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Antihistamines
Some patients report a decrease in IC
symptoms using other antihistamines or
medicines with antihistamine properties.
Though the most widely used antihistamine to
treat IC is hydroxyzine, some people with IC
find relieve from Claritin, Benadryl, and
Singulair.
Dosage & Treatment Plan
Most patients start with a 10 to 25 milligram
(mg) dosage of Atarax, Vistaril or their generic
equivalent at bedtime every night for 1 week,
and progress to 50 mg every night the second
week. Ideally, within one month the dosage is
increased to 75 mg, 50 mg taken at night and
25 mg taken during the day. Benefits of
hydroxyzine may be seen within a few weeks
to two months after initiating therapy.
To decrease the sedating side effects, some
patients start hydroxyzine therapy at a 10 mg
dosage, available with Atarax or in the liquid
form, and work their way up, gradually, to a
maximum dosage of 50 to 75 mg. After one
year some patients are able to decrease their
dosage by one-half. Others report that upon
reducing their dosage, symptoms will return
within a few days.
Potential Side Effects
Side effects include sedation, dry mouth, and
increased depression in patients diagnosed
with concurrent depression.
Hydroxyzine
A mild anti-anxiety drug, hydroxyzine is
available in two oral forms:
 Hydroxyzine pamoate (Vistaril)
 Hydroxyzine hydrochloride (Atarax)
Hydroxyzine affects mast cell degranulation,
which is thought to play a part in some IC
patients’ symptoms, especially those who
have a history of allergies, migraines and
irritable bowel syndrome. Hydroxyzine has
been shown to improve these conditions, as
well as IC. Hydroxyzine has been found to
decrease:
 Nocturia (night time voiding)
 Daytime frequency
 Pain (burning, pressure, painful
intercourse)
Hydroxyzine pamoate has a slightly higher
absorption rate. Hydroxyzine-HCL is a liquid
form available for patients allergic to fillers or
dyes used in the capsules or pills.
Interstitial Cystitis Association © 2009
www.ichelp.org
RFZ/ Updated Jul 2009
Printed Nov 2009
Take this medicine early in the evening initially
to avoid excessive morning drowsiness. Most
patients report that daytime drowsiness
disappears within four to five days after
beginning hydroxyzine therapy. Some patients
report that with each dosage increase, the
drowsiness period is shorter and not as intense.
Pregnancy & Warnings
Animal studies have found that fetal
abnormalities occur at doses ten times higher
than given to humans. It is not recommended
that hydroxyzine be used if pregnant or
nursing. Hydroxyzine is contraindicated for use
in epileptic patients.
Anti-seizure Medicines
Originally developed as an anti-seizure
medicine, gabapentin (neurontin) is also used
to treat nerve-related pain. Some types of IC
pain may to be generated by nerve endings
and the central nervous system. A few small
studies showed that gabapentin may improve
symptoms in some IC patients.
Histamine Blockers
Most antihistamines prescribed for allergy
and IC are called "H1" blockers. When
histamines bind to the histamine receptors on
cells, that produces an allergic reaction. The
H1 receptors aren’t the only ones that
histamines go to, however. They can also bind
to H2 receptors, and drugs that block these
receptors can also be helpful in calming
allergic reactions. H2 blockers include
 Cimetidine (Tagamet)
 Ranitidine (Zantac)
 Nizatidine (Axid)
 Famotidine (Pepcid)
By blocking these H2 receptors in the gut,
these medicines reduce stomach acid
secretions and, thus, stomach pain. Studies
with one of these H2 blockers, cimetidine,
showed it reduced bladder pain as well,
maybe because of the histamine-blocking
action. But why it works in IC really isn’t so
clear. In two small studies (one with 9 and
one with 14 patients), Tagamet reduced
bladder pain for 40 to 60 percent of the IC
patients.
In Japan, Suplatast tosilate, also known as
IPD-1151T and available is indicated for IC, as
well as asthma and allergies. This medicine
acts somewhat earlier in the allergic process
than histamine or leukotriene blockers do by
affecting IgE. Suplatast tosilate helps
suppress the production of IgE. It also helps
to block production of cytokines and
suppresses allergy-related eosinophils. This
medicine remains under investigation in the
US.
potential side-effects -- some serious -- so a
cautionary approach is necessary and more
research is needed.
Mycophenolate (CellCept) works in the body
by reducing the immune system's ability to
produce certain reactions that can cause
inflammation, pain, and discomfort.
Mycophenolate mofetil is approved by the
US Food and Drug Administration (FDA) for
use in patients who have had an organ
transplant. However, a large national study
sponsored by the National Institutes of Health
(NIH) did not find mycophenolate mofetil to
be effective for IC and the study was
ultimately canceled.
Leukotriene Inhibitors
Leukotrienes which are substances produced
by some immune system cells and mast cells,
promote inflammation. Drugs that block
leukotrienes are fairly new and are being
used in the treatment of asthma and allergy.
They include the prescription medicines:
 Montelukast (Singulair)
 Zafirlukast (Accolate)
 Zileuton (Zyflo)
Some studies have implicated leukotrienes in
inflammation of the bladder in IC. The
receptors have been found in the bladder
muscle in IC patients. A study of 10 IC
patients in Denmark who took Singulair for
three months showed significant reductions in
frequency and pain.
Tagamet, Zantac, Axid, and Pepcid are
available over the counter.
Immunosuppresants
Cyclosporine, an immunosuppressive drug
used in organ transplantation, is also a
treatment for several autoimmune disorders
with good results. Because IC may have an
autoimmune component, this medicine is
being studied as a possible IC treatment. So
far the results of testing in humans have been
encouraging, but the drug does have many
Interstitial Cystitis Association © 2009
www.ichelp.org
RFZ/ Updated Jul 2009
Printed Nov 2009
The ICA provides advocacy, research
funding, and education to ensure early
diagnosis and optimal care with dignity for
people affected by IC.
Your donation dollars also enable the ICA to
continue to fund new IC research projects,
as well as work closely with Congress to
ensure ongoing IC-specific research funding
at the federal level.
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