Home
- Allergies
- Acid Reflux
- ADHD
- Anxiety Disorders
- Arthritis
- Asthma
- Back Pain
- Bipolar Disorder
- Cancer
- Cholesterol
- Cold, Flu, & Cough
- COPD
- Depression
- Diabetes
- Eye Health
- Fibromyalgia
- Heart Disease
- Heartburn/GERD
- Hypertension
- Incontinence/OAB
- Migraines
- Osteoporosis
- Rheumatoid Arthritis
- Sexual Conditions
- Sleep Disorders
- Celebrity Secrets
- Skin Problems
- Multiple Sclerosis
- X-Rays
- Yellow Fever
- Yoga
- Women's Health
- Vitamins
- Weight Loss
- Wisdom Teeth
- Ultrasounds
- Transplant
- Skin Cancer
- Pain Management
- Palliative Care
- Pneumonia
- Obesity
- Mental Health
- Liver Cancer
- Lung Disease
- Labor and Delivery
- Knee Replacement Surgery
- Kidney Stones
- Jaundice
- Integrative Medicine
- Infections
- Interventional Pulmonology
- Headaches
- High blood preasure
- HIV/AIDS
- Fever
- Gestational Diabetes
- Gas
- Food Poisoning
- Oral Care
- Dengue Fever
- Ear Infections
- Diarrhea
- Dry Skin
- Cholera
- Children's Health
- Chickenpox
- Brain Diseases
- Lower Back pain
- Bone Tumors
- Anemia
- Avoidant Personality Disorder
- Aging
- Alcohol Interaction With Medication
- Burns
- Cataracts
- Chlamydia
Hydroxyzine is a first-generation antihistamine of the diphenylmethane and piperazine class. It was first synthesized by Union Chimique Belge in 1956 and was marketed by Pfizer in the United States later the same year, and is still in widespread use today.
Due to its antagonistic effects on several receptor systems in the brain, hydroxyzine is claimed to have strong anxiolytic and mild antiobsessive as well as antipsychotic properties. Today it is used primarily for the symptomatic relief of anxiety and tension associated with psychoneurosis and as an adjunct in organic disease states in which anxiety is manifested. Because of its antihistamine effects it can also be used for the treatment of severe cases of itching, hyperalgesia and motion sickness-induced nausea, it has also been used in some cases to relieve the effects of opioid withdrawal.
Clinical description
Hydroxyzine can be administered orally or via intramuscular injection. When given orally, hydroxyzine is rapidly absorbed from the gastro-intestinal tract. The effect of hydroxyzine is notable in 30 minutes.
Pharmacokinetically, hydroxyzine is rapidly absorbed and distributed in oral and intramuscular administration, and is metabolized in the liver; the main metabolite (45%) is formed through oxidation of the alcohol moiety to a carboxylic acid by alcohol dehydrogenase, is cetirizine and overall effects are observed within one hour of administration. It has a half-life observed on average of around 3 hours in adults, with higher concentrations found in the skin than in the plasma. Cetirizine, although less sedating, is non-dialyzable and possesses similar anti-histaminergic properties. The other metabolites identified include a N-dealkylated metabolite, and an O-dealkylated 1/16 metabolite with a plasma half-life of 59 hours. These pathways are mediated principally by CYP3A4 and CYP3A5. "In animals, hydroxyzine and its metabolites are excreted in feces via biliary elimination."
Adverse reactions
Several reactions have been noted in manufacturer guidelines — deep sleep, incoordination, sedation, calmness, and dizziness have been reported in children and adults, as well as others such as hypotension, tinnitus, and headaches. Gastro-intestinal effects have also been observed, as well as less serious effects such as dryness of the mouth and constipation caused by the mild antimuscarinic properties of hydroxyzine.
Pharmacology
Hydroxyzine's predominant mechanism of action is as a potent H1 receptor inverse agonist (Ki = 2 nM). Unlike many other first-generation antihistamines, it has very low affinity for the mACh receptors (Ki = >10,000 nM) and in accordance, has a low propensity for producing anticholinergic side effects. In addition to its antihistamine activity, hydroxyzine has also been shown to act as a 5-HT2A (Ki = ~50 nM), D2 (Ki = 378 nM), and α1-adrenergic (Ki = ~300 nM) receptor antagonist. The antiserotonergic effects of hydroxyzine likely underlie its usefulness as an anxiolytic, as other antihistamines without such properties have not been found to be effective in the treatment of anxiety.
Contraindications
The administration of hydroxyzine in large amounts by ingestion or intramuscular administration during the onset of pregnancy can cause fetal abnormalities—when administered to pregnant rats, mice and rabbits, hydroxyzine caused abnormalities with doses significantly above that of the human therapeutic range. In humans, a significant dose has not yet been established in studies, and by default, the FDA has introduced contraindication guidelines in regard to hydroxyzine. Similarly the use in those at risk from or showing previous signs of hypersensitivity is also contraindicated.
Before taking Vistaril, you should talk with your healthcare provider about any other medical conditions you may have and any other medications you are taking. For example, you may not be able to safely use Vistaril if you have glaucoma, difficulty passing urine, or Alzheimer's disease. Other warnings and precautions with Vistaril apply to people with certain allergies and women who are pregnant or breastfeeding.
Some warnings and precautions to be aware of with this product include the following:
Vistaril can cause drowsiness. Be sure to see how Vistaril affects you before driving or operating heavy machinery.
Because of its anticholinergic affects, Vistaril can worsen glaucoma, Alzheimer's disease, or an enlarged prostate. Let your healthcare provider know if you experience worsening of any of these conditions while taking Vistaril.
Nursing Mothers
It is not known whether this drug is excreted in human milk. Since many drugs are so excreted, hydroxyzine should not be given to nursing mothers.
Hydroxyzine is used to treat itching caused by allergies. It is an antihistamine and works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Hydroxyzine may also be used short-term to treat anxiety or to help you feel sleepy/relaxed before and after surgery.
How to use hydroxyzine HCl
Take this medication by mouth with or without food as directed by your doctor, usually three or four times daily. If you are using the liquid form of this medication, carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.
The dosage is based on your age, medical condition, and response to treatment. In children, the dosage may also be based on weight. Do not increase your dose or take this medication more often than directed.
Tell your doctor if your condition does not improve or if it worsens.
Drowsiness, dizziness, blurred vision, constipation, or dry mouth may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To relieve dry mouth, suck (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as restlessness, confusion, hallucinations), shaking (tremor), difficulty urinating, fast/irregular heartbeat.
Get medical help right away if you have any very serious side effects, including: seizures.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
Before taking hydroxyzine, tell your doctor or pharmacist if you are allergic to it; or to cetirizine; or to levocetirizine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as emphysema, asthma), high pressure in the eye (glaucoma), heart problems, high blood pressure, kidney problems, liver problems, seizures, stomach/intestine problems (such as ulcer, blockage), overactive thyroid (hyperthyroidism), difficulty urinating (for example, due to enlarged prostate).
This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Avoid alcoholic beverages.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Liquid products may contain sugar and/or alcohol. Caution is advised if you have diabetes, liver disease, or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.
Children may be more sensitive to the side effects of this drug. This drug can often cause excitement in young children instead of drowsiness.
Older adults may be more sensitive to the side effects of this drug, especially drowsiness, confusion, constipation, or trouble urinating. Drowsiness and confusion can increase the risk of falling.
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, other antihistamines (such as diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine).
Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
Do not use with any other antihistamines applied to the skin (such as diphenhydramine cream, ointment, spray) because increased side effects may occur.
Hydroxyzine is very similar to cetirizine and levocetirizine. Do not use these medications while using hydroxyzine.
This medication may interfere with certain laboratory tests (including allergy skin testing, urine corticosteroids level), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
If overdose is suspected, contact a poison control center or emergency room immediately.Symptoms of overdose may include: severe drowsiness, seizures. In children, mental/mood changes (such as restlessness, irritability) may occur before drowsiness.
Notes
Do not share this medication with others.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Storage
Store at room temperature away from light and moisture. Do not store in the bathroom. Do not freeze liquid forms of this medication. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised December 2013. Copyright(c) 2013 First Databank, Inc.
