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Diphenhydramine

    Brands

    DEA Class; OTC, Rx

    Common Brand Names; Benadryl, Benadryl Allergy Dye-Free LiquiGels, Children’s Benadryl Allergy, Children’s Triaminic Thin Strips Allergy, Alka-Seltzer Plus Allergy, Nytol, PediaCare Children’s Allergy, Simply Sleep, Sominex, QlearQuil Nighttime Allergy Relief, Tranquil Nighttime Sleep Aid, Unisom SleepGels, Unisom SleepMelts, ZzzQuil, Banophen Anti-Itch, Benadryl Itch Stopping, Benadryl Extra Strength Itch Stopping, Dermamycin, Diphenhydramine-D

    • Antiemetic Agents; 
    • Antihistamines, 1st Generation

    Oral, topical, and parenteral first-generation, sedating antihistamine
    Used to treat minor allergic reactions and seasonal allergies; also used as a sleep aid and premedication for some histamine-inducing regimens
    Potential for abuse and overdose; higher than recommended systemic doses can cause serious heart problems, seizures, coma, or death

    Indicated for the prevention and treatment of allergic or hypersensitivity reactions, including anaphylaxis, angioedema, urticaria, or pruritus; also for treating symptoms (e.g., rhinorrhea, sneezing) associated with allergic rhinitis or the common cold, and for cough caused by minor throat and bronchial irritation.

    For the prevention and treatment of motion sickness or vertigo.
    For the treatment of insomnia.

    Indicated for temporary relief of pain and itching associated with insect bites, minor skin irritations, and rashes due to poison ivy, poison oak, or poison sumac

    Documented hypersensitivity

    Lower respiratory tract disease, such as acute asthma (controversial)

    Premature infants or neonates

    Nursing mothers

    Use as local anesthetic

    To make child <6 years sleep, when used for self-medication

    • Sedation
    • Confusion
    • Anticholinergic effects
    • May decrease cognitive function in geriatric patients
    • Xerostomia
    • Dry nasal mucosa
    • Pharyngeal dryness
    • Thick bronchial sputum
    • Agranulocytosis
    • Hemolytic anemia
    • Thrombocytopenia
    • Convulsions
    • Tachycardia
    • Hypotension
    • Nervousness
    • Restlessness
    • Blurred vision
    • Palpitations
    • Constipation
    • Vertigo
    • Menstrual irregularities
    • Euphoria
    • Anorexia
    • Urinary retention
    • Neuritis
    • Diplopia
    • Tinnitus

    May cause CNS depression, which can impair driving or operating heavy machinery

    May potentiate effects of sedatives such as alcohol

    Use caution in patients with angle-closure glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, thyroid dysfunction

    Elderly patients: Considered high-risk medication for this age group because it may increase risk of falls and has high incidence of anticholinergic effects; may exacerbate existing lower urinary tract conditions or benign prostatic hyperplasia; use in special situations may be appropriate; not recommended for treatment of insomnia, because tolerance develops and risk of anticholinergic effects increases

    Pregnancy category: B

    Lactation: Drug enters breast milk; contraindicated

    Maximum doses are indication-specific; do not exceed product labeling. The following are general guidelines:

    Adults

    300 mg/day PO; 400 mg/day IV or IM.

    Geriatric

    300 mg/day PO; 400 mg/day IV or IM.

    Adolescents

    300 mg/day PO; 400 mg/day IV or IM.

    Children

    5 mg/kg/24 hours PO,IV, or IM, not to exceed 300 mg/day; OTC use is not recommended in children < 6 years.

    Infants

    5 mg/kg/24 hours IV or IM. Safety and efficacy have not been established for PO formulations. OTC use is not recommended.

    Neonates

    Safety and efficacy have not been established.

    Diphenhydramine hydrochloride

    oral liquid

    • 12.5mg/5mL (Benadryl Allergy Childrens, PediaCare Children’s Allergy, Allergy Relief Childrens)
    • 50mg/30mL (ZzzQuil)

    elixir

    • 12.5 mg/5mL (Altaryl)

    syrup

    • 12.5 mg/5mL (Altaryl, Quenalin, Silphen Cough)

    tablet

    • 25mg (Benadryl, Nytol, Simply Sleep, Sominex, Simply Allergy, Tetra-Formula Nighttime Sleep)
    • 50mg (Aler-Dryl, Nytol Maximum Strength)

    capsule

    • 25mg (Benadryl Allergy Dye-Free Allergy, Anti-Hist Allergy, Allergy Relief, Diphenhist, Geri-Dryl)
    • 50mg (Banophen, Pharbedryl)

    tablet, chewable

    • 12.5mg (Benadryl Allergy Childrens)

    tablet, dispersible

    • 25mg (Unisom SleepMelts)

    strip

    • 12.5mg (Triaminnic Cough/Runny Nose)

    injectable solution

    • 50mg/mL

    cream

    • 2% plus zinc acetate 0.1%
    • 1% plus zinc acetate 0.1%

    gel

    • 2%

    spray

    • 2% plus zinc acetate 0.1%
    • 2% with menthol 1%

    stick

    • 2% plus zinc acetate 0.1%