Elephant Formulary

© 2003-17 Susan K. Mikota DVM and Donald C. Plumb, Pharm.D. Published by
Elephant Care International

Disclaimer: the information on this page is used entirely at the reader's discretion, and is made available on the express condition that no liability, expressed or implied, is accepted by the authors or publisher for the accuracy, content, or use thereof.


Boldenone Undecylenate

Elephant specific information, if available, is in blue.

Chemistry – An injectable anabolic steroid derived from testosterone, boldenone undecylenate  has a chemical name of 17 beta-hydroxyandrosta-1,4-dien-3-one. The commercially available product is in a sesame oil vehicle. It may also be known by the name boldenone undecenoate  or in the U.K. by the trade name, Vebonol®  (Ciba-Geigy).


Storage/Stability/Compatibility – Boldenone injection should be stored at room temperature; avoid freezing. Because it is in an oil vehicle, it should not be physically mixed with any other medications.


Pharmacology – In the presence of adequate protein and calories, anabolic steroids promote body tissue building processes and can reverse catabolism. As these agents are either derived from or are closely related to testosterone, the anabolics have varying degrees of androgenic effects. Endogenous testosterone release may be suppressed by inhibiting lutenizing hormone (LH). Large doses can impede spermatogenesis by negative feedback inhibition of FSH.


Anabolic steroids can also stimulate erythropoiesis. The mechanism for this effect may occur by stimulating erythropoeitic stimulating factor. Anabolics can cause nitrogen, sodium, potassium and phosphorus retention and decrease the urinary excretion of calcium.


Uses/Indications – Boldenone is labeled for use as adjunctive therapy “… as an aid for treating debilitated horses when an improvement in weight, haircoat, or general physical condition is desired” (Equipoise®  package insert—Solvay).


Pharmacokinetics – No specific information was located for this agent. It is considered to be a long-acting anabolic, with effects persisting for up to 8 weeks. It is unknown if the anabolic agents cross into milk.


Contraindications/Precautions – The manufacturer (Solvay) recommends not using the drug on stallions or pregnant mares. Other clinicians state the that anabolic steroids should not be used in either stallions or non-pregnant mares intended for reproduction. Boldenone should not be ad­ministered to horses intended for food purposes.


In humans, anabolic agents are also contraindicated in patients with hepatic dysfunction, hypercalcemia, patients with a history of myocardial infarction (can cause hypercholesterolemia), pi­tuitary insufficiency, prostate carcinoma, in selected patients with breast carcinoma, benign prostatic hypertrophy and during the nephrotic stage of nephritis.


The anabolic agents are category X (risk of use outweighs any possible benefit) agents for use in pregnancy and are contraindicated because of possible fetal masculinization.


Adverse Effects/Warnings – In the manufacturer’s (Equipoise® —Solvay) package insert, only androgenic (overaggressiveness) effects are listed. However, in work reported in both stallions and mares (Squires and McKinnon 1987), boldenone caused a detrimental effect in testis size, sperm production and quality in stallions. In mares, the drug caused fewer total and large follicles, smaller ovaries, increased clitoral size, shortened estrus duration, reduced pregnancy rates and severely altered sexual behavior. Although not reported in horses, anabolic steroids have the potential to cause hepatic toxicity.


Overdosage – No information was located for this specific agent. In humans, sodium and water retention can occur after overdosage of anabolic steroids. It is suggested to treat supportively and monitor liver function should an inadvertent overdose be administered.


Drug Interactions – No drug interactions were located for boldenone specifically. Anabolic agents as a class may potentiate the effects of anticoagulants. Monitoring of PT’s and dosage adjustment, if necessary, of the anticoagulant are recommended.


Diabetic patients receiving insulin, may need dosage adjustments if anabolic therapy is added or discontinued. Anabolics may decrease blood glucose and decrease insulin requirements. Anabolics may enhance the edema that can be associated with ACTH or adrenal steroid therapy.


Drug/Laboratory Interactions – Concentrations of protein bound iodine (PBI) can be decreased in patients receiving androgen/anabolic therapy, but the clinical significance of this is probably not important. Androgen/anabolic agents can decrease amounts of thyroxine-binding globulin and decrease total T4 concentrations and increase resin uptake of T3 and T4. Free thyroid hormones are unaltered and clinically, there is no evidence of dysfunction. Both creatinine and creatine excretion can be decreased by anabolic steroids. Anabolic steroids can increase the urinary excretion of 17-ketosteroids. Androgenic/anabolic steroids may alter blood glucose levels. Androgenic/anabolic steroids may suppress clotting factors II, V, VII, and X. Anabolic agents can affect liver function tests (BSP retention, SGOT, SGPT, bilirubin, and alkaline phosphatase).


Doses –


a)   1.1 mg/kg IM; may repeat in 3 week intervals (most horses will respond with one or two treatments) (Package Insert; Equipoise®—Solvay)

b)   1 mg/kg IM; repeated at 3 week intervals (Robinson 1987)



Monitoring Parameters –

1)   Androgenic side effects

2)   Fluid and electrolyte status, if indicated

3)   Liver function tests if indicated

4)   Red blood cell count, indices, if indicated

5)   Weight, appetite



Client Information – Because of the potential for abuse of anabolic steroids by humans, many states have included, or are considering including this agent as a controlled drug. It should be kept in a secure area and out of the reach of children.


Dosage Forms/Preparations/FDA Approval Status/Withholding Times –


Veterinary-Approved Products:

Boldenone Undecylenate for Injection 25 mg/ml in 10 ml vials; 50 mg/ml in 10 ml & 50 ml vials; Equipoise®  (Fort Dodge); (Rx)  Approved for use in horses not to be used for food.


 Human-Approved Products: None