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What is
Zileuton? |
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Zileuton is an active oral inhibitor of the
enzyme 5-lipoxygenase, which forms leukotrienes
from arachidonic acid. The chemical name of
zileuton is 1-(1-Benzo[b]thien-2-ylethyl)-l-hydroxyurea.
The
molecular formula of zileuton is C11H12N2O2S
with a molecular weight of 236.29. The
formulation from the manufacturer is a Racemic
mixture of R(+) and S(-)
enantiomers. |
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How does
Zileuton work? |
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Following oral administration zileuton is
rapidly absorbed with a mean time to peak serum
concentration of 1.7 hours and an average
half-life elimination of 2.5 hours. Plasma
concentrations are proportional to dose, whereas
the absolute bioavailability is unknown.
The
apparent volume of distribution of zileuton is
approximately 1.2 L/kg. Zileuton is 93% bound to
plasma proteins, primarily to albumin, with
minor binding to alpha-1-acid glycoprotein.
Elimination of zileuton is primarily through
metabolites in the urine (~95%) with the feces
accounting for the next largest amount (~2%).
The drug is metabolized by the cytochrome P450
enzymes: CYP1A2, 2C9, and 3A4. |
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Who should not use Zileuton? |
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You should not
use zileuton CR if you have liver disease, high
liver enzymes, or if you are allergic to any of
the components used to make the medicine. |
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How should I use Zileuton? |
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Swallow the extended-release
tablets whole. Do not split, chew, or crush
them.
Do not use zileuton to treat a
sudden asthma attack. Your doctor will prescribe
a short-acting inhaler to use during attacks.
Talk to your doctor about how to treat symptoms
of a sudden asthma attack.
Continue to take all other
medications that your doctor has prescribed to
treat your asthma. Do not stop taking any of
your medications or change the doses of any of
your medications unless your doctor tells you
that you should.
Tell your doctor if your asthma
worsens during your treatment. Call your doctor
if you need to use more of your fast-acting
medication than usual or if you need to use the
maximum number of doses of your fast-acting
medication.
Zileuton helps control asthma
symptoms but does not cure asthma. Continue to
take zileuton even if you feel well. Do not stop
taking zileuton without talking to your doctor. |
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What happens if I miss a Zileuton
dose?
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Take
the missed dose as soon as you remember it.
However, if it is almost time for your next
dose, skip the missed dose and continue your
regular dosing schedule. Do not take a double
dose to make up for a missed one. |
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What happens if I overdose?
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In
case of overdose, call your local poison control
center at 1-800-222-1222. If the victim has
collapsed or is not breathing, call local
emergency services at 911.
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What should I avoid while using Zileuton? |
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Before taking zileuton,
-tell your doctor and
pharmacist if you are allergic to zileuton
or any other medications.
-tell your doctor and
pharmacist what prescription and
nonprescription medications, vitamins,
nutritional supplements, and herbal products
you are taking or plan to take. Be sure to
mention any of the following: anticoagulants
('blood thinners') such as warfarin (Coumadin);
antifungals such as itraconazole (Sporanox)
and ketoconazole (Nizoral); beta blockers
such as atenolol (Tenormin), labetalol (Trandate),
metoprolol (Lopressor, Toprol XL), nadolol (Corgard),
and propranolol (Inderal); clarithromycin
(Biaxin); HIV protease inhibitors such as
atazanavir (Reyataz), indinavir (Crixivan),
nelfinavir (Viracept), ritonavir (Norvir, in
Kaletra), and saquinavir (Invirase);
nefazodone; telithromycin (Ketek); and
theophylline (Theo-24, Uniphyl). Your doctor
may need to change the doses of your
medications or monitor you carefully for
side effects.
-tell your doctor if you have
liver disease. Your doctor will probably
tell you not to take zileuton.
-tell your doctor if you have
difficulty swallowing pills, if you drink or
have ever drunk large amounts of alcohol,
and if you had liver disease in the past but
recovered.
-tell your doctor if you are
pregnant, plan to become pregnant, or are
breast-feeding. If you become pregnant while
taking zileuton, call your doctor.
The
avoidance of alcohol is recommended due to
increase risk of CNS depression as well as an
increase risk in liver toxicity. In addition,
the herbal supplement St. John's wort may
decrease the serum levels of zileuton |
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What are the possible side effects of Zileuton? |
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Zileuton may cause side effects. Tell your
doctor if any of these symptoms are severe or do
not go away.
-headache
-heartburn
-diarrhea
-muscle pain
-nose and throat irritation
-pain or fullness in the face
Some
side effects can be serious. If you experience
any of the following symptoms, call your doctor
immediately.
-rash
-hives
-pain in the upper right part
of the stomach
-nausea
-vomiting
-excessive tiredness
-itching
-yellowing of the skin or eyes
-dark urine
-flu-like symptoms |
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What other drugs will affect Zileuton? |
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Zileuton is a minor substrate of CYP1A2, 2C8/9,
3A4, and a weak inhibitor of CYP 1A2. The drug
has been shown to increase the serum
concentration or effects of theophylline,
propranolol, and warfarin. It is advised that
the doses of each medication be monitored and/or
reduced accordingly. |
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Where can I get more information? |
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If
you have questions about the medicine you are
taking or would like more information, check
with your doctor, pharmacist, or other health
care provider. |
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Zileuton
Storage |
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Keep this medication in the
container it came in, tightly closed, and out of
reach of children. Store it at room temperature
and away from excess heat and moisture (not in
the bathroom). Throw away any medication that is
outdated or no longer needed. Talk to your
pharmacist about the proper disposal of your
medication. |
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Nursing Mothers use of Zileuton |
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No reports
describing the use of zileuton during human
lactation have been located. The drug and/or its
metabolites are excreted into rat milk (1). The
molecular weight (about 236) is low enough that
passage into human breast milk should be
expected. The effects on a nursing infant from
this exposure are unknown.
Women who are
given zileuton should not breast-feed |
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Pregnancy
and use of Zileuton |
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It is not known
if zileuton crosses the human placenta to the
fetus, but the molecular weight (about 236) is
low enough that transfer should be expected.
You should only
have this medicine during pregnancy if your
doctor thinks that you need it |
