Tablets: 10, 25, 50 and 100 mg. Capsules: 25, 50 mg. Syrup: 10 mg per teaspoonful (5mL). Suspension: 25 mg per teaspoonful (5mL). Injection: 25 and 50 mg/ml
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. These drugs include:
- oxycodone and acetaminophen (Percocet),
- hydrocodone/acetaminophen (Vicodin),
- hydromorphone (Dilaudid),
- propoxyphene (Darvon).
Hydroxyzine also adds to the effects of the tricyclic class of antidepressants, for example:
Hydroxyzine can also intensify the drying effects of other medications with anticholinergic properties, for example:
- dicyclomine (Bentyl),
- bethanechol (Urecholine),
- amitriptyline (Elavil, Endep), and
- chlorpromazine (Thorazine).
When using these drugs, the dose of hydroxyzine may require reduction.
PREGNANCY AND BREASTFEEDING SAFETY: 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.
STORAGE: Capsules, tablets, and liquids should be stored at room temperature 15 C to 30 C (59 F to 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).
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 itching (pruritus) is 25 mg given 3 or 4 times daily by mouth or by intramuscular injection. When used for sedation, the recommended dose is 50 to 100 mg orally or 25 to 100 mg by intramuscular injection. Anxiety and tension are managed with 50 to 100 mg in 4 divided doses or 50-100 mg intramuscular injection in 4 or 6 divided doses. Alcohol withdrawal is treated with a 50-100 mg injection and may be repeated every 4 to 6 hours as needed. The dose for nausea and vomiting is 25 to 100 mg by injection.
Hydroxyzine can be taken with or without food.
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, bind to the histamine receptors. When they bind to the receptors, however, 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 histamine-like 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.
Medically reviewed by Eni Williams, PharmD
Reference: FDA Prescribing Information
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