GENERIC NAME: nafarelin
BRAND NAME: Synarel
DRUG CLASS AND MECHANISM: Nafarelin is a synthetic
protein
chemically similar to the natural gonadotropin-releasing
hormone (GnRH), a
hormone that regulates the output of gonadotropins by the
pituitary gland
(a small gland located at the base of the brain). Gonadotropins
(FSH and
LH) are hormones necessary for estrogen production by the
ovaries. When
nafarelin (known scientifically as a GnRH analog) is
administered
continuously to a women in her reproductive years, the
pituitary output of
FSH and LH, along with the ovary output of estrogen are
suppressed.
Suppression of estrogen production causes menstruation to stop,
resulting
in a temporary (but reversible) state of "menopause".
This
temporary menopause is important in shrinking endometriosis
tissue and in
relieving pain of endometriosis.
Endometriosis is a condition whereby the cells which normally
form the
inside of the uterus (endometrium) are instead found outside of
the
uterus. These abnormally located cells (called endometrial
implants) are
most commonly found on the ovaries, the fallopian tubes, outer
surfaces of
the uterus or intestines, and on the surface lining of the
pelvic cavity.
Like the normal endometrium, implants respond to the hormones
of the
menstrual cycle, i.e., they build up during the month, then
break down and
bleed during menstruation. However, unlike normal endometrium,
the
implants bleed internally (blood from implants cannot exit the
body). The
internal bleeding, followed by tissue inflammation and
subsequent
scarring, is believed to be responsible for the symptoms of
pain and
infertility in women with endometriosis. Nafarelin has been
found to be
effective in relieving the pain of endometriosis and shrinking
the
endometrial implants.
Please read the Endometriosis article for further information and different treatment options
(medical and
surgical) of this condition.
PRESCRIPTION: yes
GENERIC AVAILABLE: no
PREPARATIONS: nasal spray
STORAGE: Store the bottle upright at room temperature.
Avoid
temperatures above 86 degrees F (30 degrees C), and protect
bottle from
light.
PRESCRIBED FOR: Nafarelin is prescribed for the
management of
endometriosis, including pain relief and shrinking of the
endometrial
implants.
DOSING: Unless the doctor has given special
instructions,
nafarelin is given twice daily (about every 12 hours) for a
total of 6
months. The first dose of nafarelin is to be taken between the
second and
fourth day after menstrual bleeding begins. After the first two
months of
nafarelin treatment, most women can expect a decrease in
menstrual flow,
and periods may stop altogether. Women who continue to
experience normal
menstrual cycles after two months of treatment should be
re-evaluated by
their doctors.
For optimal effectiveness and safety, nafarelin has to be given
continuously without interruption. Missing one or more doses
can cause
vaginal bleeding. Missing successive doses can cause release of
an egg
from the ovary (ovulation) and result in pregnancy, unless
proper
contraceptive measures have been followed. Since birth control
pills
cannot be used with nafarelin, it is important to use non-hormonal methods
of contraception ( such as diaphragm with contraceptive jelly,
IUD, or
condoms) while taking nafarelin.
Absorption of nafarelin is not affected by a cold or runny
nose. If
decongestants nasal spray are needed, they should be taken 30
minutes or
more after using nafarelin.
DRUG INTERACTIONS: Nafarelin should
not be used by women with undiagnosed
abnormal
menstrual bleeding.
The low estrogen state and the temporary menopause induced by
nafarelin
can cause a small amount of bone thinning, which may only
partially
recover after stopping treatment. During one 6 month treatment
period, the
amount of bone thinning is usually not significant. Patients
should
discuss this possibility with their doctors, and alert their
doctors to
conditions that can increase the risk of bone thinning. These
conditions
include chronic tobacco use, excessive use of alcohol, family
history of
osteoporosis, and taking other medications that can cause bone
thinning
(such as anticonvulsants or corticosteroids).
PREGNANCY: Nafarelin should not be used in
pregnancy or
in women who may become pregnant while receiving the
medication. Safe use of nafarelin in pregnancy has not
been
established. Pregnancy must be excluded before starting
treatment with
this medication, and a non-hormonal method of contraception
should be used
during treatment.
NURSING MOTHERS: Nafarelin should
not be used by nursing mothers.
SIDE EFFECTS: Side effects of nafarelin are mostly
related to
the low estrogen state. Side effects include hot flashes,
vaginal dryness,
headaches, mood changes, and decreased interest in sex. Some
patients may
experience acne, muscle pain, reduced breast
size, and
irritation of the
tissue inside the nose. These side effects should disappear
after stopping
the medication.
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From the Doctors at MedicineNet.com  |
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Back to Medications IndexLast Editorial Review: 12/31/1997
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