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. 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 cond...
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. 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/m...
www.fda.gov/medwatchAVENACY
Rx only
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:
 | |
| C17H21NO • HCl | MW 291.82 |
Diphenhydramine hydrochloride occurs as a white crystalline powder and is freely soluble in water and alcohol.
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.
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.
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.
For active treatment of motion sickness.
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.
This drug should not be used in neonates or premature infants.
Because of the higher risk of antihistamines for infants generally, and for neonates and prematures in particular, antihistamine therapy is contraindicated in nursing mothers.
Because of the risk of local necrosis, this drug should not be used as a local anesthetic.
Hypersensitivity to diphenhydramine hydrochloride and other antihistamines of similar chemical structure.
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.
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.
Antihistamines are more likely to cause dizziness, sedation and hypotension in elderly patients.
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.
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.
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.
Long-term studies in animals to determine mutagenic and carcinogenic potential have not been performed.
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.
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.
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.
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.
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.
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.
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.
Diphenhydramine Hydrochloride Injection, USP 50 mg per mL is a clear, colorless solution supplied as follows:
| NDC | Diphenhydramine Hydrochloride Injection, USP | Package Factor |
| 83634-781-01 | 50 mg per mL Single-Dose Vial | 25 vials per carton |
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 – 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
| Class | Version | Type | Effective |
|---|---|---|---|
| DIPHENHYDRAMINE Pharmacologic Class Indexing | 3 | Indexing - Pharmacologic Class | 20180813 |
| Product concept | Relation | Version | Effective |
|---|---|---|---|
| 0e2e0f88-b076-afe1-4bdd-32bca4375bec | Product name | 3 | 20250127 |
| 3e48c9c4-918d-5d23-2f0b-d2398b06be54 | Product name | 1 | 20140508 |
| 865c72dd-0d94-daac-f728-ddd4ded2a79e | Product name | 1 | 20140508 |
| Package NDC | Product | Description | Form | Quantity | Strength | SPL version |
|---|---|---|---|---|---|---|
| 83634-781-01 | Diphenhydramine | 25 in 1 CARTON | INJECTION, SOLUTION | 25 | 4 | |
| 83634-781-41 | Diphenhydramine | 1 mL in 1 VIAL, SINGLE-DOSE | INJECTION, SOLUTION | 1 | 4 |
| Package NDC | Billing unit | Product NDC | DailyMed indexing SPL | SPL version | Effective |
|---|---|---|---|---|---|
| 83634-781-01 | ML - Milliliter | 83634-781 | 409e0a2a-2382-4f9b-a6c6-5d1142e53bb6 | 1 | 2026-03-17 |
| 83634-781-41 | ML - Milliliter | 83634-781 | e7e4e295-f33c-410a-a64c-ff1f870886ba | 1 | 2026-03-17 |
Every source-derived product name is available through these pages.
| Product NDC | Package NDC |
|---|---|
| 83634-781 | 83634-781-41, 83634-781-01 |
Every source-derived ingredient row is available through these pages.
| Name | UNII | Kind |
|---|---|---|
| diphenhydramine hydrochloride | TC2D6JAD40 | ACTIB |
| SODIUM HYDROXIDE | 55X04QC32I | IACT |
| HYDROCHLORIC ACID | QTT17582CB | IACT |
All distinct exact application/product contexts derived from this label’s complete NDC list are paginated below.
| Application-product | Trade name | Ingredient | Strength | Dosage form / route | TE codes | RLD / RS | Approval date |
|---|---|---|---|---|---|---|---|
| A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 |
| Application-product | TE code |
|---|---|
| A205336-001 | AP |
Observed FDA ZIP history: Each table is queried independently by exact application/product key from successfully parsed Orange Book snapshots. Capture times identify archived source observations; absence or a change between snapshots is not inferred. FDA publication files that were not recoverable as structured ZIP data are not represented as states.
| Captured | Edition | Application-product | Trade name | Strength | Dosage form / route | Product TE source text | RLD / RS | Approval date | Source SHA-256 |
|---|---|---|---|---|---|---|---|---|---|
| 2026-09-14 22:38:34 | 2026-08 | A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 | 84e616aacf4f… | |
| 2026-08-18 06:07:40 | 2026-07 | A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 | caaa826d4ba7… | |
| 2026-02-19 14:30 UTC | 2026-02 | A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 | 011fe1cb6892… | |
| 2025-12-14 10:44 UTC · 2 captures of this ZIP | 2025-12 | A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 | 31067a03dcf5… | |
| 2025-08-23 18:47 UTC | 2025-08 | A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 | 6a471c1ec25d… | |
| 2026-07-26 02:55 UTC · 3 captures of this ZIP | 2026-06 | A205336-001 | DIPHENHYDRAMINE HYDROCHLORIDE | 50MG/ML | INJECTABLE / INJECTION | AP | 2025-06-24 | a50c72e98297… |
| Captured | Edition | Application-product | TE code | Order | Source SHA-256 |
|---|---|---|---|---|---|
| 2026-09-14 22:38:34 | 2026-08 | A205336-001 | AP | 1 | 84e616aacf4f… |
| 2026-08-18 06:07:40 | 2026-07 | A205336-001 | AP | 1 | caaa826d4ba7… |
| 2026-02-19 14:30 UTC | 2026-02 | A205336-001 | AP | 1 | 011fe1cb6892… |
| 2025-12-14 10:44 UTC · 2 captures of this ZIP | 2025-12 | A205336-001 | AP | 1 | 31067a03dcf5… |
| 2025-08-23 18:47 UTC | 2025-08 | A205336-001 | AP | 1 | 6a471c1ec25d… |
| 2026-07-26 02:55 UTC · 3 captures of this ZIP | 2026-06 | A205336-001 | AP | 1 | a50c72e98297… |
OpenFDA label data provides additional search and identifier links. DailyMed’s Structured Product Label is the canonical label on FDA.report. Matching records are deduplicated before they are shown below.
| Brand | Generic | Manufacturer | SPL set ID | Effective date | Available safety fields | Join |
|---|---|---|---|---|---|---|
| Diphenhydramine | DIPHENHYDRAMINE HYDROCHLORIDE | Avenacy, LLC | 00f862aa-6917-45c7-b6aa-1bebb0a45e14 | 2025-05-16 | Warnings, Adverse reactions | 83634-781-41 83634-781-01 83634-781 83634078141 83634078101 908025cf-e126-4241-b794-47d2fd90078e 00f862aa-6917-45c7-b6aa-1bebb0a45e14 |
Adverse event summaries are temporarily unavailable. Other product information remains available.