Label: DIPHENHYDRAMINE HYDROCHLORIDE injection

Antihistaminic

For amelioration of allergic reactions to blood or plasma, in anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled and for other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.

Motion Sickness

For active treatment of motion sickness.

Antiparkinsonism

For use in parkinsonism, when oral therapy is impossible or contraindicated, as follows: parkinsonism in the elderly who are unable to tolerate more potent agents, mild cases of parkinsonism in other age groups and in other cases of parkinsonism in combination with centrally acting anticholinergic agents.

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.

Use in Pediatric Patients

In pediatric patients, especially, antihistamines in overdosage may cause hallucinations, convulsions or death.

As in adults, antihistamines may diminish mental alertness in pediatric patients. In the young pediatric patient, particularly, they may produce excitation.

Use in the Elderly (approximately 60 years or older)

Antihistamines are more likely to cause dizziness, sedation and hypotension in elderly patients.

General

Diphenhydramine hydrochloride has an atropine-like action and, therefore, should be used with caution in patients with a history of bronchial asthma, increased intraocular pressure, hyperthyroidism, cardiovascular disease or hypertension. Use with caution in patients with lower respiratory disease, including asthma.

Information for Patients

Patients taking diphenhydramine hydrochloride should be advised that this drug may cause drowsiness and has an additive effect with alcohol.

Patients should be warned about engaging in activities requiring mental alertness, such as driving a car or operating appliances, machinery, etc.

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.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term studies in animals to determine mutagenic and carcinogenic potential have not been performed.

Pregnancy

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.

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.

Pediatric Patients, Other Than Premature Infants and Neonates

5 mg/kg/24 hours or 150 mg/m2/24 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 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.