Primaquine
Primaquine is an 8-aminoquinoline **antiprotozoal** agent primarily utilized in veterinary medicine as the drug of choice for treating ***Babesia felis*** in cats. - **Clinical Pearl**: While highly effective at managing clinical signs, it typically does not achieve complete parasitological cure (sterilization of the infection), and relapses may occur requiring repeated courses of therapy. - It also has potential utility against ***Hepatozoon canis*** in dogs and ***Plasmodium spp.*** (avian malaria) in birds. - **Caution**: Primaquine has an exceptionally narrow therapeutic index (safety margin) in felines, necessitating extreme precision in dosing.
Mecanismo: The exact antiprotozoal mechanism of action is not fully elucidated. - It is believed to **bind and alter protozoal DNA**. - **Pharmacological Pearl**: As an 8-aminoquinoline, it likely interferes with the parasite's mitochondrial function. It generates **reactive oxygen species (ROS)** → disrupts electron transport → causes severe cellular and oxidative damage to the protozoa.
Dosificación por especie
- Babesia felis · 0.5 mg (as base)/kg PO once daily · PO · q24h · 1-3 days · Dose is for primaquine base.
- Babesia felis · 1 mg (total dose per cat) primaquine phosphate PO every 36 hours for 4 treatments, then 1 mg (total dose) per cat every 7 days for 4 treatments · PO · q36h then q7d · 4 treatments each · The drug does not sterilize the infection.
- Babesia felis · Primaquine phosphate 1 mg/kg IM one time · IM · once · 1 time · IM dosage form must be compounded.
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
- Known hypersensitivity to primaquine
- Concurrent use of bone marrow suppressant medications
- Patients susceptible to granulocytopenia (e.g., lupus, rheumatoid arthritis)
- Glucose-6-Phosphate Dehydrogenase (G-6-PD) deficiency
- Pregnancy
- Lactation
Efectos adversos
- Vomiting (most common in cats)
- Nausea
- Myelosuppression
- Methemoglobinemia
- Hemolysis
Interacciones farmacológicas
- Quinacrine · May potentiate the toxicity of one another; use of primaquine within 3 months of quinacrine is not recommended.
- Bone Marrow Depressants (e.g., amphotericin B, azathioprine, chloramphenicol, antineoplastics) · Concurrent use may cause an increased risk for toxicity and severe myelosuppression.
- Hemolytic Drugs (e.g., acetohydroxamic acid, sulfonylureas, quinidine, sulfonamides) · Concurrent use may cause an increased risk for toxicity and hemolysis.
Monitoreo
- CBC (mandatory, monitor weekly while treating)
- Improved clinical signs (increased appetite and body weight)
- Improvement in anemia
Sobredosis
> **CRITICAL**: In cats, dosages **greater than 1 mg/kg** can be lethal. - **Management**: Overdoses should initially be handled aggressively using standardized protocols for removal of the drug from the gut (emesis, activated charcoal) to prevent absorption. - Provide intensive supportive care for potential methemoglobinemia, hemolysis, and myelosuppression. - Because of the potential seriousness of overdoses, it is strongly recommended to contact an animal poison control center for guidance immediately.
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.