Benadryl Injection Description

Benadryl (diphenhydramine hydrochloride) 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 C17H21NO • HCl. The structural formula is as follows:

Benadryl in the parenteral form is a sterile, pyrogen-free solution available in a concentration of 50 mg of diphenhydramine hydrochloride per mL. The solutions for parenteral use have been adjusted to a pH between 5.0 and 6.0 with either sodium hydroxide or hydrochloric acid. The multidose Steri-Vials® contain 0.1 mg/mL benzethonium chloride as a germicidal agent.

Benadryl Injection - 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.

Benadryl 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.

Indications and Usage for Benadryl Injection

Benadryl in the injectable form is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when Benadryl in the oral form is impractical.

Contraindications

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 Benadryl.

Precautions

Adverse Reactions/Side Effects

The most frequent adverse reactions are underscored.

1. General: Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose, and throat
2. Cardiovascular System: Hypotension, headache, palpitations, tachycardia, extrasystoles
3. Hematologic System: Hemolytic anemia, thrombocytopenia, agranulocytosis
4. 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. Gl System: Epigastric distress, anorexia, nausea, vomiting, diarrhea, constipation
6. GU System: Urinary frequency, difficult urination, urinary retention, early menses
7. Respiratory System: Thickening of bronchial secretions, tightness of chest or throat and wheezing, nasal stuffiness

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.

Benadryl Injection Dosage and Administration

THIS PRODUCT IS FOR INTRAVENOUS OR INTRAMUSCULAR ADMINISTRATION ONLY.

Benadryl 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.

How is Benadryl Injection supplied

Benadryl in parenteral form is supplied as:

Benadryl Steri-Vials®
—sterile, pyrogen-free solution containing 50 mg diphenhydramine hydrochloride in each milliliter of solution with 0.1 mg/mL benzethonium chloride as a germicidal agent. Available in 10-mL (N 0071-4402-10) Steri-Vials.

—sterile, pyrogen-free solution containing 50 mg diphenhydramine hydrochloride in each milliliter of solution. Available in packages of twenty-five 1-mL (N 0071-4259-13) Steri-Vials.

Benadryl Steri-Dose ®
—sterile, pyrogen-free solution containing 50 mg diphenhydramine hydrochloride in a 1-mL disposable syringe (Steri-Dose). Available in packages of ten syringes (N 0071-4259-45).

Benadryl Ampoule
—sterile, pyrogen-free solution containing 50 mg diphenhydramine hydrochloride in a 1-mL ampoule. Available in packages of ten (N 0071-4259-03).

Store at controlled room temperature 15°–30°C (59°–86°F). Protect from freezing and light.

Rx only

Manufactured by:
Parkedale Pharmaceuticals, Inc.
Rochester, MI 48307

LAB-0064-3.0