Cardiovascular – cardiomegaly, hypo/hypertension.
Endocrine/metabolic – hypopituitarism, hypothyroidism, disturbances in maintenance of blood glucose levels.
Gastrointestinal – potential for increased feed and fluid intake.
Hemic/lymphatic/immune – injection site reactions, potential neutralizing antibody formation.
Musculoskeletal – potential for increased muscle mass and weight gain, stimulation of skeletal growth. Potential for increased osteoarthritis.
Renal/urologic – fluid retention.
Reproductive – potential for mammary stimulation at high doses.
Skin/exocrine – injection site reactions, excessive sweating.
Potential for increased illicit use in performance horses.
Risk Factors
Higher potential for use in performance horses
Incomplete medical records and failure to disclose administrations by owners/trainers.
Historical Findings
History of use of GH substances. Owner or trainer may be reluctant to disclose.
History of use of other performance‐enhancing drugs with similar desired effects such as anabolic steroids, selective androgen receptor modulators and beta‐agonists.
Performance supplement use.
Clinical exam may not suggest exposure.
Administration of other pharmaceutical agents such as anabolic steroids.
Stimulation of hypothalamic–pituitary axis by other environmental or pharmaceutical agents.
Evaluate for pituitary gland disorders or neoplasms.
Administration of IGF‐1.
IGF1 levels can be determined from blood samples.
Hyperglycemia or hypoglycemia depending upon time course.
Detection of parent compounds (GH or its secretagogues) is not a routine clinical diagnostic test.
Potential to send samples to specialized laboratories for LC‐MS testing.
Objectives of treatment are to prevent further exposure to compounds and provide symptomatic treatments.
Detoxification
No well‐characterized treatment strategies. Detoxification strategy based upon reducing potential for exposure.
Antidotes
Somatostatin analogs (octreotide and lareotide) have strong suppression on GH production.
Appropriate Health Care
Monitor blood glucose levels.
CBC and biochemistry panel to evaluate hydration status and overall health.
Evaluate thyroid and parathyroid levels.
Potential for increased urinary excretion of inorganic phosphorus and calcium.
Hepatic function panel to evaluate abnormal alkaline phosphatase.
Evaluate for elevated IGF‐1 in blood sample.
Precautions/Interactions
Decreased insulin sensitivity and glucose intolerance.
Avoid co‐administration with CYP450 substrates.
Decreased efficacy of corticosteroids.
Client Education
Educate client on the potential for exposure from performance‐enhancing supplements marketed on the internet.
Prevention/Avoidance
Remove compounds from the environment.
Possible Complications
Contaminants or adulterants found in supplements.
Unknown exposure to other related compounds.
Expected Course and Prognosis
Compounds are relatively quickly eliminated following administration.
Effects are time‐ and dose‐dependent, with lower dosages and duration of exposure having better prognosis.
Abbreviations
See Appendix 1 for a complete list.
Suggested Reading
1 Sigalos JT, Patuszak AW. The safety and efficacy
