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Finasteride
(Propecia)
Sexual Dysfunction
Gynecomastia
Effects on PSA
Teratogenecity in
Females
Use in
Post-Menopausal
Women
Long-Term Benefits
and Risks
Propecia and Hair
Transplantation
Patient Monitoring
Finasteride is an
oral medication,
manufactured by
Merck, which blocks
the conversion of
testosterone to
dihydrotestosterone
(DHT), the form of
the hormone that
causes male pattern
baldness. It does
this by inhibiting
the action of the
type II 5-alpha
reductase enzyme
that is present in
higher concentration
in and around, the
hair follicles of
balding men with
androgenetic
alopecia.
The medication
causes a significant
drop in both scalp
and blood levels of
DHT. Its
effectiveness is
felt to be related
to both of these
factors. In patients
taking finasteride
1-mg/day, serum DHT
levels decreased by
68.4%. Serum
testosterone levels
actually increased
by 9.1% but remained
within the normal
range.
Finasteride was
originally marketed
for use in prostate
enlargement in men
over 50 (the
prostate also has
the type II enzyme).
This medication, in
a 5-mg per day dose,
is marketed under
the name Proscar. In
the treatment of
prostate problems,
finasteride has
produced breast
tenderness and
breast enlargement.
It has also caused
impotence and
decreased sexual
interest in a small
number of men taking
the drug.
In January 1998 the
FDA approved
finasteride 1-mg/day
(Propecia) for the
treatment of male
pattern alopecia.
The phase III human
trials, using the
1-mg dose, involved
1,553 men, ages 18
to 41, with Class II
Vertex, III Vertex,
IV or V balding
patterns, i.e. men
with mild to
moderate hair loss.
After two years,
results showed that
83% of the men
taking finasteride
either kept their
hair or grew more.
Seventeen percent
continued to lose
hair on the
medication. In the
vertex (crown), 31%
showed moderate
improvement and 5%
showed great
improvement. In the
front, only 4%
showed moderate
improvement and none
showed great
improvement.
Hair counts showed a
gain of 86 hairs in
a one-inch circle at
the end of one year.
These hairs were
significantly larger
than the fine,
miniaturized hair
seen in balding, but
it is not clear if
they all assumed the
full weight and
diameter of the
patient's original
hair. As a
comparison, hair
transplantation can
add significantly
more density in a
single session, and
this number can be
increased in
subsequent sessions.
In addition,
transplanted hair
has the full weight
and diameter of the
patient's original
hair and, of course,
is permanent.
Sexual Dysfunction
Although uncommon,
there can be side
effects of
finasteride at the 1
mg/day dose. These
include decreased
libido (1.8%),
impotence (1.3%),
and decreased volume
of ejaculate (1.2%).
It is important to
note that there was
a small incidence of
these problems in
the control group as
well. Altogether,
3.8% of men taking
finasteride 1mg
experienced some
form of sexual
dysfunction verses
2.1% in men treated
with placebo (a
sugar pill).
Most reported cases
of sexual
dysfunction occurred
soon after the
medication was
begun, but there
have been reports of
sexual dysfunction
that have occurred
at later time
points. The sexual
side effects were
reversible in all
men who discontinued
therapy and in 58%
of those who chose
to continue
treatment. When the
medication was
stopped, side
effects generally
went away within
weeks, but
occasionally took
longer.
If sexual side
effects occur, they
generally begin well
before finasteride
has had a chance to
have visible effects
on hair growth.
Therefore, men who
experience side
effects can
discontinue the
Propecia at this
time without the
risk of hair loss
due to stopping the
medication. It is
important to
remember that when
finasteride (or
minoxidil) is
discontinued, you
only lose the hair
that was gained or
preserved by the
medication, not
more. In effect, you
return to the level
of balding where you
would have been if
you had never used
the drugs in the
first place.
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Gynecomastia
Adverse reactions
related to the
breast, including
breast tenderness or
enlargement
(gynecomastia),
occurred in 0.4% of
men taking
finasteride 1-mg (Propecia),
but this was no
greater than in the
control group (those
who did not take the
medication).
In patients on the
5-mg dose (Proscar),
the time of onset of
breast enlargement
ranged from two
weeks to 2½ years.
In these patients,
80% showed partial
or complete
resolution when the
drug was stopped,
and 20% experienced
no change.
The mechanism of
breast enlargement
(gynecomastia) in
patients taking
finasteride may be
due to its ability
to block the
conversion of
testosterone to DHT.
This, in turn, may
cause more
testosterone to be
converted to
estrogen, with
estrogen then
stimulating breast
tissue. There have
been a few cases of
breast cancer in
patients on the 5-mg
dose, but a
causative
relationship with
finasteride has not
been established.
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Effects on PSA
Finasteride causes
an approximate 1/3
decrease in serum
PSA (prostate
specific antigen) in
normal men (from
0.78ng/ml to 0.52 ng/ml).
It may also blunt
the rise of PSA
levels in patients
with prostate
enlargement and in
patients who have
developed prostate
cancer.
Since PSA is used as
a screening test for
the development of
prostate cancer (the
most common type of
non-skin cancer in
men), there is a
concern that the use
of Propecia may
interfere with the
detection of this
disease. It is
important that your
personal physician
is aware that you
are taking
finasteride so that
he can take into
account any effects
that finasteride may
have on your PSA. It
is possible that the
long-term use of
Propecia may
actually decrease
the incidence of
prostate disease,
but this has not yet
been confirmed in
scientific studies.
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Teratogenecity in
Females
Finasteride is
contraindicated for
use in women of
childbearing age
since birth defects
in males can occur
if significant
amounts of the drug
are absorbed into
the body during
fetal development.
It is advised that
crushed tablets not
be handled by
pregnant women out
of concern that they
may cause harm to
the male fetus.
However, to our
knowledge, there has
not been a single
reported case of
birth defects caused
by women handling
broken or crushed
finasteride tablets.
The concern of
handling crushed
tablets seems to
revolve around the
FDA policy of
assuming maximal
possible absorption
of the full
concentration of the
medication during
any contact.
There is no evidence
that exposure of
pregnant women
through semen is a
risk to the human
fetus, but for those
patients who wish to
limit any potential
contact of
finasteride to their
partners during
pregnancy, condoms
can be worn once
conception has
occurred.
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Use in
Post-Menopausal
Women
Merck recently
carried out a study
to evaluate the
efficacy of
finasteride in
post-menopausal
women. After one
year there was no
significant hair
growth and, as a
result, the study
was terminated. It
is possible that the
low DHT levels
observed in
postmenopausal women
are responsible for
the lack of
significant response
to finasteride. The
safety profile for
the use of
finasteride in
post-menopausal
women has not been
established. See
Related Article
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Long-Term Benefits
and Risks
The effects of
finasteride are
confined to areas of
the scalp that are
thinning, but where
there is still some
hair present. It
does not seem to
grow hair in areas
that are completely
bald. Therefore, the
major benefit of
finasteride seems to
be in its ability to
slow down or halt
hair loss, or regrow
hair in parts of the
scalp that are thin.
The long-term
ability of
finasteride to
maintain one's hair
is unknown. Results
generally peak
around one year and
then are stable in
the second year or
decrease very
slightly.
The benefits of
finasteride will
stop if the
medication is
discontinued. Over
the 2-6 months
following
discontinuation, the
hair loss pattern
will generally
return to the state
that it would have
been if the
medication had never
been used.
It is important to
understand that FDA
approval of a
medication does not
mean that all the
long-term risks are
known. The small,
but nevertheless
real, incidence of
adverse reactions
seen with
finasteride
underscores the fact
that its actions are
not entirely
specific. Only
long-term experience
with the medication
will be able to
determine all of its
potential effects.
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Propecia and Hair
Transplantation
Propecia (finasteride)
has shown to be a
useful adjunct to
surgical hair
restoration for a
number of reasons.
Propecia works best
in the younger
patient who may not
yet be a candidate
for hair
transplantation.
Propecia is less
effective in the
front part of the
scalp, the area
where surgical hair
restoration can
offer the greatest
cosmetic
improvement.
Propecia can regrow,
or stabilize hair
loss, in the back
part of the scalp
where hair
transplantation may
not always be
indicated. If
Propecia is shown to
be safe and
effective in the
long-term, it will
allow the hair
restoration surgeon
the ability of
creating more
density in the
cosmetically most
important areas
(such as the front
part of the scalp),
since keeping
reserves for future
hair loss in other
areas will be less
of a concern.
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Patient Monitoring
Men age 40 or over,
should consult their
regular physician or
urologist before
beginning Propecia (finasteride
1mg). If you are age
40, or over, and are
of African descent
and/or have a family
history of prostate
disease, it is
recommended that you
be evaluated yearly.
If you have no
family history of
prostate problems
and are not of
African descent,
yearly prostate
examinations should
begin at age 50.
This may include a
rectal examination,
a baseline PSA, and
other tests that
your examining
physician feels are
appropriate.
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