Baclofen
Baclofen is a centrally acting skeletal muscle relaxant. In veterinary medicine, it is primarily used off-label in dogs to manage functional urinary retention by decreasing urethral sphincter tone. **Clinical Pearls:** * Baclofen has a very narrow margin of safety in animals, and toxicosis is frequently reported due to accidental ingestion of human medications. * **Strictly contraindicated in cats.** * Because it crosses the blood-brain barrier poorly at therapeutic doses, its central effects are limited, but massive overdoses lead to profound CNS depression.
Mecanismo: Baclofen is a structural analog of the inhibitory neurotransmitter **GABA** (gamma-aminobutyric acid). It acts primarily as a **GABA-B receptor agonist** at the spinal cord level. * Activation of **GABA-B receptors** → hyperpolarization of primary afferent nerve terminals → inhibition of the release of excitatory neurotransmitters (such as glutamate and aspartate). * This reduces **gamma efferent neuronal activity**, decreasing the frequency and amplitude of muscle spasms. * In the lower urinary tract, it specifically reduces **striated sphincter tone** in the urethra, facilitating bladder emptying.
Dosificación por especie
- To treat urinary retention by decreasing urethral resistance · 1-2 mg/kg · PO · q8h
- To treat urinary retention by decreasing urethral resistance · 5-10 mg (total dose) · PO · q8h
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Cats (strictly not recommended)
- Hypersensitivity to baclofen
Efectos adversos
- Sedation
- Weakness
- Pruritus
- Salivation
- Gastrointestinal distress (nausea, abdominal cramping)
Interacciones farmacológicas
- CNS Depressants · May cause additive CNS depression
Monitorización
- Efficacy (improvement in urination)
- Adverse effects (sedation, weakness, GI signs)
Sobredosis
Baclofen has a narrow margin of safety in dogs. * **Toxicity Thresholds:** Deaths have been reported at doses as low as **8 mg/kg**. Clinical signs can appear at doses as low as **1.3 mg/kg**. * **Clinical Signs:** Vomiting, depression, vocalization, hypersalivation, ataxia, hypotonia, muscle twitching, hypothermia, and lethargy. Massive overdoses may cause respiratory depression, coma, or seizures. * **Onset & Duration:** Signs can occur 15 minutes to 7 hours post-ingestion and persist for hours to days. * **Treatment:** * In alert patients, empty the gut (emesis/lavage). * **Avoid** magnesium-containing saline cathartics (may compound CNS depression). * Forced fluid diuresis may enhance excretion. * Mechanical ventilation for respiratory depression. * **Cyproheptadine** (1.1 mg/kg PO or PR) may alleviate vocalization and disorientation. * Atropine may improve ventilation, HR, BP, and body temperature. * Diazepam for seizures. * **Intravenous Lipid Emulsion (ILE)** may be useful as baclofen is lipid-soluble.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.