Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
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. The body releases histamine 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 the cells
to release chemical messengers that lead to sneezing,
itching, and increased
mucus production. Antihistamines, like histamine, binds to the histamine
receptors, but when they bind to the receptors they do not stimulate the cells
to release chemical messengers. In addition, they prevent histamine from binding
and stimulating the cells. Hydroxyzine itself has no activity. After ingestion,
it is converted to its active form. The active form of hydroxyzine is a drug
called cetirizine (Zyrtec). Although, both hydroxyzine and cetirizine act as
antihistamines, hydroxyzine causes more sedation than cetirizine. The FDA
approved hydroxyzine in 1956.
GENERIC AVAILABLE: Yes
PRESCRIPTION: Yes
PREPARATIONS: Tablets: 10, 25, and 50 mg. Capsules: 25, 50, and 100 mg.
Syrup: 10 mg per teaspoonful (5mL). Suspension: 25 mg per teaspoonful (5mL).
Injection: 25 and 50 mg/ml
STORAGE: Capsules, tablets, and liquids should be stored at room temperature
15-30°C (59-86°F). Liquid should not be frozen and should be shaken well prior
to each use. Injectable hydroxyzine should be stored below 30°C (86°F).
PRESCRIBED FOR: Hydroxyzine is used for the relief of pruritus (itching)
caused by various allergic conditions. Hydroxyzine is also used for treating
anxiety and tension, and inducing sedation prior to or after anesthesia.
DOSING: Hydroxyzine has its maximal effect about 30 to 60 minutes after it is
taken. Its effects last for 4 to 6 hours. The recommended dose for treating
pruritus is 25 mg given 3 or 4 times daily. When used for sedation, the
recommended dose is 50 to 100 mg. Anxiety and tension are managed with 50 to 100
mg 4 times daily. 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 [for example, diazepam (Valium), lorazepam (Ativan), clonazepam (Klonopin), alprazolam (Xanax)], the narcotic
class of pain medications and its derivatives [for example, oxycodone and acetaminophen (Percocet), hydrocodone/acetaminophen (Vicodin),
guaifenesin (Dilaudid), Codeine, propoxyphene (Darvon)], the tricyclic class of antidepressants [for example, amitriptyline (Elavil), imipramine (Tofranil), desipramine (Norpramin)], and certain antihypertensive medications [for example, clonidine (Catapres), propranolol (Inderal)]. Hydroxyzine can also intensify the drying effects of other medications with anticholinergic properties [for example, dicyclomine (Bentyl),
bethanechol (Urecholine), Probanthine, amitriptyline (Elavil),
chlorpromazine (Thorazine)]. When using these drugs, the dose of hydroxyzine may require
reduction, therefore.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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