Hormone Therapy Drugs
Drugs used in hormone therapy for prostate cancer inhibit the action or block the production of testosterone and other male hormones. This section discusses LHRH analogs, total androgen blockade and their advantages, disadvantages and side effects; estrogen therapy; testing during and after hormone therapy; intermittent hormone therapy; and adjuvant hormone therapy.
The most common drugs used in hormone therapy are called LHRH analogs. LHRH is the acronym for luteinizing hormone-releasing hormone, a hormone produced by the brain, whose purpose is to regulate testosterone production. An analog is a synthetic chemical or drug that behaves similarly to a normal chemical in the body. So an LHRH analog is a drug that behaves very much like LHRH; that is, it regulates the production of testosterone. However, when used on a long-term basis, LHRH analogs suppress testosterone production. LHRH analogs are the chemical equivalent of orchiectomy, resulting in a very low level of testosterone in the body.
LHRH is the first in a series of steps leading to the production of testosterone by the testicles. The brain monitors and regulates testosterone levels in the blood. When the brain detects that testosterone levels have fallen below normal, the brain releases a sequence of hormones, which ultimately signal the testicles to produce more testosterone. Conversely, when the brain detects that the body is producing too much testosterone, it stops sending the signals that stimulate testosterone production.
In the first few days of treatment, LHRH analogs send signals that cause the testicles to increase testosterone production. The brain stops sending signals to stimulate hormone production. This results in low levels of testosterone in the body, similar to those achieved with orchiectomy.
The two most common LHRH drugs are leuprolide acetate (Lupron) and goserelin acetate (Zoladex). Lupron is administered by injection into the muscle of the buttocks monthly, every three months, or every four months. Zoladex comes in pellet form and is injected under the skin of the abdomen monthly or every three months. Lupron and Zoladex injections are administered in a doctor’s office. Men who use LHRH analogs for treatment of advanced disease do so for the rest of their lives.
Advantages of LHRH analogs
LHRH analogs perform the same function as orchiectomy without surgery. The patient needs to get an injection only once every month, three months, or four months.
Disadvantages of LHRH analogs
The shots are required every three to four months and are very expensive. Health insurance may not cover the total cost.