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GENERIC
NAME: methotrexate
BRAND
NAMES: Rheumatrex, Trexall
DRUG CLASS AND MECHANISM:
Methotrexate is classified as an antimetabolite
drug, which means it is capable of blocking the
metabolism of cells. As a result of this effect,
it has been found helpful in treating certain
diseases associated with abnormally rapid cell
growth, such as cancer of the breast and
psoriasis. Recently, methotrexate has been shown
to be effective in inducing miscarriage, for
example in patients with ectopic pregnancy. This
effect of methotrexate is attributed to its
action of killing the rapidly growing cells of
the placenta. It has also been found very
helpful in treating rheumatoid arthritis,
although its mechanism of action in this illness
is not known. It seems to work, in part by
altering aspects of immune function which may
play a role in causing rheumatoid arthritis.
PRESCRIPTION: yes
GENERIC AVAILABLE: yes
PREPARATIONS: Injectable:
25mg/ml; Tablet: 2.5mg (Rheumatrex), and 5, 7.5,
10 and 15 mg (Trexall).
STORAGE: Store between 59
and 77degrees F in a sealed container, avoid
light.
PRESCRIBED FOR:
Methotrexate is used for cancer treatment
generally in higher doses than for other uses,
and is often administered intravenously or
intramuscularly. Methotrexate is used to treat
psoriasis, an inflammatory skin disease, as well
as the arthritis that occurs in 10 percent of
these patients (psoriatic arthritis). It is also
used to treat active rheumatoid arthritis in
adults and children. It is also used to treat
other rheumatic diseases, including polymyositis
and systemic lupus erythematosus. Methotrexate
has been used to induce miscarriage in patients
with ectopic pregnancy.
DOSING: May be taken with
or without food. For rheumatoid arthritis and
psoriasis, the dose of methotrexate is given
WEEKLY, whether by injection or orally. For
psoriasis, the weekly dose is often divided into
three doses given at 12 hour intervals each
week. This has been shown to be more effective,
as it relates to the natural growth cycling of
the skin.
DRUG INTERACTIONS: Because
methotrexate can cause serious liver disease,
patients with alcoholism or liver disease should
not receive it. Patients should curtail alcohol
consumption while taking methotrexate.
Methotrexate can suppress the body's immunity.
Therefore, any symptoms of infection should be
reported to the doctor. Patients with underlying
immune deficiency diseases should not receive
methotrexate. A dry, non-productive cough can be
a result of a rare lung toxicity. Methotrexate
can impair fertility, decrease sperm count and
cause menstrual dysfunction. Safety and
effectiveness has not been established in
children.
PREGNANCY: Methotrexate
should not be used in pregnancy, as it can be
toxic to the embryo and can cause fetal defects
and spontaneous abortion (miscarriage). It
should be discontinued prior to conception if
used in either partner. Male patients should
stop taking methotrexate at least 3 months prior
to a planned conception and females should
discontinue use for at least one ovulatory cycle
before conception.
SIDE EFFECTS: Methotrexate
can be well tolerated, but also can cause severe
toxicity which is usually related to the dose
taken. The most frequent reactions include mouth
sores, stomach upset, and low white blood
counts. Methotrexate can cause severe toxicity
of the liver and bone marrow, which require
regular monitoring with blood testing. It can
cause headache and drowsiness, which may resolve
if the dose is lowered. Methotrexate can cause
itching, skin rash, dizziness, and hair loss. A
dry, non-productive cough can be a result of a
rare lung toxicity.
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