What is stanozolol?
Stanozolol (brand name: Winstrol®) is an anabolic steroid previously used to treat poor appetite, anemia, and other health issues. Studies are limited, however, and use is uncommon because it is not available in the United States as a manufactured medication; it is only available through compounding pharmacies.
A recent study shows it may be effective in treating tracheal collapse in dogs. It is used in pet animals only; it is not used in farmed animals. This medication is considered a controlled substance.
The commercially produced form was FDA-approved for dogs, cats, and horses; however, its current use as a compounded medication in dogs, cats, horses, birds, reptiles, ferrets, rabbits, and other small mammals to treat weight loss, anemia, poor appetite, and other issues is off label (extra label).
Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.
How is stanozolol given?
- Stanozolol is given by mouth. Your veterinarian may recommend stanozolol be compounded in the form of a tablet, capsule, or liquid.
- Measure liquid forms carefully.
- It may be given with or without food; however, if vomiting occurs when dosed on an empty stomach, give future doses with food.
- DO NOT handle this medication if you are pregnant. If it is necessary, wear gloves and wash your hands immediately after administration.
This medication should take effect within 1 to 2 hours; however, effects may not be noted outwardly, so laboratory tests may be needed to evaluate this medication’s effectiveness.
What if I miss giving my pet the medication?
If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.
Are there any potential side effects?
Side effects of stanozolol are not well known in animals, as studies are limited. Side effects may include:
- Behavior changes, including sexual behaviors
- Water retention
- Limb swelling
- Prevention of heat cycles
Serious adverse reactions may occur. If any of the following signs develop, stop giving stanozolol and contact your veterinarian immediately:
- Yellowing of the skin, gums, or eyes
- Lack of appetite
- Severe vomiting
- Weakness
- Tiredness
Drug sensitivities can develop over time, with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment (e.g., irregular breathing, rash, fever, puffiness and swelling around the face) and notify your veterinarian if you have any concerns.
Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This moderate-acting medication should stop working in a few days, although effects can be longer in pets with liver or kidney disease.
Are there any risk factors for this medication?
DO NOT USE stanozolol in:
- Pets that are allergic to it
- Pets that are pregnant, breeding, or nursing
USE WITH CAUTION in:
- Pets with liver, heart, prostate, or kidney disease
- Pets with high blood calcium
- Pets with diabetes insipidus (different than diabetes mellitus)
- Cats
Are there any drug interactions I should be aware of?
The following medications should be used with caution when given with stanozolol:
- Anticoagulants
- Corticosteroids
- Insulin
Stanozolol also interacts with the following lab tests:
- Thyroid
- Creatinine
- Creatine
- Sugar/glucose
- Liver function
Be sure to tell your veterinarian about any medications (including vitamins, supplements, and herbal therapies) that your pet is taking before starting any treatment.
Is any monitoring needed with this medication?
- Your veterinarian may monitor hydration, electrolyte status, liver enzymes, blood cell counts, weight and appetite.
- Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
- At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.
How do I store stanozolol?
- Store compounded forms of this medication according to the label.
- Store at room temperature and protect from light.
- Keep the container out of reach of children and pets. 
Stanozolol is a controlled substance, which means it has been designated by the US Drug Enforcement Administration (DEA) as having a potential for diversion to people other than the patient it was prescribed for. Use of a controlled substance in any person or animal other than that for which it is prescribed is illegal. Therefore, this medication should be stored in a locked cabinet or safe that cannot be easily moved, with access limited to only those that need to administer the medication. Monitor the amount of medication remaining to ensure the expected amount is present. 
What should I do in case of emergency?
If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms.
