis por opioides.
Más allá de su uso principal como agente de reversión, la naloxona se está investigando para el tratamiento de diversas formas de shock (séptico, hipovolémico o cardiogénico) y puede emplearse como herramienta diagnóstica o terapéutica para frenar comportamientos de automutilación (como perseguirse la cola) al bloquear las endorfinas endógenas.
Perla clínica: La naloxona no posee actividad analgésica propia. Cuando se utiliza para revertir la depresión respiratoria inducida por opioides, revertirá simultáneamente los efectos analgésicos del opioide, lo que puede provocar un retorno repentino del dolor y la consiguiente liberación de catecolaminas.
Mecanismo de acción
Naloxone acts as a competitive antagonist at opioid receptors. It binds primarily to the mu (μ) receptor, but also has affinity for kappa (κ) and sigma (σ) receptors.
By occupying these receptors without activating them, it displaces opioid agonists → rapid reversal of opioid-induced respiratory and CNS depression.
At very high doses, naloxone may exhibit additional pharmacologic activity, including GABA antagonism and the ability to increase dopamine levels.
Seguridad y advertencias
Contraindicaciones
- Hypersensitivity to naloxone
- Indiscriminate use in animals that have undergone major surgery or trauma (due to severe pain from analgesia reversal)
Efectos adversos
- Reversal of analgesia (return of pain)
- Acute withdrawal syndrome in opioid-dependent patients
- CNS excitement (especially if used in meperidine overdose)
- Seizures (at very high doses, likely secondary to GABA antagonism)
- Acute severe discomfort or pain (due to sudden loss of analgesia)
- Antanalgesic effects in opioid-naïve subjects
- Transient elevation of unconsciousness (at low doses)
Precauciones
Important Warning: The duration of action of naloxone (45-90 minutes) is often shorter than the opioid it is reversing. Patients may slip back into respiratory depression and require re-dosing or continuous ventilatory support.
- Use with caution in animals with preexisting cardiac abnormalities.
- Use cautiously in opioid-dependent animals or those that have received exceedingly large doses of narcotics, as it may precipitate an acute withdrawal syndrome.
- Meperidine Toxicity: Naloxone is reportedly not effective for reversing meperidine-induced seizures and may elicit CNS excitement if normeperidine excitotoxicity is present. Avoid unless severe respiratory depression is present without ventilatory support.
- Buprenorphine: Naloxone is not a good reversal agent for buprenorphine due to buprenorphine's high receptor affinity; massive doses (100X usual) may be required.
Interacciones farmacológicas
Naloxone may antagonize the effects of these agents (respiratory depression, analgesia). It should not be relied upon to treat respiratory depression caused by buprenorphine.
Naloxone may reduce the hypotensive and bradycardic effects of clonidine; potentially useful for clonidine overdoses.
Naloxone may increase the CNS effects of yohimbine (anxiety, tremors, nausea, palpitations) and increase plasma cortisol levels.
Naloxone reverses the analgesic, sedative, and respiratory depressant effects of opioid agonists.
Buprenorphine binds tightly to opioid receptors; naloxone may not fully reverse its effects or may require much higher doses.
Monitorización
- Respiratory rate and depth
- CNS function (level of sedation/arousal)
- Pain associated with opiate reversal
- Respiratory rate and effort
- Level of consciousness / sedation score
- Pain score (monitor for acute pain upon reversal)
- Heart rate and blood pressure
Farmacocinética
Vida media
Absorción
Minimally absorbed orally (rapidly destroyed in the GI tract). Very rapid onset of action when given IV (1-2 minutes). IM onset is generally within 5 minutes. Duration of action usually persists from 45-90 minutes, but may act for up to 3 hours.
Distribución
Distributed rapidly throughout the body with high levels found in the brain, kidneys, spleen, skeletal muscle, lung, and heart. Readily crosses the placenta.
Metabolismo
Metabolized in the liver, principally via glucuronidative conjugation.
Eliminación
Metabolites are excreted into the urine.
Sobredosis
Naloxone is considered a very safe agent with a very wide margin of safety. However, massive overdoses have initiated seizures in a few patients, which is theorized to be secondary to GABA antagonism.
Productos disponibles
Formulaciones
- Injection: 0.4 mg/mL
- Neonatal Injection: 0.02 mg/mL
- Injectable: 0.02 mg/ml solution
- Injectable: 0.4 mg/ml solution
Veterinario
- Naloxone 0.02 mg/ml injectable solution
- Naloxone 0.4 mg/ml injectable solution
Etiquetado para humanos
- Naloxone HCl Injection: 0.4 mg/mL (400 micrograms/mL) in 1 mL amps, syringes and 1 mL, 2 mL, & 10 mL vials (Narcan)
- Naloxone HCl Neonatal Injection: 0.02 mg/mL in 2 mL vials
- Narcan 0.4 mg/ml injectable solution
- Narcan nasal spray
Estado regulador
POM (Prescription Only Medicine)
POM-V
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Store at room temperature (15-30°C) and protect from light. Sterile water for injection is the recommended diluent. When given as an IV infusion, either D5W or normal saline should be used. Do not mix with solutions containing sulfites, bisulfites, long-chain or high molecular weight anions, or any solutions at alkaline pH.
Información para el cliente
- Propósito: La naloxona es un medicamento de emergencia utilizado para revertir los efectos de los analgésicos opioides o tratar sobredosis por opioides.
- Qué esperar: Su mascota puede despertar rápidamente de la sedación. Debido a que la naloxona revierte el efecto del analgésico, su mascota podría experimentar un retorno repentino del dolor.
- Monitoreo: Los efectos de la naloxona pueden desaparecer antes que los del opioide. Observe a su mascota de cerca por si reaparece una somnolencia extrema, respiración lenta o falta de respuesta.
- Administración: Generalmente es administrada por un profesional veterinario, pero en algunos casos (como en cachorros o gatitos recién nacidos), es posible que se le indique colocar una gota debajo de la lengua.
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.