Yes

Antihistamine

Dental: Symptomatic relief of allergic symptoms caused by histamine release which include nasal allergies and allergic dermatosis; also to produce local anesthesia through infiltration of mucous membranes

Medical: Symptomatic relief of allergic symptoms caused by histamine release which include nasal allergies and allergic dermatosis; can be used for mild nighttime sedation; prevention of motion sickness and as an antitussive; has antinauseant and topical anesthetic properties; treatment of antipsychotic-induced extrapyramidal reactions

B

Hypersensitivity to diphenhydramine or any component; should not be used in acute attacks of asthma; use in neonates is contraindicated

Causes sedation, caution must be used in performing tasks which require alertness (ie, operating machinery or driving). Sedative effects of CNS depressants or ethanol are potentiated. Use with caution in patients with angle-closure glaucoma, pyloroduodenal obstruction (including stenotic peptic ulcer), urinary tract obstruction (including bladder neck obstruction and symptomatic prostatic hypertrophy), hyperthyroidism, increased intraocular pressure, and cardiovascular disease (including hypertension and tachycardia). Diphenhydramine has high sedative and anticholinergic properties, so it may not be considered the antihistamine of choice for prolonged use in the elderly. May cause paradoxical excitation in pediatric patients, and can result in hallucinations, coma, and death in overdose. Some preparations contain sodium bisulfite; syrup formulations may contain alcohol.

Cardiovascular: Hypotension, palpitations, tachycardia

Central nervous system: Sedation, sleepiness, dizziness, disturbed coordination, headache, fatigue, nervousness, paradoxical excitement, insomnia, euphoria, confusion

Dermatologic: Photosensitivity, rash, angioedema, urticaria

Gastrointestinal: Nausea, vomiting, diarrhea, abdominal pain, xerostomia, appetite increase, weight gain, dry mucous membranes, anorexia

Genitourinary: Urinary retention, urinary frequency, difficult urination

Hematologic: Hemolytic anemia, thrombocytopenia, agranulocytosis

Neuromuscular & skeletal: Tremor, paresthesia

Ocular: blurred vision

Respiratory: Thickening of bronchial secretions

Symptoms of overdose include CNS stimulation or depression; overdose may result in death in infants and children

There is no specific treatment for an antihistamine overdose, however, most of its clinical toxicity is due to anticholinergic effects. Anticholinesterase inhibitors (eg, physostigmine, neostigmine, pyridostigmine, or edrophonium) may be useful by reducing acetylcholinesterase. For anticholinergic overdose with severe life-threatening symptoms, physostigmine 1-2 mg (0.5 mg or 0.02 mg/kg for children) I.V., slowly may be given to reverse these effects.

CYP2D6 enzyme substrate

Therapeutic effects of cholinergic agents (tacrine, donepezil) and neuroleptics may be antagonized

Central and/or peripheral anticholinergic syndrome can occur when administered with amantadine, rimantadine, narcotic analgesics, phenothiazines and other antipsychotics (especially with high anticholinergic activity), tricyclic antidepressants, quinidine and some other antiarrhythmics, and antihistamines

Syrup should not be given to patients taking drugs that can cause disulfiram reactions (ie, metronidazole, chlorpropamide) due to high alcohol content

Protect from light; the following drugs are incompatible with diphenhydramine when mixed in the same syringe: Amobarbital, amphotericin B, cephalothin, diatrizoate, foscarnet, heparin, hydrocortisone, hydroxyzine, pentobarbital, phenobarbital, phenytoin, prochlorperazine, promazine, promethazine, tetracycline, thiopental

Competes with histamine for H₁-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract; anticholinergic and sedative effects are also seen

Maximum sedative effect: 1-3 hours

Duration of action: 4-7 hours

Absorption: Oral: 40% to 60% reaches systemic circulation due to first-pass metabolism

Metabolism: Extensive in the liver and, to smaller degrees, in the lung and kidney

Half-life: 2-8 hours; elderly: 13.5 hours

Protein binding: 78%

Time to peak serum concentration: 2-4 hours

Children:

Oral: (>10 kg): 12.5-25 mg 3-4 times/day; maximum daily dose: 300 mg

I.M., I.V.: 5 mg/kg/day or 150 mg/m²/day in divided doses every 6-8 hours, not to exceed 300 mg/day

Adults:

Oral: 25-50 mg every 6-8 hours

Nighttime sleep aid: 50 mg at bedtime

I.M., I.V.: 10-50 mg in a single dose every 2-4 hours, not to exceed 400 mg/day

Topical: For external application, not longer than 7 days

Alcohol: Additive CNS effects, avoid use

Antihistamine effects at levels >25 ng/mL

Drowsiness at levels 30-40 ng/mL

Mental impairment at levels >60 ng/mL

Therapeutic: Not established

Toxic: >0.1 mg/mL

May suppress the wheal and flare reactions to skin test antigens

No information available to require special precautions

Chronic use of antihistamines will inhibit salivary flow, particularly in elderly patients; this may contribute to periodontal disease and oral discomfort

Take as directed; do not exceed recommended dose. Avoid use of other depressants, alcohol, or sleep-inducing medications unless approved by prescriber. You may experience drowsiness or dizziness (use caution when driving or engaging in tasks requiring alertness until response to drug is known); or dry mouth, nausea, or vomiting (frequent small meals, frequent mouth care, chewing gum, or sucking hard candy may help). Report persistent sedation, confusion, or agitation; changes in urinary pattern; blurred vision; sore throat, difficulty breathing, or expectorating (thick secretions); or lack of improvement or worsening or condition. Breast-feeding precautions: Do not breast-feed.

Raise bed rails, institute safety measures, assist with ambulation

Capsule, as hydrochloride: 25 mg, 50 mg

Cream, as hydrochloride: 1%, 2%

Elixir, as hydrochloride: 12.5 mg/5 mL (5 mL, 10 mL, 20 mL, 120 mL, 480 mL, 3780 mL)

Injection, as hydrochloride: 10 mg/mL (10 mL, 30 mL); 50 mg/mL (1 mL, 10 mL)

Lotion, as hydrochloride: 1% (75 mL)

Solution, topical spray, as hydrochloride: 1% (60 mL)

Syrup, as hydrochloride: 12.5 mg/5 mL (5 mL, 120 mL, 240 mL, 480 mL, 3780 mL)

Tablet, as hydrochloride: 25 mg, 50 mg

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