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Clinical particulars
Target species
Horses (mares)
Indications for use
In mares with significant follicular activity during the transitional period between seasonal anoestrus and the breeding season (follicles of at least 20-25 mm present at the beginning of treatment):
Suppression/prevention of oestrus (usually after 1 to 3 days of treatment) during the prolonged oestrus periods occurring during this period.
Control of the time of initiation of oestrus (approximately 90 % of mares show signs of oestrus within 5 days following the end of treatment) and synchronization of ovulation (60 % of mares ovulate between days 11 and 14 following the end of treatment).
Do not use in mares where uterine infection has been diagnosed.
Do not use in males.
Special warnings for each target species
In order to ensure effective use of the product, the presence of follicular activity in mares must be confirmed during the transitional period.
Special precautions for use
The medicated feed should be offered to mares being treated as soon as the product has been added, and not stored. Part consumed feed must be safely destroyed and not given to any other animal.
Operator warnings
- Women who may be, or are pregnant, should not use the product. Women of childbearing age should avoid contact with the product.
- This product should not be handled by persons with known or suspected progesterone-dependent tumours or thrombo-embolic disorders.
- Direct contact with the skin should be avoided. Personal protective clothing (gloves and overalls) must be worn when handling the product. Porous gloves may let this product pass through. Transcutaneous absorption may be even higher when the area is covered by an occlusive material, such as latex or rubber gloves. Accidental spillage on the skin should be washed off immediately with soap and water.
- Wash hands after treatment and before meals.
- In case of incidental contact with eye, rinse thoroughly with water for 15 minutes. Get medical attention.
- Effects of overexposure: repeated accidental absorption could lead to disruption of the menstrual cycle, uterine or abdominal cramping, increased or decreased uterine bleeding, prolongation of pregnancy or headache.
Adverse reactions
Adverse reactions, such as uterine infection, are extremely rare.
Use during pregnancy or lactation
Not applicable.
However, accidental administration is not detrimental as studies in mares have not produced any evidence of teratogenic, foetotoxic or maternotoxic effects.
Use during lactation is unlikely to have detrimental effects.
Griseofulvin may alter the effects of altrenogest if administered concomitantly with this product.
Amounts to be administered and administration route
For oral administration.
0.044 mg altrenogest per kg body weight per day, for 10 consecutive days.
Carefully withdraw the volume of product corresponding to the mare body weight (1 ml per 50 kg body weight) and administer this volume via oral route.
- 150, 300 and 1000 ml bottles: Wearing gloves remove the original cap and in its place screw on the luer lock cap. Keeping the bottle upright, screw the syringe onto the luer lock cap orifice, turn the bottle upside down, and carefully withdraw the solution from the bottle using the syringe.
Turn the bottle right way up before detaching the syringe. Securely replace the small cap on the luer lock cap.
- 250 ml bottles: Remove the white cap and the aluminium foil seal from the neck of the measuring compartment. Keeping the bottle upright, press the body of the bottle until the required volume of product is accumulated into the measuring compartment. Carefully pour the content of the measuring compartment on the mare feed.
The product should be added to the mare’s feed, at a single feeding per day, or directly administered into the mouth using a syringe.
No negative effects have been observed in horses following up to five times the recommended dose of altrenogest for 87 days and at the recommend dose for continuous periods up to 305 days.
Withdrawal periods
Meat and offal: 9 days.
Not authorised for use in lactating animals producing milk for human consumption.