Quinacrine
**Quinacrine** is a synthetic acridine derivative primarily used as an antiprotozoal and anthelmintic agent. Historically, it was utilized for the treatment of **Giardia**, **Leishmania**, and **coccidia** infections. However, its use in modern veterinary medicine has largely been superseded by safer and more effective alternatives (such as metronidazole or fenbendazole for giardiasis). **Clinical Pearls:** * May improve clinical signs of giardial infection but often fails to completely eliminate the organism. * Can cause a harmless yellow discoloration of the skin and urine, which should not be confused with icterus/jaundice. * Commercial availability is currently a significant issue; it typically must be compounded. * Considered a potential teratogen and should be avoided in pregnant animals unless absolutely necessary.
Mecanismo: The exact antiprotozoal mechanism against *Giardia* is not fully elucidated, but it involves multiple pathways: * **DNA Intercalation**: Binds to DNA by inserting itself between adjacent base pairs → inhibits **RNA transcription** and **translocation**. * **Metabolic Inhibition**: Interferes with electron transport and inhibits **succinate oxidation**. * **Enzyme Inhibition**: Inhibits **cholinesterase**. * In humans, it binds to nucleoproteins to suppress lupus erythematosus (LE) cell factor.
Dosificación por especie
- Giardia · 9 mg/kg PO once daily · PO · q24h · 6 days
- Coccidiosis · 10 mg/kg PO once daily · PO · q24h · 5 days
- Giardia · 11 mg/kg PO q24h · PO · q24h · 12 days
- Coccidiosis · 10 mg/kg PO once daily · PO · q24h · 5 days
- Giardia or other susceptible protozoa (second-choice) · 6.6 mg/kg PO q12h · PO · q12h · 5 days
- Giardia or other susceptible protozoa (second-choice) · 9 mg/kg PO q24h · PO · q24h · 6 days
- Hemoprotozoal infections · 19-100 mg/kg PO q48h (every other day) · PO · q48h · 2-3 weeks
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
- Hepatic dysfunction (relative)
- Pregnancy (relative, potential teratogen)
- Psychotic disorders (in humans)
- Psoriasis (in humans)
- Porphyria (in humans)
Efectos adversos
- Yellowing of skin and urine (benign)
- Anorexia
- Nausea and vomiting
- Diarrhea
- Abnormal behaviors ('fly biting', agitation)
- Lethargy
- Pruritus
- Fever
- Hypersensitivity reactions (rare)
- Hepatopathy (rare)
- Aplastic anemia (rare)
- Corneal edema (rare)
- Retinopathy (rare)
Interacciones farmacológicas
- Alcohol · May cause a 'disulfiram-like' reaction if used concurrently.
- Hepatotoxic Drugs · Quinacrine concentrates in the liver; use with caution with other hepatotoxic agents.
- Primaquine · Quinacrine increases the toxicity of primaquine; do not use simultaneously.
Monitoreo
- Efficacy (fecal exams, reduction in diarrhea)
- Adverse effects (GI upset, behavioral changes)
Sobredosis
**Acute Toxicity:** Overdosage can be severe and potentially fatal. * **Clinical Signs**: CNS excitation (including seizures), severe GI disturbances, vascular collapse, and cardiac arrhythmias. * **Treatment**: * Gut emptying protocols (emesis/lavage, activated charcoal). * Supportive and symptomatic therapies. * Urinary acidification (e.g., with ammonium chloride) and forced diuresis with adequate fluid therapy to enhance renal excretion.
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.