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GENERIC
NAME: hydroxyzine
BRAND
NAMES: Atarax; Vistaril
DRUG CLASS AND MECHANISM:
Hydroxyzine is an antihistamine with
anticholinergic (drying) and sedative properties
that is used to treat allergic reactions.
Histamine is released by the body during several
types of allergic reactions and -- to a lesser
extent -- during some viral infections, such as
the common cold. When histamine binds to its
receptors on cells, it causes changes within the
cells that lead to sneezing, itching, and
increased mucus production. Antihistamines
compete with histamine for cell receptors;
however, when they bind to the receptors they do
not stimulate the cells. In addition, they
prevent histamine from binding and stimulating
the cells. After ingestion, the molecule of
hydroxyzine is changed slightly, and this
changed hydroxyzine that also binds to cells.
(This changed hydroxyzine-called an active
metabolite--is cetirizine (Zyrtec), which is now
an FDA- approved drug.) Though both hydroxyzine
and cetirizine act as antihistamines,
hydroxyzine causes sedation as a side effect,
and cetirizine does not. Hydroxyzine was
originally approved by the FDA in 1957.
GENERIC AVAILABLE: yes
PRESCRIPTION: yes
PREPARATIONS: Tablets:
10mg, 25mg, 50mg, 100mg. Capsules: 25mg, 50mg,
100mg. Syrup: 10mg per teaspoonful (5mL).
Suspension: 25mg per teaspoonful (5mL).
STORAGE: Capsules, tablets,
and liquids should be stored below 30°C (86°F).
Liquid should not be frozen, and should be
shaken well prior to each use.
PRESCRIBED FOR: Hydroxyzine
is used for the relief of nasal and non-nasal
symptoms of various allergic conditions such as
seasonal allergic rhinitis. Although
antihistamines are the preferred class of drugs
in allergic rhinitis, they only reduce symptoms
by 40-60%. Hydroxyzine also is used as an aid
for insomnia and to induce sedation prior to
certain uncomfortable diagnostic or therapeutic
procedures.
DOSING: Hydroxyzine has its
maximal effect about 30 to 60 minutes after it
is taken. Its effects last for 4 to 6 hours.
Therefore, it is often prescribed to be taken
every 4 to 6 hours as needed for relief of
allergy-related symptoms. When used to combat
insomnia, it is prescribed to be taken 30 to 60
minutes before bedtime as needed. Patients over
the age of 60 years are especially sensitive to
the sedating effects of hydroxyzine, and the
dose should be reduced. Hydroxyzine can be taken
with or without food.
DRUG INTERACTIONS:
Hydroxyzine adds to (exaggerates) the sedating
effects of alcohol and other drugs that can
cause sedation such as the benzodiazepine class
of anti-anxiety drugs (e.g., Valium, Ativan,
Klonopin, Xanax), the narcotic class of pain
medications and its derivatives (e.g. ,
Percocet, Vicodin, Dilaudid, Codeine, Darvon),
the tricyclic class of antidepressants (e.g.
Elavil, Tofranil, Norpramin), and certain
antihypertensive medications (e.g., Catapres,
Inderal). Hydroxyzine can also intensify the
drying effects of other medications with
anticholinergic properties (e.g., Bentyl,
Urecholine, Probanthine, Elavil, Thorazine.)
When using these drugs, the dose of hydroxyzine
may require reduction, therefore.
PREGNANCY: A limited number
of studies of hydroxyzine in pregnant women
suggests that there may be a relationship
between its use in the first trimester of
pregnancy and congenital abnormalities in the
fetus. Therefore, hydroxyzine should be avoided
during the first trimester of pregnancy.
NURSING MOTHERS: It is not
known if hydroxyzine is excreted into breast
milk. In general, antihistamines are not
recommended for use during breast-feeding
because they can cause stimulation or seizures
in newborns.
SIDE EFFECTS: Hydroxyzine
can commonly cause sedation, tiredness,
sleepiness, dizziness, disturbed coordination,
drying and thickening of oral and other
respiratory secretions, and stomach distress.
Hydroxyzine may also cause confusion,
nervousness, irritability, blurred vision,
double vision, tremor, loss or appetite, or
nausea. Hydroxyzine should be used with caution
(if at all) in persons with narrow-angle
glaucoma, prostatic hypertrophy (enlarged
prostate gland), hyperthyroidism, cardiovascular
disease, hypertension, and asthma.
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