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Ovarid Tablets for Dogs & Cats

  • Clearance 5mg » Priced per Tablet (Expires Jan 2017) £0.81


Ovarid tablets contain a progestagen-like hormone which has anti-oestrogenic activity. Ovarid is used in dogs and cats as a hormone therapy. It can be used to suppress coming into season (oestrus) for queens and bitches and to reduce undesirable behaviour in male dogs.
Ovarid has also been found to be helpful in some types of skin disorder in cats, including Miliary Dermatitis and Eosinophilic Granuloma.


Buff coloured, slightly speckled, biconvex uncoated tablets with a break line on one surface. Each tablet contains Megestrol Acetate BP in a dried yeast base. Two strengths are available: 20 mg tablets and 5 mg tablets.



Megestrol acetate is a potent progestagen with marked anti-oestrogenic properties. It is recommended for administration by the oral route in bitches for the postponement or prevention of oestrus and the treatment of hypersexuality which may be manifest as undesirable behaviour in male dogs.

In cats it is recommended for prevention or postponement of oestrus and the treatment of miliary dermatitis and eosinophilic granulomata.

Postponement of oestrus (Bitches)

Ovarid Tablets may be used to postpone an anticipated oestrus. Following the recommended course it is not possible to state when the next oestrus period will occur, with any degree of accuracy, as this will depend on the stage of an-oestrus when the tablets were administered. It is most likely, however, that it will appear some three months later. It is unlikely that oestrus will be delayed by more than six months.

Prevention of oestrus (suppression of heat) (Bitches)

When the tablets are used by the recommended method for the prevention of oestrus, the signs of pro-oestrus usually disappear in two to three days and the subsequent oestrus normally occurs four to six weeks earlier than would have been the case had medication not been given.

Oestrus control in cats

Oestrus can be prevented or postponed by selecting an appropriate dose regime. The occurrence of the next oestrus following treatment may be variable because the cat is seasonally polyoestrus and ovulation does not occur spontaneously.

However, the next call after a prevention course given during the breeding season will probably occur a few days later than normally expected – on average about four weeks after the last dose is given. Queens given a correctly timed postponement course will not call whilst they are receiving the tablets.

Miliary eczema in cats

Field experience with Ovarid has shown it to be very successful in the treatment of miliary eczema. A clinical response can be expected in most cases within the first few days of commencing treatment.

Eosinophilic granuloma (rodent ulcer) in cats

Clinical experience has shown that Ovarid can be beneficial in this condition.

Undesirable behaviour in dogs

Trials have shown that Ovarid is an effective treatment in 75% of dogs exhibiting the following undesirable behaviour:

-Aggression – either dominant or submissive (fear-induced)


-Territory marking by urination




Dosage and administration

Postponement of oestrus (Bitches)

0.5 mg/kg daily for a maximum period of forty days. The course of tablets should commence preferably fourteen but at least seven days before the effect is required. A series of postponement courses may be given provided the bitch is not medicated more than twice in any 12 month period.

Prevention of oestrus (suppression of heat) (Bitches)

Normal dosage regimen: 2 mg/kg daily for eight days. The course of tablets should commence at the onset of pro-oestrus as indicated by the presence of both haemorrhage and vulval swelling. The stage of the oestrus cycle may be confirmed by the examination of vaginal smears.

Extended dosage regimen: 2 mg/kg daily for four days followed by 0.5 mg/kg daily for 16 days.

The use of this prolonged prevention course is advised in first season bitches, and may also be beneficial in bitches with a history of false pregnancy, in some cases where other abnormalities of the oestrus cycle are known to occur and when the animal to be medicated is housed with other bitches.

Oestrus control in cats

1.Postponement of oestrus - 2.5 mg per cat once weekly for up to 30 weeks. Dosage should commence in anoestrus (the non-breeding season).

2.Prevention of oestrus - 5 mg per cat daily for three days commencing as soon as the signs of calling are seen.

Treatment of miliary eczema (miliary dermatitis) and eosinophilic granuloma (rodent ulcer) in cats

The recommended dosage is 2.5 to 5 mg per cat every two to three days until the lesions begin to regress then once weekly until a satisfactory response is obtained. In some cases it may be necessary to give a maintenance dosage of 2.5 mg per cat weekly or fortnightly to prevent recurrence of the condition. Alternatively, repeat courses of treatment may be given as required.

Undesirable behaviour in dogs

The dosage should be adjusted according to response and the following is offered as a guide:

Initial Dosing

Subsequent Dosing

2 mg/kg daily for 7 days

Improved - 1 mg/kg daily for 14 days

Not Improved - 4mg/kg daily for 7days

Improved - 1 mg/kg for 14 days

Not Improved - cease treatment

In a minority of animals, it may be necessary to prescribe a low maintenance dose on a once weekly basis or to give repeat short courses of medication as required.

Treatment with Ovarid in conjunction with re-training appears to increase the level of success in cases of undesirable behaviour.

Contra-indications, warnings, etc

It must be remembered that progestagens, like other synthetic hormones, should always be used with care. This is particularly so in bitches treated at their first oestrus. Owners should be advised that this class of bitch, and a small proportion of others which have abnormal oestrus cycles, may show excessive libido, or oestrus may return earlier than expected, because of difficulties which may be encountered with the timing of administration.

Apart from these considerations experience has shown that, when used correctly, Ovarid Tablets do not produce undesirable side effects since oral administration allows the duration of effect to be more accurately controlled than is the case with depot injections.

In the prevention of oestrus in bitches, the timing of administration is of great importance if the best results are to be obtained. If Ovarid Tablets are given once ovulation has occurred, they may aid conception.

Ovarid is not recommended in diabetic animals.

Occasionally, lethargy and increased appetite with consequent weight gain may be seen in treated animals.

As with all progestagens there is the possibility of endometrial changes. However, at the recommended doses of Ovarid there should be no adverse effects.

Very occasionally, following the long-term use of megestrol acetate in cats to prevent the recurrence of miliary eczema, mammary hypertrophy may occur. This effect is quite distinct from mammary neoplasia and may regress on cessation of dosing. In such cases medication should be withdrawn.

Male dogs intended for breeding should not be treated with Ovarid.

Dispose of used packaging in the household refuse. Unused product should be returned to the veterinary surgeon.

Pharmaceutical precautions


Legal category


Packaging Quantities

200x5 mg tablets.

200x20 mg tablets.

Further information

Progestagens may inhibit parturition. Therefore, if Ovarid is given (to cats) during pregnancy, it should be withdrawn 2 to 3 weeks prior to parturition. (Ovarid is not recommended for use in pregnant bitches.)

Experience has shown that bitches conceive normally at the heat following the withdrawal of megestrol acetate. Ovarid can be given to bitches to prevent the oestrus which occurs after cessation of dosing with a postponement course.

In breeding queens it is advisable that mating should be allowed at the second or subsequent call rather than the first call after cessation of dosing.

Marketing authorisation number

Vm 05653/4161 5mg Tablets.

Vm05653/4160 20mg Tablets.

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Questions & Answers for Ovarid Tablets for Dogs & Cats

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Use of Ovarid

16th Dec 2013
Julie Ripley

I have used Ovarid for my bengal queen for 15 weeks, I stopped using it on the 7th December 2012 she started to call on Wednesday evening this week after stopping using Ovarid, is it safe to mate her this season or should I wait until next time? This is her first season after using ovarid. She is two years old and has had one litter a year ago.

  • Website Content Developer

It is recommended to wait until the second (or subsequent) season before mating, once Ovarid has been stopped. It might work OK at the first, but the chances of a successful mating are improved if you do not mate her this time.