N-butylscopolammonium bromide
N-butylscopolammonium bromide (also known as hyoscine butylbromide) is a potent, injectable **anticholinergic** and **antispasmodic** agent primarily used in equine medicine. * **Key Clinical Use**: Rapid relief of abdominal pain associated with spasmodic colic, flatulent colic, and simple impactions in horses. It is also used to facilitate rectal examinations and colonoscopy. * **Clinical Pearl**: Because it is a **quaternary ammonium compound**, it is highly polar and does *not* readily cross the blood-brain barrier. This means it provides excellent peripheral antispasmodic effects on the gastrointestinal and urinary tracts without the profound central nervous system (CNS) side effects (such as excitement or severe sedation) often seen with tertiary amines like atropine or scopolamine. * It has a much shorter duration of action than atropine, making it ideal for brief interventions where prolonged ileus is undesirable.
Mecanismo: N-butylscopolammonium bromide acts as a **competitive antagonist** at **muscarinic acetylcholine receptors** located on smooth muscle cells. * **Mechanism**: Blocks acetylcholine binding → prevents intracellular calcium release → induces profound relaxation of gastrointestinal and urinary smooth muscle. * **Pathway**: Parasympathetic inhibition → decreased GI peristalsis and reduced rectal pressure. * **Duration**: Visceral antinociceptive and spasmolytic effects are brief, typically lasting 15-20 minutes in horses.
Dosificación por especie
- Control of abdominal pain (colic) associated with spasmodic colic, flatulent colic, and simple impactions · 0.3 mg/kg (30 mg or 1.5 mL per 100 kg of body weight) · slow IV · one time
- To treat esophageal obstruction · 0.3 mg/kg · IV · once · Administer with oxytocin (0.11-0.22 Units/kg IV once). Oxytocin use should be avoided in mares, or dose significantly reduced. Do not use in pregnant mares.
Las dosis son una referencia clínica para médicos veterinarios. Confirme siempre con la información vigente del producto y el paciente individual.
Vías de administración
Contraindicaciones
- Impaction colics associated with ileus
- Glaucoma
- Horses intended for food purposes
- Nursing foals
- Pregnant or lactating mares
Efectos adversos
- Transient tachycardia
- Decreased borborygmal sounds
- Transient pupil dilation
- Decreased secretions
- Dry mucous membranes
Interacciones farmacológicas
- ATROPINE or other anticholinergic agents · May cause additive effects if used with N-butylscopolammonium
- METOCLOPRAMIDE and other drugs that have cholinergic-like actions on the GI tract · These drugs and N-butylscopolammonium may counteract one another's actions on GI smooth muscle
Monitoreo
- Heart rate (Note: heart rate cannot be used as indicator for pain for the first 30 minutes after administration)
- GI motility via gut sounds and feces output
Sobredosis
Dosages up to 10X (3 mg/kg) were administered to horses as part of preapproval studies. Clinical effects noted included dilated pupils (returned to normal in 4-24 hours), tachycardia (returned to normal within 4 hours) and dry mucous membranes (returned to normal in 1-2 hours). Gut motility was inhibited, but returned to baseline within 4 hours and normal feces were seen within 6 hours. Two of the four horses treated at 10X dosage developed mild signs of colic which resolved without further treatment.
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.