HydrOXYzine HCL Tablets


Hydroxyzine HCL tablets are an oral antihistamine for treatment of allergic dermatitis in dogs, cats and horses.

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HydrOXYzine HCL tablets are an orally administered antihistamine that reduces itching and can produce sedative/tranquilization qualities in animals.  They are commonly used as a treatment for various forms of allergic dermatitis in dogs, cats and horses. Made by Glenmark Pharmaceuticals, Inc.

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10 mg, 25 mg, 50 mg

Purchase option

per tablet, 100 ct bottle

More Details

Hydroxyzine Tablets requires a prescription from your veterinarian.

Hydroxyzine Hydrochloride USP is a drug labeled for human use but is commonly used to treat allergic dermatitis in veterinary patients. Like other H1-receptor antihistamines, hydroxyzine acts by competing with histamine for sites on H1-receptor sites on effector cells. Antihistamines do not block histamine release, but can antagonize its effects. In addition to its antihistaminic effects, hydroxyzine possesses anticholinergic, sedative, tranquilizing, antispasmodic, local anesthetic, mild bronchodilative, and antiemetic activities.

Drug Interactions

The following drug interactions have either been reported or are theoretical in humans or animals receiving hydroxyzine and may be of in veterinary patients. Unless otherwise noted, use together is not necessarily contraindicated, but weigh the potential risks and perform additional monitoring when appropriate.

  • Anticholinergic Agents: Additive anticholinergic effects may occur when hydroxyzine is used concomitantly with other anticholinergic agents.
  • CNS Depressant Drugs, Other: Additive CNS depression may be seen if combining hydroxyzine with other CNS depressant medications, such as barbiturates, tranquilizers, etc.
  • Epinephrine: Hydroxyzine may inhibit or reverse the vasopressor effects of epinephrine; use norepinephrine or metaraminol instead.


HYDROXYZINE HYDROCHLORIDE USP Tablets are available as 25 mg and 50 mg tablets and sold by the tablet or in 100 ct and 500 ct bottles.


Use as directed by your veterinarian.

Common dosing recommendations:

Dogs - 2 mg/kg orally every 12 hours

Cats - 5 – 10 mg per cat orally every 12 hours

Horses-  0.5 – 1 mg/kg IM or orally every 12 hours


Contraindications / Precautions / Warnings

Hydroxyzine is contraindicated in patients hypersensitive to it. It should be used with caution in patients with prostatic hypertrophy, bladder neck obstruction, severe cardiac failure, angle-closure glaucoma, or pyeloduodenal obstruction.

Adverse Effects

The most likely adverse effect associated with hydroxyzine is sedation. In dogs, this is usually mild and transient. Occasionally antihistamines can cause a hyperexcitability reaction. Dogs have reportedly developed fine rapid tremors, whole body tremors and, rarely, seizures while receiving this drug. Cats may develop polydipsia, depression, or behavioral changes while on this medication.

Manufacturer Product Information

HYDROXYZINE HYDROCHLORIDE- hydroxyzine hydrochloride tablet, film coated 
Glenmark Pharmaceuticals Inc., USA

Hydroxyzine hydrochloride tablets, usp

Rx only


HydrOXYzine hydrochloride has the chemical name of 2-[2-[4-(p-Chloro--phenylbenzyl)-1-piperazinyl] ethoxy] ethanol dihydrochloride.


HydrOXYzine hydrochloride occurs as a white, odorless powder which is very soluble in water.

Each tablet for oral administration contains 10 mg, 25 mg and 50 mg hydrOXYzine HCl. Inactive ingredients include colloidal silicon dioxide, crospovidone, dibasic calcium phosphate anhydrous, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium starch glycolate and Opadry Beige (Hypromellose, Titanium dioxide, Iron oxide yellow, PEG 400, Iron oxide red, and Polysorbate 80).


HydrOXYzine hydrochloride is unrelated chemically to the phenothiazines, reserpine, meprobamate, or the benzodiazepines. HydrOXYzine hydrochloride is not a cortical depressant, but its action may be due to a suppression of activity in certain key regions of the subcortical area of the central nervous system.

Primary skeletal muscle relaxation has been demonstrated experimentally. Bronchodilator activity, and antihistaminic and analgesic effects have been demonstrated experimentally and confirmed clinically. An antiemetic effect, both by the apomorphine test and the veriloid test, has been demonstrated.

Pharmacological and clinical studies indicate that hydrOXYzine in therapeutic dosage does not increase gastric secretion or acidity and in most cases has mild antisecretory activity.

HydrOXYzine is rapidly absorbed from the gastrointestinal tract and hydrOXYzine hydrochloride’s clinical effects are usually noted within 15 to 30 minutes after oral administration.


For symptomatic relief of anxiety and tension associated with psychoneurosis and as an adjunct in organic disease states in which anxiety is manifested.

Useful in the management of pruritus due to allergic conditions such as chronic urticaria and atopic and contact dermatoses, and in histamine-mediated pruritus.

As a sedative when used as premedication and following general anesthesia, hydrOXYzine may potentiate meperidine and barbiturates, so their use in pre-anesthetic adjunctive therapy should be modified on an individual basis. Atropine and other belladonna alkaloids are not affected by the drug. HydrOXYzine is not known to interfere with the action of digitalis in any way and it may be used concurrently with this agent.

The effectiveness of hydrOXYzine as an antianxiety agent for long-term use, that is more than 4 months, has not been assessed by systematic clinical studies. The physician should reassess periodically the usefulness of the drug for the individual patient.


Oral hydrOXYzine hydrochloride is contraindicated in patients with known hypersensitivity to hydrOXYzine hydrochloride products, and in patients with known hypersensitivity to cetirizine hydrochloride or levocetirizine hydrochloride.

Hydroxyzine is contraindicated in patients with a prolonged QT interval.

HydrOXYzine, when administered to the pregnant mouse, rat, and rabbit, induced fetal abnormalities in the rat and mouse at doses substantially above the human therapeutic range. Clinical data in human beings are inadequate to establish safety in early pregnancy. Until such data are available, hydrOXYzine is contraindicated in early pregnancy. HydrOXYzine is contraindicated for patients who have shown a previous hypersensitivity to it.


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.



QT Prolongation/Torsade de Pointes (TdP): Cases of QT prolongation and Torsade de Pointes have been reported during post-marketing use of hydroxyzine. The majority of reports occurred in patients with other risk factors for QT prolongation/TdP (pre-existing heart disease, electrolyte imbalances or concomitant arrhythmogenic drug use). Therefore, hydroxyzine should be used with caution in patients with risk factors for QT prolongation, congenital long QT syndrome, a family history of long QT syndrome, other conditions that predispose to QT prolongation and ventricular arrhythmia, as well as recent myocardial infarction, uncompensated heart failure, and bradyarrhythmias.

Caution is recommended during the concomitant use of drugs known to prolong the QT interval. These include Class 1A (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmics, certain antipsychotics (e.g., ziprasidone,iloperidone, clozapine, quetiapine, chlorpromazine), certain antidepressants (e.g.,citalopram, fluoxetine), certain antibiotics (e.g., azithromycin, erythromycin,clarithromycin, gatifloxacin, moxifloxacin); and others (e.g., pentamidine, methadone,ondansetron, droperidol).

Since drowsiness may occur with use of this drug, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery while taking hydrOXYzine hydrochloride. Patients should be advised against the simultaneous use of other CNS depressant drugs, and cautioned that the effect of alcohol may be increased.

Geriatric use

A determination has not been made whether controlled clinical studies of hydrOXYzine included sufficient numbers of subjects aged 65 and over to define a difference in response from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

The extent of renal excretion of hydrOXYzine has not been determined. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selections.

Sedating drugs may cause confusion and over sedation in the elderly; elderly patients generally should be started on low doses of hydrOXYzine and observed closely.

Acute Generalized Exanthematous Pustulosis (AGEP)

Hydroxyzine may rarely cause acute generalized exanthematous pustulosis (AGEP), a serious skin reaction characterized by fever and numerous small, superficial, non-follicular, sterile pustules, arising within large areas of edematous erythema. Inform patients about the signs of AGEP, and discontinue hydroxyzine at the first appearance of a skin rash, worsening of pre-existing skin reactions which hydroxyzine may be used to treat, or any other sign of hypersensitivity. If signs or symptoms suggest AGEP, use of hydroxyzine should not be resumed and alternative therapy should be considered. Avoid cetirizine or levocetirizine in patients who have experienced AGEP or other hypersensitivity reactions with hydroxyzine, due to the risk of cross-sensitivity.


Side effects reported with the administration of hydrOXYzine hydrochloride are usually mild and transitory in nature.

Anticholinergic: Dry mouth.

Central Nervous System: Drowsiness is usually transitory and may disappear in a few days of continued therapy or upon reduction of the dose. Involuntary motor activity including rare instances of tremor and convulsions have been reported, usually with doses considerably higher than those recommended. Clinically significant respiratory depression has not been reported at recommended doses.

Cardiac System: QT prolongation, Torsade de Pointes.

In postmarketing experience, the following additional undesirable effects have been reported:

Body as a Whole: Allergic reaction.

Nervous System: Headache.

Psychiatric: Hallucination.

Skin and Appendages: Oral hydrOXYzine hydrochloride is associated with Acute Generalized Exanthematous Pustulosis (AGEP) and fixed drug eruptions in postmarketing reports.

Pruritus, rash, urticaria


The most common manifestation of hydrOXYzine hydrochloride overdosage is hypersedation. Other reported signs and symptoms were convulsions, stupor, nausea and vomiting. As in the management of overdose with any drug, it should be borne in mind that multiple agents may have been taken.

If vomiting has not occurred spontaneously, it should be induced. Immediate gastric lavage is also recommended. General supportive care, including frequent monitoring of the vital signs and close observation of the patient, is indicated. Hypotension, though unlikely, may be controlled with intravenous fluids and levaterenol or metaraminol. Do not use epinephrine as hydrOXYzine hydrochloride counteracts its pressor action.

Hydroxyzine overdose may cause QT prolongation and Torsade de Pointes. ECG monitoring is recommended in cases of hydroxyzine overdose.

There is no specific antidote. It is doubtful that hemodialysis would be of any value in the treatment of overdosage with hydrOXYzine. However, if other agents such as barbiturates have been ingested concomitantly, hemodialysis may be indicated. There is no practical method to quantitate hydrOXYzine in body fluids or tissue after its ingestion or administration.


For symptomatic relief of anxiety and tension associated with psychoneurosis and as an adjunct in organic disease states in which anxiety is manifested: in adults, 50-100 mg q.i.d.; children under 6 years, 50 mg daily in divided doses; children over 6 years, 50-100 mg daily in divided doses.

For use in the management of pruritus due to allergic conditions such as chronic urticaria and atopic and contact dermatoses, and in histamine-mediated pruritus: in adults, 25 mg t.i.d. or q.i.d.; children under 6 years, 50 mg daily in divided doses; children over 6 years, 50-100 mg daily in divided doses.

As a sedative when used as a premedication and following general anesthesia: 50-100 mg in adults, and 0.6 mg/kg of body weight in children.

When treatment is initiated by the intramuscular route of administration, subsequent doses may be administered orally.

As with all potent medication, the dosage should be adjusted according to the patient’s response to therapy.


HydrOXYzine Hydrochloride Tablets, USP 10 mg, 25 mg and 50 mg are supplied as follows:

10 mg Tablets: Beige, film coated, round, biconvex tablets debossed with ‘IG’on one side and ‘275’on other.

Bottles of 100 NDC # 68462-352-01
Bottles of 500 NDC # 68462-352-05

25 mg Tablets: Beige, film coated, round, biconvex tablets debossed with ‘IG’on one side and ‘276’on other.

Bottles of 100 NDC # 68462-353-01
Bottles of 500 NDC # 68462-353-05

50 mg Tablets: Beige, film coated, round, biconvex tablets debossed with ‘IG’on one side and ‘277’on other.

Bottles of 100 NDC # 68462-354-01
Bottles of 500 NDC # 68462-354-05

Dispense in a tight container as defined in the USP.

Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature].


Manufactured by:

InvaGen Pharmaceuticals, Inc.
Hauppauge, NY 11788

Manufactured for:


Glenmark Pharmaceuticals Inc., USA
Mahwah, NJ 07430

Questions? 1 (888) 721-7115


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