Isoxsuprine
Isoxsuprine is a **peripheral vasodilator** primarily used in veterinary medicine for the management of **navicular disease** in horses, though its oral efficacy has been recently questioned due to poor bioavailability. * **Equine Use**: Historically prescribed to improve blood flow to the hoof and podotrochlea. Also used anecdotally as a tocolytic agent. * **Canine Use**: Anecdotally used for **Raynaud's-like syndrome** (periodic digital cyanosis, onychogryphosis). * **Avian Use**: May improve microcirculation. **Clinical Pearl**: Because of its significant first-pass metabolism, oral administration in horses often fails to achieve detectable plasma concentrations, leading many modern practitioners to question its clinical utility for navicular syndrome compared to other hemorrheologic agents like pentoxifylline.
Mecanismo: Isoxsuprine acts as a **beta-adrenergic agonist** (specifically **beta-2 receptors**), though its vasodilatory effects may also stem from direct smooth muscle relaxation independent of beta-receptors. * **Vasodilation**: Stimulates **beta-2 receptors** → increases intracellular **cAMP** → decreases intracellular calcium → **vascular smooth muscle relaxation** (primarily in skeletal muscle). * **Uterine Relaxation**: Relaxes uterine smooth muscle, acting as a tocolytic agent. * **Hemorrheologic Effects**: At high doses, it can decrease blood viscosity and reduce platelet aggregation. * **Cardiac Effects**: May exhibit positive inotropic and chronotropic effects on the heart via **beta-1 receptor** stimulation. * **Analgesia**: Does not appear to possess significant analgesic properties in horses.
Dosificación por especie
- Treatment of orthopedic conditions, such as navicular disease (For long break-over if therapeutic shoeing does not correct) · 1.2 mg/kg PO q8h for 3 weeks. The dose is decreased as soundness improves, to 1.2 mg/kg PO once daily for 6 weeks, then every other day until heel first landing occurs. · PO · q8h initially · 3 weeks initially, then tapered · Phenylbutazone is added if lameness is greater than grade II on a scale of I-V, or until recheck occurs. The drug is classified as a 'blocking' agent by the AHSA.
- Treatment of orthopedic conditions, such as navicular disease (To increase the circulation to the podotrochlea) · 0.6-1.2 mg/kg twice daily until sound, then decreased to once daily for 2 weeks then further decreased to every other day. · PO · twice daily initially · Until sound, then tapered
- Treatment of orthopedic conditions · 0.6-2 mg/kg PO q12h · PO · q12h
- As a tocolytic agent · 0.4-0.6 mg/kg IM or PO twice daily · IM or PO · twice daily · Efficacy is unproven and oral bioavailability appears highly variable.
- Treatment of 'Raynaud-like' disease · 1 mg/kg/day PO · PO · daily
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
- Immediately post-partum
- Presence of arterial bleeding
Efectos adversos
- CNS stimulation (uneasiness, hyperexcitability, nose-rubbing)
- Sweating
- Hypotension
- Tachycardia
- Gastrointestinal disturbances
Monitoreo
- Clinical efficacy (improvement in lameness or digital circulation)
- Adverse effects (tachycardia, GI disturbances, CNS stimulation)
Sobredosis
Serious toxicity is unlikely in horses after an inadvertent oral overdose due to poor bioavailability. * **Clinical Signs**: CNS stimulation (uneasiness, hyperexcitability, nose-rubbing), sweating, hypotension, tachycardia, and GI disturbances. * **Treatment**: Provide supportive care. Treat CNS hyperexcitability with **diazepam**, and hypotension with **intravenous fluids**.
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.