Lorazepam
7-chloro-5-(2-chlorophenyl)-3-hydroxy-1,3-dihydro-2H-1,4-benzodiazepin-2-one
También conocido como: Ativan · Lorazepam Intensol · BRN-07599084 · CB-8133 · Ro-7-8408 · Wy-4036 · lorazapamum · anxiedin · azurogen · bonatranquan · delormetazepam · lorazin · lorazon · lorenin · norlormetazepam · novhepar · novolorazem · oChloroxazepam · sinestron · Lorazepamum
Revisado por el equipo veterinario de VetSheetActualizado 5 abr 2026Referencia veterinaria basada en la evidencia
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Dosis por especie
🌎 NA — North America🌍 EU — Europe
Perros
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| Status epilepticus (alternative to diazepam) | 0.2 mg/kg IV, IM or intranasal once | IV/IM/intranasal | once | — | 🌎 NA |
| Status epilepticus | 0.2 mg/kg IV once, followed by a bolus IV loading dose of levetiracetam at 60 mg/kg | IV | once | — | 🌎 NA |
| Fears, anxieties, phobias | 0.02-0.1 mg/kg PO once daily to three times a day | PO | q8-24h | — | 🌎 NA |
| Anxiolytic | 0.05-0.25 mg/kg PO q12-24h | PO | q12-24h | — | 🌎 NA |
| Fears/anxiety | 0.02-0.5 mg/kg PO q8h | PO | q8h | — | 🌎 NA |
| Fears, anxieties, phobias, aversions | 0.02-0.1 mg/kg q8-24h | PO | q8-24h | — | 🌎 NA |
| Short-term management of anxiety disorders | 0.02-0.1 mg/kg | PO | q12-24h | Short-term | 🌍 EU |
- Fears, anxieties, phobias: May be used on an as needed basis
- Fears/anxiety: The lowest dose and frequency that alleviate the fear should be used
- Fears, anxieties, phobias, aversions: Minimally sedating, may require 4 weeks to peak effect
- Short-term management of anxiety disorders: Start at the lower end of the dose range and gradually increase as needed.
Gatos
| Indicación | Dosis | Vía | Frecuencia | Duración | Región |
|---|---|---|---|---|---|
| Fears/anxiety | 0.03-0.08 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Fears, anxieties, phobias | 0.125 mg-0.25 mg total dose (¼-½ of a 0.5 mg tablet) once to twice a day | PO | q12-24h | — | 🌎 NA |
| Anxiolytic | 0.05-0.25 mg/kg PO q12-24h | PO | q12-24h | — | 🌎 NA |
| Short-term management of anxiety disorders | 0.02-0.1 mg/kg | PO | q12-24h | Short-term | 🌍 EU |
- Fears/anxiety: The lowest dose and frequency that alleviate the fear should be used
- Fears, anxieties, phobias: May be used on an as needed basis
- Short-term management of anxiety disorders: Start at the lower end of the dose range and gradually increase. Monitor closely for signs of hepatotoxicity.
Las dosis son una referencia clínica para profesionales veterinarios autorizados. Confirme siempre con el prospecto actual y cada paciente individual.
Resumen
El lorazepam es una benzodiacepina potente de acción intermedia utilizada en medicina veterinaria principalmente como ansiolítico para trastornos del comportamiento y como alternativa al diazepam para el manejo del status epilepticus.
Perla Clínica: A diferencia del diazepam, el lorazepam se somete a glucuronidación directa sin formar metabolitos intermedios activos. Esto lo convierte en una opción significativamente más segura para pacientes geriátricos, obesos o con compromiso hepático.
- Administración versátil: Puede administrarse por múltiples vías, incluyendo intranasal, intramuscular y sublingual/bucal, lo que lo hace altamente versátil para el manejo de convulsiones de emergencia en casa o en la clínica.
- Duración: Parece ser tan eficaz como el diazepam y puede poseer una duración de acción anticonvulsiva más prolongada, aunque esto no ha sido probado definitivamente en perros.
Mecanismo de acción
Lorazepam acts as a positive allosteric modulator at the GABA-A receptor.
- It binds to the benzodiazepine site on the GABA-A receptor complex → enhances the affinity of the receptor for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA).
- This increases the frequency of chloride channel openings → influx of chloride ions → hyperpolarization of the neuronal membrane → decreased neuronal excitability.
- This widespread CNS depression primarily affects the subcortical levels (limbic, thalamic, and hypothalamic), yielding anxiolytic, sedative, skeletal muscle relaxant, and anticonvulsant effects.
- Other postulated mechanisms include antagonism of serotonin and diminished release or turnover of acetylcholine in the CNS.
Seguridad y advertencias
Contraindicaciones
- Hypersensitivity to benzodiazepines
- Severe respiratory insufficiency (unless mechanically ventilated)
- Glaucoma
- Significant liver disease
- Significant kidney disease
- Pregnant animals
- Lactating animals
Efectos adversos
- Increased appetite
- Increased activity/excitement (paradoxical reaction)
- Vocalization
- Somnolence
- Lethargy
- Disinhibition (potential emergence of aggression)
- Drowsiness
- Mild transient incoordination (ataxia)
- Tremor and inappetence (associated with acute withdrawal)
Precauciones
Withdrawal: When using for negative behaviors, withdraw the drug gradually to avoid a rebound effect. Physical dependency has been induced in dogs; long-term regular usage requires gradual weaning.
Administration Warning: Injectable lorazepam must NOT be given intra-arterially; arteriospasm may occur resulting in necrosis.
Pregnancy: Designated FDA Category D in humans (evidence of fetal risk), but animal studies suggest relative safety at usual dosages. High doses just prior to delivery can cause 'floppy infant' syndrome.
Interacciones farmacológicas
Additive CNS effects
Decreased renal clearance of lorazepam
Increased CNS depression, irrational behavior
Decreased sedation from lorazepam
Increased lorazepam serum concentration
Inhibits the metabolism of lorazepam, potentially leading to increased plasma concentrations and prolonged sedation.
May inhibit the metabolism of lorazepam, increasing the risk of toxicity.
Additive CNS depression and sedation.
Monitorización
- Clinical efficacy (seizure control or anxiety reduction)
- Adverse effects (CNS depression, paradoxical excitation, ataxia)
- Behavioral changes (watch for paradoxical aggression or extreme sedation)
- Liver enzymes (ALT, AST, ALP, Bilirubin), especially in cats
- Appetite and water intake
Farmacocinética
Vida media
Absorción
In humans, absolute bioavailability is ~90% orally. Rapidly and completely absorbed after IM dosing. Sublingual has similar bioavailability to oral, but peaks sooner. In dogs, intranasal administration reaches 30 ng/mL in 3-9 minutes.
Distribución
High affinity for benzodiazepine receptors in the CNS. Brain concentrations may persist longer than serum levels. Small amounts are distributed into milk.
Metabolismo
Converted into inactive glucuronide forms in the liver in most species. Lack of active metabolites makes it safer for patients with liver dysfunction.
Eliminación
Dogs: Primary elimination route is via urine. Cats: Elimination is ~50% in urine (primarily as glucuronide) and 50% in feces.
Sobredosis
Overdoses of lorazepam are generally limited to CNS depression (confusion, lethargy, somnolence, decreased reflexes).
- Severe Toxicity: Very large overdoses can cause ataxia, hypotension, coma, and rarely death.
- Treatment: Standard protocols for removing/binding the drug in the gut (if orally ingested) and supportive systemic measures. Forced diuresis with IV fluids/electrolytes and mannitol may enhance excretion in patients with normal renal function.
- Antidote: Flumazenil may be considered for adjunctive treatment of serious overdoses, but it does not replace supportive therapy. Caution: Flumazenil is not recommended in patients with seizure disorders as it may induce seizures.
- Note: Analeptic agents (CNS stimulants like caffeine) are generally not recommended.
Productos disponibles
Formulaciones
- Concentrated Oral Solution
- Injection
- 1 mg oral tablets
- 2 mg/ml oral suspension
- 4 mg/ml injectable solution
Etiquetado para humanos
- Lorazepam Tablets: 0.5 mg, 1 mg, & 2 mg
- Lorazepam Concentrated Oral Solution: 2 mg/mL
- Lorazepam Injection: 2 mg/mL & 4 mg/mL
- Ativan 1 mg tablets
- Intensol 2 mg/ml oral suspension
- Lorazepam 4 mg/ml injectable solution
Estado regulador
POM (Prescription Only Medicine). Subject to national controlled substance regulations.
POM-V / POM. Controlled Drug Schedule 4 Part 1.
Sin datos reguladores para: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Almacenamiento y estabilidad
Tablets should be stored in well-closed containers at room temperature (20-25°C). Oral solution and injection should be stored refrigerated (2-8°C) and protected from light. Injection must be diluted just prior to IV use with an equal volume of D5W, normal saline, or sterile water. Do not use if discolored or if a precipitate forms.
Información para el cliente
El lorazepam es un medicamento utilizado para ayudar a controlar las convulsiones o manejar la ansiedad severa y las fobias en mascotas.
- Cambios en el apetito: Este medicamento puede aumentar el apetito de su mascota. Puede ser necesaria una restricción dietética diligente para evitar un aumento de peso no deseado.
- Cambios de comportamiento: Esté atento a cambios en los niveles de actividad. Puede causar somnolencia/letargo o, por el contrario, un aumento de la actividad, excitación y vocalización.
- No suspender abruptamente: No suspenda el tratamiento repentinamente sin la guía de su veterinario. Los animales que reciben este medicamento regularmente durante un período prolongado pueden desarrollar signos de abstinencia si no se les 'retira' adecuadamente.
- Salud hepática: Aunque aún no se ha reportado toxicidad hepática en animales que reciben lorazepam, un fármaco similar (diazepam) ha causado toxicidad hepática en raras ocasiones en gatos. Si nota vómitos, falta de apetito o coloración amarillenta en el blanco de los ojos o en las encías, contacte a su veterinario de inmediato.
- Consejo de administración: Las tabletas son relativamente insípidas y se desintegran fácilmente con la saliva. Si la administración es difícil, coloque la tableta dentro de la mejilla del paciente y sígala en un minuto aproximadamente con un pequeño premio para facilitar la deglución.
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.