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Dostinex and Heart
Valves For Prostate Cancer Patients
March 25, 2007
Last issue we mentioned a
recent paper in the New England Journal of Medicine that reported
heart problems in patients on Dostinex (cabergoline). We have
now had time to review this issue and can provide some perspective
on this topic.
Dostinex is a member of a class of drugs based on ergot, which
mimics the hormone dopamine. A physician prescribes these drugs
when he wishes to enhance dopamine-like effects. This situation
arises most commonly in treating Parkinson’s disease, which
is characterized by dopamine deficiency. By administering a drug
that duplicates dopamine’s effects, many of the symptoms
of Parkinson’s can be alleviated.
Another movement disorder called restless legs is also improved
by increasing dopamine-like effects with Dostinex and other ergot-based
drugs. Dopamine and drugs like Dostinex block the formation of
a hormone called prolactin. Some brain tumors make excess prolactin,
and Dostinex is commonly used to reduce the symptoms of these
tumors via its ability to block prolactin.
Prolactin also plays a role in normal human biology. Breast enlargement
during puberty and lactation at the end of pregnancy requires
the joint action of prolactin and estrogen. So, as you might
anticipate, Dostinex and related drugs can be used to stop milk
production in women who do not want to nurse.
Breast enlargement is a side effect of several hormonal treatments
for prostate cancer. This side effect can be particularly prominent
when Casodex is used as a single agent or when men are treated
with estrogen. Dostinex and other ergot-based dopamine blockers
have proved useful in lessening the severity of breast enlargement
under these treatment conditions.
Normal prostate cells and prostate cancer cells have receptors
for prolactin. The presence of prolactin appears to play a role
in preparing the prostate gland to respond to the surge of testosterone
that happens at the start of puberty in men and to enhance normal
response of the gland to testosterone later in life. Abnormally
high exposure to prolactin and estrogen early in life cause a
dramatic increase in prostatitis in adult rodents. There is some
thought that prolactin, with or without estrogen, may play a
role in some cases of chronic prostatitis in men as well. In
the laboratory, you can stimulate prostate cancer growth by adding
prolactin. Based on these factors, Dostinex and other ergot-based
dopamine agonists have a potential role in treating chronic prostatitis
and prostate cancer.
The rest of this article can be read in Volume 9 Issue 12 of
Prostate Forum. Click here to download this issue now. |
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