Get your patient on Diphenhydramine - Diphenhydramine Hydrochloride injection, Solution (Diphenhydramine Hydrochloride)
Diphenhydramine - Diphenhydramine Hydrochloride injection, Solution prescribing information
INDICATIONS AND USAGE
Diphenhydramine hydrochloride in the injectable form is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when diphenhydramine hydrochloride in 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.
DOSAGE AND ADMINISTRATION
THIS PRODUCT IS FOR INTRAVENOUS OR INTRAMUSCULAR ADMINISTRATION ONLY. Diphenhydramine hydrochloride in the injectable form is indicated when the oral form is impractical. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. 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 hr or 150 mg/m 2 /24 hr. 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.
CONTRAINDICATIONS
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.
ADVERSE REACTIONS
The most frequent adverse reactions are underscored. 1.000000000000000e+00 General: Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose, and throat. 2.000000000000000e+00 Cardiovascular System: Hypotension, headache, palpitations, tachycardia, extrasystoles. 3.000000000000000e+00 Hematologic System: Hemolytic anemia, thrombocytopenia, agranulocytosis. 4.000000000000000e+00 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. 5.000000000000000e+00 GI System: Epigastric distress , anorexia, nausea, vomiting, diarrhea, constipation. 6.000000000000000e+00 GU System: Urinary frequency, difficult urination, urinary retention, early menses. 7.000000000000000e+00 Respiratory System: Thickening of bronchial secretions , tightness of chest or throat and wheezing, nasal stuffiness.
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.
DESCRIPTION
Diphenhydramine hydrochloride USP is an antihistamine drug having the chemical name 2-(Diphenylmethoxy)-N,N-dimethylethylamine hydrochloride. It occurs as a white, crystalline powder, is freely soluble in water and alcohol and has a molecular weight of 291.82. The molecular formula is C 17 H 21 NO • HCI. The structural formula is as follows: 
Diphenhydramine hydrochloride USP in the parenteral form is a sterile, pyrogen-free solution available in a concentration of 50 mg of diphenhydramine hydrochloride USP per mL. The solutions for parenteral use have been adjusted to a pH between 4 and 6.5 with either sodium hydroxide or hydrochloric acid.
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 hydrochloride 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 is not available.
HOW SUPPLIED
Diphenhydramine Hydrochloride Injection, USP in parenteral form is supplied as:
Sterile, pyrogen-free solution containing 50 mg diphenhydramine hydrochloride USP in a 1 mL amber color glass ampule with yellow bands and white OPC mark, and available in packages of ten packed in a PVC rondo tray in a single carton.
1 mL fill in 1 mL Ampule NDC 42571-169-54
Carton of 10 x 1 mL Ampule NDC 42571-169-55
Clear, colorless solution, free from any visible particles, no visible leaks or damage to the container closure system filled in tubular USP Type I glass vials.
1 mL fill in 2 mLVial NDC 42571-337-95
Carton of 1 mL Vial NDC 42571-337-56
Carton of 25 x 1 mL Vial NDC 42571-337-87
Carton of 5 x 1 mL Vial NDC 42571-337-78
Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Protect from freezing and light. Retain in carton until time of use.
Rx only
Manufactured by:
Micro Labs Limited
Bangalore-560 099, India.
Manufactured for:
Micro Labs USA, Inc. Somerset, NJ 08873
Rev. 03/2026
