Diphenhydramine Drug Information

ONLY. Diphenhydramine hydrochloride injection, USP is indicated when the oral form is impractical. DOSAGE SHOULD BE INDIVIDUALIZED ACCORDING TO THE NEEDS AND THE RESPONSE OF THE PATIENT. Pediatric Patients, Other Than Premature Infants and Neonates 5 mg/kg/24 hours or 150 mg/m 2 /24 hours. Maximum daily dosage is 300 mg.

Divide into four doses, administered intravenously at a rate generally not exceeding 25 mg/min, or deep intramuscularly. Adults 10 mg to 50 mg intravenously at a rate generally not exceeding 25 mg/min, or deep intramuscularly; 100 mg if required; maximum daily dosage is 400 mg. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

The most frequent adverse reactions are italicized. General Urticaria; drug rash; anaphylactic shock; photosensitivity; excessive perspiration; chills; dryness of mouth, nose and throat. Cardiovascular System Hypotension, headache, palpitations, tachycardia, extrasystoles.

Hematologic System Hemolytic anemia, thrombocytopenia, agranulocytosis. Nervous System Sedation, sleepiness, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesia, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, neuritis, convulsions. Gastrointestinal System Epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation.

Genitourinary System Urinary frequency, difficult urination, urinary retention, early menses. Respiratory System Thickening of bronchial secretions, tightness of chest and wheezing, nasal stuffiness. To report SUSPECTED ADVERSE REACTIONS, contact Avenacy at 1-855-283-6229 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions Diphenhydramine hydrochloride has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc.) MAO inhibitors prolong and intensify the anticholinergic (drying) effects of antihistamines.

Pregnancy Teratogenic Effects Reproduction studies have been performed in rats and rabbits at doses up to 5 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to diphenhydramine hydrochloride. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Pediatric Use Diphenhydramine should not be used in neonates and premature infants (see CONTRAINDICATIONS ). Diphenhydramine may diminish mental alertness, or in the young pediatric patient, cause excitation. Overdosage may cause hallucinations, convulsions or death (see WARNINGS and OVERDOSAGE ). See also DOSAGE AND ADMINISTRATION section.

Use in Neonates or Premature Infants This drug should not be used in neonates or premature infants. Use in Nursing Mothers Because of the higher risk of antihistamines for infants generally, and for neonates and prematures in particular, antihistamine therapy is contraindicated in nursing mothers. Use as a Local Anesthetic Because of the risk of local necrosis, this drug should not be used as a local anesthetic.

Antihistamines are also Contraindicated in the Following Conditions Hypersensitivity to diphenhydramine hydrochloride and other antihistamines of similar chemical structure.

Antihistamine overdosage reactions may vary from central nervous system depression to stimulation. Stimulation is particularly likely in pediatric patients. Atropine-like signs and symptoms, dry mouth; fixed, dilated pupils; flushing, and gastrointestinal symptoms may also occur.

Stimulants should not be used. Vasopressors may be used to treat hypotension.