WHY IS GROWTH HORMONE SO CONTROLLED?
I have read that elderly patients given growth hormone have improved muscle mass/fat ratios. Why is this agent so tightly controlled if the elderly as well as the obese might benefit from its effects?
—Craig Freyer, MD, Fort Worth, Tex.
Growth hormone has beneficial effects on body composition in the presence of documented growth hormone deficiency, and there is some limited experimental evidence that it may also be of use for dilated cardiomyopathy (N Engl J Med. 1996;334:809-814), although it is not recommended by the American College of Cardiology-American Heart Association task force for this purpose.
However, in otherwise healthy adults without deficiency, whether the benefits of growth hormone outweigh the risks is unclear, and it cannot be recommended (Br J Sports Med. 2003;37:100-105). Not only is it a very costly medication, but side effects can include peripheral edema, arthralgias, carpal tunnel syndrome, paresthesias, and worsening of glucose tolerance. In adults who have closed epiphyses, an excess of growth hormone can cause acromegaly.
Pseudotumor cerebri has been rarely reported secondary to growth hormone administration. There is also a theoretical increase in the risk of various neoplasms. If obtained on the black market, rather than being pharmaceutical grade recombinant growth hormone, it could be cadaveric, which could carry the risk of Creutzfeldt-Jakob disease. Furthermore, growth hormone can be a drug of abuse by athletes looking to improve their performance, which undoubtedly has led to some of the caution over prescribing. An excellent recent review of the topic is available (JAMA. 2005;294:2086-2090).
—Daniel G. Tobin, MD (100-3)