TESTOSTERONE CYPIONATE, TESTOSTERONE ENANTHATE, TESTOSTERONE PROPRIONATE

Chemistry - The esterified compounds, testosterone cypionate, enanthate, and propionate areavailable commercially as injectable products. Testosterone cypionate occurs as an odorless tohaving a faint odor, creamy white to white, crystalline powder. It is insoluble in water, soluble invegetable oils, and freely soluble in alcohol. Testosterone cypionate has a melting range of 98°-104°C. It may also be known as testosterone cyclopentylpropionate.
Testosterone enanthate occurs as an odorless to having a faint odor, creamy white to white, crystalline powder. It is soluble in vegetable oils, insoluble in water and melts between 34-39°C.
Testosterone propionate occurs as odorless, creamy white to white, crystals or crystalline powder.
It is insoluble in water, freely soluble in alcohol and soluble in vegetable oils. Testosteronepropionate melts between 118-123°C.

Storage, Stability, Compatibility

The commercially available injectable preparations of testosterone cypionate, enanthate and propionate should be stored at room temperature; avoid freezing orexposing to temperatures greater than 40°C. If exposed to low temperature a precipitate may form, but should redissolve with shaking and rewarming. If a wet needle or syringe is used to draw up theparenteral solutions, cloudy solutions may result, but will not affect the drugs' potency.

Pharmacology - TESTOSTERONE CYPIONATE, TESTOSTERONE ENANTHATE, TESTOSTERONE PROPRIONATE

The principle endogenous androgenic steroid, testosterone is responsible formany secondary sex characteristic of the male as well as the maturation and growth of the malereproductive organs and increasing libido.
Testosterone has anabolic activity with resultant increased protein anabolism and decreased proteincatabolism. Testosterone causes nitrogen, sodium, potassium and phosphorus retention anddecreases the urinary excretion of calcium. Nitrogen balance is improved only when an adequateintake of both calories and protein occurs.
By stimulating erythropoeitic stimulating factor, testosterone can stimulate the production of redblood cells. Large doses of exogenous testosterone can inhibit spermatogenesis through a negativefeedback mechanism inhibiting lutenizing hormone (LH).
Testosterone may help maintain the normal urethral muscle tone and the integrity of the urethralmucosa in male dogs. It may also be necessary to prevent some types of dermatoses.
Uses, Indications - The use of injectable esters of testosterone in veterinary medicine is limitedprimarily to its use in dogs (and perhaps cats) for the treatment of testosterone-responsive urinaryincontinence in neutered males. Testosterone has been used to treat a rare form of dermatitis(exhibited by bilateral alopeci) in neutered male dogs. These drugs are also used in bovine medicineto produce an estrus-detector (teaser) animal in cull cows, heifers, steers.
The use of testosterone to increase libido, treat hypogonadism, aspermia and infertility in domesticanimals has been disappointing.

Pharmacokinetics - TESTOSTERONE CYPIONATE, TESTOSTERONE ENANTHATE, TESTOSTERONE PROPRIONATE

Orally administered testosterone is rapidly metabolized by the GI mucosa andthe liver (first-pass effect) and very little reaches the systemic circulation. The esterified compounds, testosterone enanthate and cypionate are less polar than testosterone and more slowly absorbedfrom lipid tissue after IM injection. The duration of action of these compounds may persist for 2-4weeks after IM injection. Testosterone propionate reportedly has a much shorter duration of actionthan either the enanthate or cypionate ester. Because absorption is dependent upon several factors(volume injected, perfusion, etc.), durations of action may be variable.
Testosterone is highly bound to a specific testosterone-estradiol globulin (98% in humans). Thequantity of this globulin determines the amount of drug that is in the free or bound form. The freeform concentration determines the plasma half-life of the hormone.
Testosterone is metabolized in the liver and is, with its metabolites, excreted in the urine (»90%)and the feces (»6%). The plasma half-life of testosterone has been reported to be between 10-100minutes in humans. The plasma half-life of testosterone cypionate has been reported to be 8 days.
Contraindications/Precautions - Testosterone therapy is contraindicated in patients with knownhypersensitivity to the drug or prostate carcinoma. It should be used with caution in patients withrenal, cardiac or hepatic dysfunction.

Adverse Effects, Warnings

Adverse effects are reportedly uncommon when injectable testosterone products are used in male dogs to treat hormone-responsive incontinence. Perianal adenomas, perineal hernias, prostatic disorders and behavior changes are all possible, however.
Polycythemia has been reported in humans receiving high dosages of testosterone. High dosages orchronic usage may result in oligospermia or infertility in intact males.
Overdosage - No specific information was located; refer to the Adverse effects section for furtherinformation.

Drug Interactions

Testosterone administered with oral anticoagulants may cause increasedbleeding in some patients. Diligent monitoring is necessary if patients are receiving androgens andoral anticoagulants. Anticoagulant dosage adjustments may be necessary when adding ordiscontinuing androgen therapy.
Diabetic patients receiving insulin may need dosage adjustments if androgen therapy is added ordiscontinued. Androgens may decrease blood glucose and decrease insulin requirements.
Androgens 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 testosterone therapy, but the clinical significance of this is probably notimportant. Androgen agents can decrease amounts of thyroxine-binding globulin and decreasetotal T4 concentrations and increase resin uptake of T3 and T4. Free thyroid hormones areunaltered and clinically, there is no evidence of dysfunction.
Both creatinine and creatine excretion can be decreased by testosterone. Testosterone 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.