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  5. Label Information: Diphenhydramine

FDA Label for Diphenhydramine

View Indications, Usage & Precautions

Table of Contents

    1. OTHER
    2. DESCRIPTION
    3. CLINICAL PHARMACOLOGY
    4. INDICATIONS AND USAGE
    5. ANTIHISTAMINIC
    6. MOTION SICKNESS
    7. ANTIPARKINSONISM
    8. USE IN NEONATES OR PREMATURE INFANTS
    9. USE IN NURSING MOTHERS
    10. USE AS A LOCAL ANESTHETIC
    11. ANTIHISTAMINES ARE ALSO CONTRAINDICATED IN THE FOLLOWING CONDITIONS
    12. WARNINGS
    13. USE IN PEDIATRIC PATIENTS
    14. USE IN THE ELDERLY (APPROXIMATELY 60 YEARS OR OLDER)
    15. GENERAL
    16. INFORMATION FOR PATIENTS
    17. DRUG INTERACTIONS
    18. CARCINOGENESIS, MUTAGENESIS, IMPAIRMENT OF FERTILITY
    19. TERATOGENIC EFFECTS
    20. PEDIATRIC USE
    21. ADVERSE REACTIONS
    22. OVERDOSAGE
    23. DOSAGE AND ADMINISTRATION
    24. PEDIATRIC PATIENTS, OTHER THAN PREMATURE INFANTS AND NEONATES
    25. ADULTS
    26. HOW SUPPLIED
    27. STORAGE CONDITIONS
    28. PACKAGE LABEL.PRINCIPAL DISPLAY PANEL

Diphenhydramine Product Label

The following document was submitted to the FDA by the labeler of this product Avenacy, Llc. The document includes published materials associated whith this product with the essential scientific information about this product as well as other prescribing information. Product labels may durg indications and usage, generic names, contraindications, active ingredients, strength dosage, routes of administration, appearance, warnings, inactive ingredients, etc.

Other



AVENACY
Rx only


Description



Diphenhydramine Hydrochloride Injection, USP is a sterile, nonpyrogenic solution for intravenous or deep intramuscular use as an antihistaminic agent. Each mL contains diphenhydramine hydrochloride 50 mg in Water for Injection. pH 4.0 to 6.5; sodium hydroxide and/or hydrochloric acid added, if needed, for pH adjustment.

The chemical name of diphenhydramine hydrochloride is 2-(Diphenylmethoxy)-N,N-dimethylethylamine hydrochloride. The structural formula is as follows:

Structural Formula - dip0n 0003 01

Structural Formula - dip0n 0003 01

C17H21NO • HCl MW 291.82

Diphenhydramine hydrochloride occurs as a white crystalline powder and is freely soluble in water and alcohol.


Clinical Pharmacology



Diphenhydramine hydrochloride is an antihistamine with anticholinergic (drying) and sedative side effects. Antihistamines appear to compete with histamine for cell receptor sites on effector cells.

Diphenhydramine hydrochloride in the injectable form has a rapid onset of action.

Diphenhydramine is widely distributed throughout the body, including the CNS. A portion of the drug is excreted unchanged in the urine, while the rest is metabolized via the liver. Detailed information on the pharmacokinetics of diphenhydramine hydrochloride injection, USP is not available.


Indications And Usage



Diphenhydramine hydrochloride injection, USP is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when the oral form is impractical.


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.


Warnings



Antihistamines should be used with considerable caution in patients with narrow-angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy or bladder-neck obstruction.

Local necrosis has been associated with the use of subcutaneous or intradermal use of intravenous diphenhydramine.


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.


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.


Adverse Reactions



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.


Overdosage



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.


Dosage And Administration



THIS PRODUCT IS FOR INTRAVENOUS OR INTRAMUSCULAR ADMINISTRATION 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/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 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.


How Supplied



Diphenhydramine Hydrochloride Injection, USP 50 mg per mL is a clear, colorless solution supplied as follows:

NDCDiphenhydramine Hydrochloride Injection, USPPackage Factor
83634-781-01 50 mg per mL Single-Dose Vial 25 vials per carton

Storage Conditions



Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° and 30°C (59° and 86°F). [See USP Controlled Room Temperature.]

Protect from light. Keep covered in carton until time of use.

Discard unused portion.

Sterile, Nonpyrogenic, Preservative-free.
The container closure is not made with natural rubber latex.

AVENACY
Mfd. for Avenacy
Schaumburg, IL 60173 (USA)
Made in India
©2025 Avenacy

Revised: May 2025


Package Label.Principal Display Panel



PACKAGE LABEL - PRINCIPAL DISPLAY PANEL – Vial Label

NDC 83634-781-41

DiphenhydrAMINE Hydrochloride Injection, USP

50 mg per mL

For Intramuscular or Intravenous Use

HIGH POTENCY

1 mL Single-Dose Vial

Rx only

PACKAGE LABEL - PRINCIPAL DISPLAY PANEL – Vial Label - dip0n 0003 02

PACKAGE LABEL - PRINCIPAL DISPLAY PANEL – Vial Label - dip0n 0003 02


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