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4ml Bottle for Injection (25mg/ml)

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  • 4ml Bottle for Injection (25mg/ml) £61.00


Zycortal is a new treatment for Addison's disease (hypoadrenocorticism) in dogs. It is given by injection at approximately 1 month intervals. The precise dose and frequency is calculated by your vet in response to blood test results and clinical assessments made durong the initial phases of treatment.

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Medication Datasheets

4ml Bottle for Injection (25mg/ml)

Zycortal® 25 mg/ml Prolonged-release Suspension for Injection for Dogs

Qualitative and quantitative composition

Active substance: Desoxycortone pivalate 25 mg/ml

Excipient: Chlorocresol 1 mg/ml

Pharmaceutical form

Prolonged-release suspension for injection. Opaque white suspension.

Clinical particulars

Target species


Indications for use

For use as replacement therapy for mineralocorticoid deficiency in dogs with primary hypoadrenocorticism (Addison's disease).


Do not use in case of hypersensitivity to the active substance or to any of the excipients.

Special warnings for each target species

Before starting treatment with the veterinary medicinal product, it is important that Addison's disease has been definitively diagnosed. Any dog presenting with severe hypovolaemia, dehydration, pre-renal azotaemia and inadequate tissue perfusion (also known as 'Addisonian crisis') must be rehydrated with intravenous fluid (saline) therapy before starting treatment with the veterinary medicinal product.

Special precautions for use in animals

Use with caution in dogs with congestive heart disease, severe renal disease, primary hepatic failure or oedema.

Special precautions to be taken by the person administering the veterinary medicinal product to animals

Avoid contact with the eyes and skin. In case of accidental spillage onto the skin or eyes, wash the affected area with water. If irritation occurs, seek medical advice immediately and show the package leaflet or the label to the physician.

This product may cause pain and swelling at the injection site if accidentally self-administered.

This product may cause adverse effects on male reproductive organs and, as a result, fertility.

This product may cause adverse developmental effects on unborn children and neonates.

Pregnant and breast-feeding women should avoid administration of this product.

In case of accidental self-injection, seek medical advice immediately and show the package leaflet or the label to the physician.

Adverse reactions

In a clinical trial, very common adverse reactions were polydipsia and polyuria. Common reactions were inappropriate urination, lethargy, alopecia, panting, vomiting, decreased appetite, anorexia, decreased activity, depression, diarrhoea, polyphagia, shaking, tiredness and urinary tract infections. The frequency of adverse reactions is defined using the following convention:

- very common (more than 1 in 10 animals displaying adverse reaction(s) during the course of one treatment)

- common (more than 1 but less than 10 animals in 100 animals)

Use during pregnancy, lactation or lay

The safety of the veterinary medicinal product has not been established during breeding, pregnancy or lactation. Therefore, use only according to the benefit/risk assessment by the responsible veterinarian.


Use with caution when administering Zycortal concurrently with medicinal products which affect either serum sodium or potassium concentrations, or cellular transportation of sodium or potassium, for example: trimethoprim, amphotericin B, digoxin or insulin.

Amounts to be administered and administration route

Subcutaneous use.

Prior to use, gently shake the vial to resuspend the product.

Use an appropriately graduated syringe to accurately administer the required dose volume. This is particularly important when injecting small volumes.

Zycortal replaces the mineralocorticoid hormones only. Dogs with combined glucocorticoid and mineralocorticoid deficiency should also receive a glucocorticoid such as prednisolone in accordance with standard texts.

Zycortal is intended for long term administration at intervals and doses dependent upon individual response. Tailor the dose of Zycortal and the concurrently administered glucocorticoid replacement therapy to the individual dog based on clinical response and normalization of Na+ and K+ serum concentrations.

Initial dose of Zycortal:

The initial dose is 2.2 mg/kg body weight, administered by subcutaneous injection.

Interim monitoring visit:

Re-evaluate the dog and measure the serum sodium/potassium ratio (Na+/K+ ratio) approximately 10 days after the first dose (which is the time to maximum concentration (Tmax) of desoxycortone). If the dog's clinical signs have worsened or not resolved, adjust the dose of glucocorticoid and/or investigate other causes of the clinical signs.

Second dose of Zycortal:

At approximately 25 days after the first dose, re-evaluate the dog and measure the Na+/K+ ratio.

- If the dog is both clinically normal and has a normal Na+/K+ ratio (i.e. 27 to 32) on Day 25, adjust the dose based on the Day 10 Na+/K+ ratio using the guidelines in Table 1.

- If the dog is clinically normal and has a Na+/K+ ratio >32 on Day 25, either adjust the dose based on the Day 10 Na+/K+ ratio according to Table 1 or delay the dose (see Prolonging the dosing interval).

- If the dog is either not clinically normal or if the Na+/K+ ratio is abnormal on Day 25, adjust the dose of glucocorticoid or Zycortal (see Subsequent doses and long term management).

Table 1: Day 25: Administering the Second Dose of Zycortal

Prolonging the dosing interval:

If the dog is clinically normal and the Day 25 Na+/K+ ratio is >32, it is possible to prolong the dosing interval instead of adjusting the dose as described in Table 1. Evaluate the electrolytes every 5-9 days until the Na+/K+ ratio is <32, and then administer 2.2 mg/kg of Zycortal.

Subsequent doses and long term management:

Once the optimal dose and dosing interval have been determined, maintain the same regimen. If the dog develops abnormal clinical signs or Na+ or K+ ratio serum concentrations, use the following guidelines for subsequent doses:

- Clinical signs of polyuria/polydipsia: Decrease the glucocorticoid dose first. If the polyuria/polydipsia persists and the Na+/K+ ratio is >32, then decrease the dose of Zycortal without changing the dosing interval.

- Clinical signs of depression, lethargy, vomiting, diarrhoea or weakness: Increase the glucocortinoid dose.

- Hyperkalaemia, hyponatremia or Na+/K+ ratio <27: Decrease the Zycortal dosing interval by 2-3 days or increase the dose.

- Hypokalaemia, hypernatremia or Na+/K+ ratio >32: Decrease the Zycortal dose.

Prior to a stressful situation, consider temporarily increasing the dose of glucocorticoid.

In the clinical trial, the mean final dose of desoxycortone pivalate was 1.9 mg/kg (range 1.2-2.5 mg/kg) and the mean final dosing interval was 38.7 ± 12.7 days (range 20-99 days) with the majority of dogs having a dosing interval between 20 and 46 days.


When given to dogs at three to five times the recommended dose, injection site reactions characterised by erythema and oedema occurred.

As expected from the pharmacodynamic effects, escalating doses of desoxycortone are associated with a dose-related trend for increased serum sodium, and decreased blood urea nitrogen, serum potassium and urine specific gravity. Polyuria and polydipsia may be observed.

Hypertension has been observed in dogs receiving 20 mg/kg of desoxycortone pivalate.

There is no specific antidote. In case of signs of overdose, the dog should be treated symptomatically, and subsequent doses reduced.

Pharmacological particulars

Pharmacotherapeutic group: Corticosteroids for systemic use, mineralocorticoids

ATCvet code: QH02AA03

Pharmacodynamic properties

Desoxycortone is a corticosteroid with primarily mineralocorticoid activity, similar to aldosterone. In the kidney, desoxycortone causes sodium and chloride ion retention, and hydrogen and potassium ion excretion, creating an osmotic gradient. The osmotic gradient promotes water absorption from the renal tubules resulting in increased extracellular fluid volume, leading to blood volume expansion, improved venous return to the heart, and increased cardiac output.

Pharmacokinetic properties

After subcutaneous administration of desoxycortone pivalate at a dosage of 11 mg/kg body weight (five times the recommended dosage), the plasma half-life (mean ± standard deviation) is approximately 17 ± 7 days, with a maximum concentration (Cmax) of 13.2 ± 5 ng/ml, and time to maximum concentration (Tmax) of 10 ± 3.5 days.

Pharmaceutical particulars


In the absence of compatibility studies, this veterinary medicinal product must not be mixed with other veterinary medicinal products.

Shelf life

Shelf life of the veterinary medicinal product as packaged for sale: 3 years

Shelf life after first opening the immediate packaging: 120 days

Special precautions for storage

Do not store above 30°C.

Do not freeze.

Immediate packaging

Type I glass vial (containing 4 ml) with a coated chlorobutyl rubber stopper and aluminium seal with a plastic flip-off cap.

Pack size of 1.


Any unused veterinary medicinal product or waste materials derived from such veterinary medicinal products should be disposed of in accordance with local requirements.

Marketing Authorisation Holder (if different from distributor)

Dechra Limited, Snaygill Industrial Estate, Keighley Road, Skipton, North Yorkshire, BD23 2RW, United Kingdom.

Marketing Authorisation Number


Date of the first authorisation or date of renewal

6 November 2015

Date of revision of the text

November 2015

Any other information

For animal treatment only. To be supplied only on veterinary prescription. Keep out of the sight and reach of children.

Legal category

Delivery Information

How quickly do you deliver?

Under almost all products on our website is an Estimated dispatch time, check this for a delivery prediction specific to the item you are looking to purchase. These badges are updated live based on the stock levels we have and also those of our suppliers - so are usually very accurate, but cannot be guaranteed. In more general terms, we aim to dispatch all orders within 1 working day of receiving payment (and a prescription if required). If we cannot do so within 3 working days we will contact you by email.

What do you charge for delivery?

For UK delivery, we charge the following:

Order Total Weight Delivery
£0-£28.99 Under 2kg £2.99
2kg+ £4.99
£29-£38.99 Under 2kg Free
2kg+ £4.99
£39+ Under 2kg Free
2kg+ Free

Prices quoted are for delivery to all parts of mainland UK except certain Scottish postcodes (where the price is higher for items sent by courier. Delivery of food abroad (including Channel Islands, N. Ireland and other islands around the UK) is charged at a higher price and free delivery is not available. Temperature controlled products are also not always subject to the standard and/or free delivery options.

For full information on our delivery charges, including prices on heavy deliveries to Scotland and abroad, see our delivery information page.

We can deliver most items to all around the world, but prices do vary. To find the exact cost of shipping your item, and to see all options available, follow these steps:

  1. Put the items you wish to order in your basket
  2. Proceed to checkout and enter your delivery address, including country
  3. Delivery information including price will automatically update to what is available to you

Delivery of aerosols

Due to restrictions aerosols can't be sent by Royal Mail. We appreciate your understanding.

Delivery of temperature controlled items

Some products, such as non-ambient items and frozen food, need to be delivered in insulated packaging to prevent them from getting too warm (or too cold) during transit from us to you. Purchasing any of these items in your order will result in a £1.99 charge being added to the total to cover the high cost of the insulated packaging materials. You only pay the £1.99 once per order, regardless of how many temperature controlled items you purchase in that order.

How do I cancel or return an order?

Please call us as soon as possible if you need to amend or cancel an order on 01582 842096. If your order has been processed for dispatch we will be unable to cancel or amend the order. You will however be able to return your product for a full refund*.

To return an item, you must contact us by phone or email to arrange this BEFORE posting any product back to us. We will explain the process at this stage for you.

*For full details on returns, see our terms and conditions page.

Reviews (46)

Q & A

Below are some recent questions we've received regarding Zycortal, including answers from our team.

16 May 2017 at 2:58pm

Shelf life

Abigail Newell

  • VioVet customer since 2009
  • From: Hertfordshire, United Kingdom

Can you tell me the shelf life of a 4ml bottle of Zycortal please. Thank you.

  • Veterinary Advisor

Shelf life of the veterinary medicinal product as packaged for sale: 3 years

Shelf life after first opening the immediate packaging: 120 days

8 June 2016 at 12:29am

Syringe and needle

Cathy Forrester

  • VioVet customer since 2016
  • From: Kent, United Kingdom

Does the syringe and needle come with it or do I need to buy them separately. Thank u.

Also can you tell me how I go about sending the pricrption. Can I send it by recorded delivery and where do I send the pricrption to.

Sorry this is the first time I'm ordering a pricrption drug online so I'm not quit sure how to go about it.


  • Non-Executive Director

This product is just the liquid for injection, there are no syringes or needles supplied. It is normally administered by a vet who will have such things to hand anyway. If your vet considers that you can administer this yourself, he/she should give you full instruction on how to do this. Some vets will provide the prescription so that you can buy the medication more economically, then you can take it to the veterinary premises and a nurse or vet can inject it for you for a nominal fee. This depends on the individual vets. If you are to inject this yourself, you can buy syringes and needles from the website. (A 21g x 5/8" needle is normally used on a 1ml or 2ml syringe, depending on the dose to be given.) Personally I would be very wary of you giving the injection yourself unless you have proper training or experience to do this, but that decision is down to the vet writing out the prescription. Some people are giving the injections very successfully thensleves (just as they are for diabetic dogs).

Once you have a written prescription from your vet, you can scan it in and email it to us, or take a photo of it with your mobile phone and email that to us.You can fax it or upload it to the website when placing the order, or you can post it to us. The possibilities are endless! Details are all on the website. When we receive a copy of the prescription we might well ring your vet just to check that all is well before we supply against it. Your simplest option is to email it to us using [email protected]