Testosterone is an endogenous androgen supplied medicinally in ester formulations that prolong delivery. Veterinary applications include selected hormone-responsive disorders in neutered males and historical androgen-replacement or anabolic use. Testosterone cypionate and propionate differ in release characteristics. Clinical benefit depends on the disorder and the patient’s hormonal state.
Group
Androgen and anabolic hormone
Mechanism of Action
Testosterone released from its ester activates intracellular androgen receptors and changes transcription in responsive tissues. Effects include regulation of reproductive tissues, protein synthesis and androgen-dependent functions. In selected urinary disorders, androgenic effects can support urethral tissue function and closure pressure. Some tissue actions depend on conversion to dihydrotestosterone or estradiol.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Androgen support with cypionate | 1–2 mg/kg | IM | Every 336–672 h | Do not use in: Pregnancy, Animals intended for food; Cypionate ester specifically; every 2-4 weeks. |
| Androgen support with propionate | Reference only | IM | Do not use in: Pregnancy, Animals intended for food; Propionate ester 0.5-1 mg/kg IM two or three times per week. Exact evenly spaced hourly schedule is not specified. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Androgen support with cypionate | 1–2 mg/kg | IM | Every 336–672 h | Do not use in: Pregnancy, Animals intended for food; Cypionate ester specifically; every 2-4 weeks. |
| Androgen support with propionate | Reference only | IM | Do not use in: Pregnancy, Animals intended for food; Propionate ester 0.5-1 mg/kg IM two or three times per week. Exact evenly spaced hourly schedule is not specified. |
Indications
- Treatment of selected testosterone-responsive urinary incontinence in neutered male dogs.
- Historical treatment of selected androgen-responsive alopecia in neutered male dogs, with limited clinical evidence.
- Selected androgen replacement for clinically supported deficiency, with variable response according to the reproductive disorder.
- Historical anabolic support in selected debilitated veterinary patients, with limited evidence of clinical benefit.
Contraindications
- Pregnancy
- Hepatic disease requires caution; reported guidance excludes injections in animals intended for food.
Adverse effects
- Masculinization, prostatic hyperplasia and hepatic effects.
Toxicity
Specific acute-overdose information is limited; excessive androgenic effects and hepatic or fluid-retention complications require assessment.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Testosterone cypionate 100 mg/mL | Injection | 100 mg / mL | IM |
| Testosterone cypionate 200 mg/mL | Injection | 200 mg / mL | IM |
| Testosterone propionate 100 mg/mL | Injection | 100 mg / mL | IM |
Monitoring and Administration
Monitor hepatic enzymes and androgenic effects. Veterinary clinical efficacy is not well established.
Oil formulations must be protected from heat, light and freezing.
Male canine urinary-incontinence reports: cypionate 2.2 mg/kg IM every 4-8 weeks, or 200 mg IM every 30 days; propionate 2-2.2 mg/kg IM/SC every 2-3 days or three times weekly. Feline propionate 5-10 mg IM as needed and mixed-ester infertility 0.1-1 mg IM/SC every 2-3 days for 3-5 injections are separate ester protocols.
Estrus control and pseudopregnancy reports use cypionate or enanthate rather than testosterone base. Bovine teaser-animal protocols use staged propionate/enanthate loading and large depot doses; they are not routine replacement regimens and require food-animal authorization assessment.