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Megestrol acetate · Laboratorios König S.A.

1 form: tablet. In force in Georgia: 1 of 1 (veterinary register).

Forms and doses1 of 1 in force in Georgia

The dose from the product's label, by species and weight. Check the label of the pack you use.

Choose species and weight; the matching row will be highlighted.
Form Species Dose Frequency Georgia
20 mg/tablet, Tablet · Cat Cat Estrus Prevention · By mouth: 1/4 tabletEstrus Interruption · By mouth: 1/2 tabletSuppression of Sexual Behaviour · By mouth: 1/2 tabletMiliary Dermatitis · By mouth: 1/2 tabletEosinophilic Granuloma · By mouth: 1/2 tablet - Georgia Yes, veterinary
In force until 30 Jan 2031
Veterinary (National Food Agency)
In the register: სინგესტარი®
№ 001067
Verified on: 21 Oct 2026
20 mg/tablet, Tablet · Dog Dog Estrus Prevention · By mouth: 1/4 tablet per 10 kgEstrus Interruption · By mouth: 1 tablet per 10 kgSuppression of Sexual Behaviour · By mouth: 1–2 tablets per 10 kgFalse Pregnancy · By mouth: 1 tablet per 10 kgEstrogen-dependent Tumours · By mouth: 1 tablet per 10 kgPerianal Gland Adenoma · By mouth: 1 tablet per 10 kgProstatic Hypertrophy · By mouth: 1 tablet per 10 kg - Georgia Yes, veterinary
In force until 30 Jan 2031
Veterinary (National Food Agency)
In the register: სინგესტარი®
№ 001067
Verified on: 21 Oct 2026
Details: pack, label wording, sources, registration

Singestar 20 mg/tablet, Tablet

megestrol acetate 20 mg tablets, N8
vetman assessment
vetman’s 10-point assessment brings together a product’s regulatory credibility, clinical efficacy, safety and practicality. Cost-effectiveness is assessed only when reliable data are available. It is informational and does not replace a veterinarian’s clinical judgment for an individual patient.
Dog Full dog label: oestrus prevention, postponement and suppression in bitches with megestrol acetate 20 mg tablets dosed per 10 kg, plus the labelled courses for male dogs
4.9/10
Weak evidence support
vetman assessment

Singestar

megestrol acetate 20 mg tablets, N8
Assessed clinical scopeDog · Full dog label: oestrus prevention, postponement and suppression in bitches with megestrol acetate 20 mg tablets dosed per 10 kg, plus the labelled courses for male dogs · By mouth
Care settingVeterinary prescription for a healthy, sexually mature dog after excluding pregnancy and uterine and mammary disease, with exact cycle timing and follow-up checks
vetman score 4.9/10 Weak evidence support
Evidence confidence: Low Georgia: Yes, veterinary · № 001067 · Verified on 21 Oct 2026

A weak option: an effective, old oestrus-control drug whose uterine, mammary and endocrine risks make it a short-term tool only. Surgical neutering, or an EU-authorised deslorelin implant in male dogs, is the safer long-term choice.

Regulatory and scientific credibility4.5/10

The exact product is registered in Georgia (001067, valid to 2031) with a 2012 Argentine manufacturer leaflet, but it has no EU, UK or US authorisation documented in the reviewed evidence, and the Georgian record even lists 7.14 g instead of 20 mg per tablet.

Clinical efficacy6.5/10

Megestrol acetate at about 2 mg/kg daily for 8 days from early pro-oestrus is a long-established way to suppress or postpone oestrus in bitches, but timing is critical and no study of this product exists.

Safety and tolerability3.5/10

Progestogens can cause cystic endometrial hyperplasia and pyometra, mammary nodules, insulin resistance and acromegaly in dogs; short labelled courses lower these risks but do not remove them.

Clinical practicality5.5/10

One tablet per 10 kg is easy to give, but success depends on starting at the right cycle stage, and several regimens run for weeks or months.

Full-course cost-effectiveness-

No verified current Georgian price or patient-adjusted course cost was found; foreign prices were not substituted.

Important safety and use flags

  • Do not use in pregnancy, before puberty, or with uterine or mammary disease or diabetes.
  • Watch for vaginal discharge, lethargy, thirst or abdominal swelling after a course; pyometra can develop weeks later.
  • Start at the first signs of pro-oestrus or at the time the label sets; late starts fail and raise uterine risk.
  • Palpate the mammary glands and check glucose in dogs on repeated or maintenance courses.
  • The Georgian register lists 7.14 g per tablet; the manufacturer leaflet states 20 mg, which the dose table uses.
Assessment sources
  1. König Singestar2012
  2. Georgia NFA register 20262026
  3. Canine estrus control2024
  4. Estrous-cycle manipulation2025
  5. EMA Suprelorin EPAR2024
Assessed: 23 Oct 2026The overall score uses 25/25/25/15/10 weights. An unassessed price is excluded and the remaining weights are proportionally renormalised.
Cat Full cat label: oestrus postponement and suppression in sexually mature queens with megestrol acetate 20 mg tablets given as quarter or half tablets, plus the further labelled short and maintenance courses
4.6/10
Weak evidence support
vetman assessment

Singestar

megestrol acetate 20 mg tablets, N8
Assessed clinical scopeCat · Full cat label: oestrus postponement and suppression in sexually mature queens with megestrol acetate 20 mg tablets given as quarter or half tablets, plus the further labelled short and maintenance courses · By mouth
Care settingVeterinary prescription for a healthy, sexually mature cat after excluding pregnancy, uterine and mammary disease and diabetes, with planned follow-up checks
vetman score 4.6/10 Weak evidence support
Evidence confidence: Low Georgia: Yes, veterinary · № 001067 · Verified on 21 Oct 2026

A weak option: it does stop oestrus, but long-term progestogen use in cats risks diabetes, mammary tumours and pyometra. Surgical neutering is the standard for lasting control; keep any hormonal course short and supervised.

Regulatory and scientific credibility4.5/10

The exact product is registered in Georgia (001067, valid to 2031) with a 2012 Argentine manufacturer leaflet, but it has no EU, UK or US authorisation documented in the reviewed evidence, and the Georgian record even lists 7.14 g instead of 20 mg per tablet.

Clinical efficacy6.0/10

Megestrol acetate reliably postpones or suppresses oestrus in queens, as reference texts confirm, but no study of this product exists and the effect ends when dosing stops.

Safety and tolerability3.0/10

Cats are especially sensitive to progestogens: diabetes mellitus, adrenal suppression, mammary hyperplasia and tumours, pyometra and weight gain are documented, and the risk grows with dose and duration up to the labelled 18 months.

Clinical practicality5.0/10

Oral dosing at home is simple, but the 20 mg tablet must be split into quarters or halves for cats, and the label carries many different regimens that are easy to confuse.

Full-course cost-effectiveness-

No verified current Georgian price or patient-adjusted course cost was found; foreign prices were not substituted.

Important safety and use flags

  • Do not use in pregnancy, before puberty, or with uterine or mammary disease, diabetes or a history of mammary nodules.
  • Check blood or urine glucose and palpate the mammary glands before and during any course longer than a few weeks; stop at the first sign of increased thirst, urination or mammary swelling.
  • Starting at the wrong cycle stage raises pyometra risk; follow the labelled cycle stage for each regimen exactly.
  • Do not combine with glucocorticoids or other progestogens; together they add to diabetes and adrenal suppression risk.
  • Megestrol does not replace surgical neutering, and reference texts advise against it for behaviour problems in cats. The Georgian register lists 7.14 g per tablet; the manufacturer leaflet states 20 mg.
Assessment sources
  1. König Singestar2012
  2. Georgia NFA register 20262026
  3. Feline estrus control2024
  4. Estrous-cycle manipulation2025
  5. Megestrol behaviour warning2026
Assessed: 23 Oct 2026The overall score uses 25/25/25/15/10 weights. An unassessed price is excluded and the remaining weights are proportionally renormalised.
Composition / strength
Megestrol acetate20 mg/tablet
Formulation Type
Tablet
Administration route
By mouth
Manufacturer
Laboratorios König S.A. · Argentina
Manufacturer (register)
Laboratorios Konig S.A., Argentina
Manufacturer and country as in the veterinary medicines register (National Food Agency), row 1658, 19 Oct 2026.
Source: NFA veterinary medicines register ↗
Registration
Georgia Yes, veterinary
In force until 30 Jan 2031
Veterinary (National Food Agency)
In the register: სინგესტარი®
№ 001067
Verified on: 21 Oct 2026
Controlled in Georgia
Unknown
Cat
WeightEstrus Prevention · By mouthEstrus Interruption · By mouthSuppression of Sexual Behaviour · By mouthMiliary Dermatitis · By mouthEosinophilic Granuloma · By mouth
Any weight 1/4 tablet 1/2 tablet 1/2 tablet 1/2 tablet 1/2 tablet
  • Estrus Prevention · By mouth (once daily for no longer than 2 months): Queens in breeding season but not in heat. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Estrus Interruption · By mouth (once daily for 7 days, then 1-2 times weekly): Queens only; then continue 1/4 tablet once or twice weekly. Start at heat signs. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Suppression of Sexual Behaviour · By mouth (daily 7 days, then reduced daily for 14 days): Cats: then 1/4 tablet daily for 14 days; maintenance 1/4 tablet once or twice weekly. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Miliary Dermatitis · By mouth (daily 7 days, then 1/4 tablet twice weekly until cure): Maintenance may be 1/4 tablet every 15 days. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Eosinophilic Granuloma · By mouth (every other day, then once weekly after regression starts): Continue once weekly until complete regression. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
Source:
König Singestar
Manufacturer material
Information published by the maker or a seller, such as a datasheet or product page. A medicines regulator has not necessarily reviewed it.
Singestar tablets - official product page and package leaflet
Official manufacturer instruction, 2012
Dog
WeightEstrus Prevention · By mouthEstrus Interruption · By mouthSuppression of Sexual Behaviour · By mouthFalse Pregnancy · By mouthEstrogen-dependent Tumours · By mouthPerianal Gland Adenoma · By mouthProstatic Hypertrophy · By mouth
Any weight 1/4 tablet per 10 kg 1 tablet per 10 kg 1–2 tablets per 10 kg 1 tablet per 10 kg 1 tablet per 10 kg 1 tablet per 10 kg 1 tablet per 10 kg
  • Estrus Prevention · By mouth (once daily for 30-40 days): Bitches only; start 15 days before the desired effect. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Estrus Interruption · By mouth (once daily for 8 days): Bitches only; normal regimen, start when heat signs appear. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Suppression of Sexual Behaviour · By mouth (once daily for 14 days; maintenance may follow): Male dogs: maintenance may be 1/2 tablet/10 kg once or twice weekly. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • False Pregnancy · By mouth (once daily for 8 days): Bitches only. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Estrogen-dependent Tumours · By mouth (daily 5 days, then reduced for at least 10 days): Bitches only; then continue 1/2 tablet/10 kg daily for 10 days or more. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Perianal Gland Adenoma · By mouth (once daily for at least 20 days): Dogs; after surgery, maintenance may be 1/2 tablet/10 kg once or twice weekly. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
  • Prostatic Hypertrophy · By mouth (once daily for 10 days, then twice-weekly reduced dose): Male dogs; after 10 days continue 1/2 tablet/10 kg twice weekly. Do not use with uterine/mammary disorders or before puberty; monitor for uterine and mammary progestogen effects.
Source:
König Singestar
Manufacturer material
Information published by the maker or a seller, such as a datasheet or product page. A medicines regulator has not necessarily reviewed it.
Singestar tablets - official product page and package leaflet
Official manufacturer instruction, 2012

Products are connected by name, active ingredients, or therapeutic group. They are not direct substitutes for one another.

Professional reference for veterinary professionals. Not advertising and not a substitute for the product label/SPC.

For veterinary professionals only. It does not replace clinical judgement or the product label; check the dose in the official label (SPC). vetman is not liable for harm caused by using this information.

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This reference is still growing. Missing a product? Let us know. · Report an error or request an addition · Updated: 21 Oct 2026

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The dose for the patient's weight, registration in Georgia and controlled status, right on the prescription.

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