Mibolerone
Mibolerone is a potent **androgenic, anabolic, and antigonadotropic** 19-nor-steroid. * Historically marketed as Cheque® Drops, commercial availability is now an issue, and it is primarily obtained through compounding pharmacies. It is classified as a **Schedule III controlled substance** in the USA. * **Clinical uses** include the suppression of estrus, treatment of pseudocyesis (false pregnancy), and severe galactorrhea in female dogs. > **Warning:** Mibolerone has a very narrow therapeutic index in felines and is highly toxic to cats. It should **never** be used in feline patients.
Mecanismo: Mibolerone exerts its effects via a **negative feedback mechanism** on the anterior pituitary gland. * **Blocks luteinizing hormone (LH)** release → prevents follicular maturation → inhibits ovulation and corpus luteum development. * The net result is the suppression of the estrous cycle if administered prior to (up to 30 days) the onset of proestrus. * After discontinuation, the next estrus typically occurs within 7-200 days (average 70 days).
Dosificación por especie
- Suppression of estrus · 0.5-11 kg: 30 micrograms (0.3 mL) PO per day; 12-22 kg: 60 micrograms (0.6 mL) PO per day; 23-45 kg: 120 micrograms (1.2 mL) PO per day; >45 kg: 180 micrograms (1.8 mL) PO per day. German shepherds or German shepherd crosses: 180 micrograms (1.8 mL) PO per day; regardless of weight · PO · q24h · Treatment must begin at least 30 days prior to proestrus · If dog comes into estrus after receiving the drug for 30 or more days, stop drug and determine that the dog is not pregnant before resuming therapy. If owner compliance has been determined, increase dosage by 20-50%.
- Pseudocyesis (false pregnancy) · 10 times the dosage listed above for suppression of estrus · PO · q24h · 5 days
- Pseudocyesis (false pregnancy) · 16 micrograms/kg · PO · q24h · 5 days
- Cystic endometrial hyperplasia (CEH) · 30 micrograms/25lb. body weight · PO · q24h · 6 months
- Treatment of severe galactorrhea · 8-18 micrograms/kg · PO · q24h · 5 days · Once discontinued, prolactin may surge and galactorrhea resume.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Perianal adenoma or perianal adenocarcinoma
- Other androgen-dependent neoplasias
- Pregnant or lactating bitches
- Patients with ongoing or a history of liver or kidney disease
- Bedlington Terriers
- Cats
Efectos adversos
- Premature epiphyseal closure (in prepuberal females)
- Clitoral enlargement / hypertrophy
- Vaginitis / Vulvovaginitis
- Increased body odor
- Abnormal behavior (e.g., riding/mounting behavior)
- Urinary incontinence
- Voice deepening
- Enhanced clinical signs of seborrhea oleosa
- Epiphora (tearing)
- Hepatic changes (intranuclear hyaline bodies) and rare hepatic dysfunction
- Increased kidney weight
- Fatalities, thyroid dysfunction, and pancreatic dysfunction (in cats)
Interacciones farmacológicas
- Phenytoin · Increased seizure activity has been reported in a dog previously controlled on phenytoin.
- Progestins · Should generally not be used concurrently.
- Estrogens · Should generally not be used concurrently.
Monitorización
- Clinical signs of estrus
- Liver function tests (baseline, annual, or as needed)
- Physical examination of genitalia
Sobredosis
In dogs, the drug did not cause death in doses up to 30,000 micrograms/kg/day when administered to beagles for 28 days. In cats, dosages as low as 120 micrograms/day have resulted in fatalities.
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.