Proligestone
**Proligestone** is a synthetic progestogen used primarily in veterinary medicine for the postponement or suppression of oestrus in bitches and queens. It is also authorized for the treatment of miliary dermatitis in cats, although specific glucocorticoids are generally preferred for this indication. > **Clinical Warning**: Proligestone carries risks typical of long-term progestogen use, including the potential development of cystic endometrial hyperplasia (pyometra), diabetes mellitus, and mammary neoplasia. It should be used with caution and is contraindicated in diabetic animals.
Mechanism: Proligestone alters the transcription of DNA → leads to alterations in cellular metabolism → mimics the physiological effects caused by endogenous **progesterone**.
Dosing by species
- Suppression of oestrus · 10-33 mg/kg depending on body weight (<5kg: 100-150mg; 5-10kg: 150-250mg; 10-20kg: 250-350mg; 20-30kg: 350-450mg; 30-45kg: 450-550mg; 45-60kg: 550-600mg; >60kg: 10 mg/kg) · SC · Once · Single dose · Given once for suppression. Inject into medial side of flank fold.
- Permanent postponement of oestrus · 10-33 mg/kg depending on body weight (see weight table) · SC · 1st dose before pro-oestrus, 2nd dose 3 months later, 3rd dose 4 months later, then every 5 months · Ongoing · Once dosing ceases, bitches may come into oestrus on average 6-7 months later, but it may take up to 3 years in some cases.
- Acromegaly · 10-33 mg/kg depending on body weight (see weight table) · SC · Monthly · Until signs of hair growth are evident
- Postponement of oestrus / Miliary dermatitis · Dose not explicitly specified in text; refer to manufacturer guidelines · SC · Not specified · Not specified · Authorized for miliary dermatitis, but specific glucocorticoids are preferred.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Diabetic animals (insulin requirements are likely to change unpredictably)
- Bitches before or at their first oestrus
Adverse effects
- Unpredictable duration of anoestrus (up to 3 years in some bitches)
- Temperament changes (listlessness and depression)
- Polyuria and polydipsia (increased thirst)
- Polyphagia (increased appetite)
- Cystic endometrial hyperplasia / Pyometra
- Diabetes mellitus
- Acromegaly
- Adrenocortical suppression
- Mammary enlargement, lactation, or neoplasia
- Injection site irritation
- Coat colour changes at the injection site
- Calcinosis circumscripta at the injection site
Monitoring
- Signs of pyometra (vaginal discharge, lethargy, polyuria/polydipsia)
- Blood glucose and clinical signs of diabetes mellitus (excessive thirst and urination)
- Mammary gland changes (enlargement, masses)
- Injection site reactions
Overdose
No specific information provided in the monograph. Overdosage may increase the risk and severity of progestational side effects, including cystic endometrial hyperplasia, diabetes mellitus, and adrenocortical suppression. Treatment is supportive.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.