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Hyzine Side Effects

Generic Name: hydroxyzine

Note: This page contains information about the side effects of hydroxyzine. Some of the dosage forms included on this document may not apply to the brand name Hyzine.

For the Consumer

Applies to hydroxyzine: oral capsules, oral suspension or solution, parenteral injection

Side effects include:

Drowsiness, dry mouth.

For Healthcare Professionals

Applies to hydroxyzine: compounding powder, intramuscular solution, oral capsule, oral suspension, oral syrup, oral tablet

Nervous system

Nervous system side effects have included moderate to slight drowsiness. This effect is usually transitory and may disappear with continued therapy or upon discontinuation of the agent. Headache, fatigue, depression, insomnia, sedation, and nervousness have also been reported with hydroxyzine (the active ingredient contained in Hyzine) With higher than recommended doses of hydroxyzine, involuntary motor activity such as tremor and convulsions have been reported in rare instances.[Ref]


Gastrointestinal side effects have included dry mouth (most common side effect), nausea, diarrhea, abdominal pain, and increases in weight and appetite.[Ref]


Respiratory side effects have included the thickening of bronchial secretions. Rare occurrences of pharyngitis, bronchospasm, and epistaxis have also been reported.[Ref]


Cardiovascular side effects have included palpitations, hypotension, and edema.[Ref]


Dermatologic side effects have included angioedema, photosensitivity, and rash.[Ref]


Genitourinary side effects have included rare cases of urinary retention and prolonged penile erections.[Ref]


Ocular side effects have included blurred vision.[Ref]


1. Maddox DE, Reed CE "Clinical pharmacodynamics of antihistamines." Ann Allergy 59 (1987): 43-8

2. Simons FE, Simons KJ, Frith EM "The pharmacokinetics and antihistaminic of the H1 receptor antagonist hydroxyzine." J Allergy Clin Immunol 73 (1984): 69-75

3. Simons FE, Watson WT, Chen XY, Minuk GY, Simons KJ "The pharmacokinetics and pharmacodynamics of hydroxyzine in patients with primary biliary cirrhosis." J Clin Pharmacol 29 (1989): 809-15

4. "Product Information. Vistaril (hydroxyzine)." Pfizer US Pharmaceuticals, New York, NY.

5. Michel M, Dompmartin A, Louvet S, Szczurko C, Castel B, Leroy D "Skin reactions to hydroxyzine." Contact Dermatitis 36 (1997): 147-9

6. Thavundayil JX, Hambalek R, Kin NMKNY, Krishnan B, Lal S "Prolonged penile erections induced by hydroxyzine: possible mechanism of action." Neuropsychobiology 30 (1994): 4-6

Not all side effects for Hyzine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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