PHENERGAN- promethazine hydrochloride injection, solution
Baxter Healthcare Corporation


Respiratory Depression – Pediatrics

PHENERGAN Injection should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression. Postmarketing cases of respiratory depression, including fatalities, have been reported with use of promethazine in pediatric patients less than 2 years of age. Caution should be exercised when administering PHENERGAN Injection to pediatric patients 2 years of age and older (see WARNINGS — Respiratory Depression ).

Severe Tissue Injury, Including Gangrene

PHENERGAN Injection can cause severe chemical irritation and damage to tissues regardless of the route of administration. Irritation and damage can result from perivascular extravasation, unintentional intra-arterial injection, and intraneuronal or perineuronal infiltration. Adverse reactions include burning, pain, thrombophlebitis, tissue necrosis, and gangrene. In some cases, surgical intervention, including fasciotomy, skin graft, and/or amputation have been required (see WARNINGS — Severe Tissue Injury, Including Gangrene ).

Due to the risks of intravenous injection, the preferred route of administration of PHENERGAN Injection is deep intramuscular injection. Subcutaneous injection is contraindicated. See DOSAGE AND ADMINISTRATION for important notes on administration.


PHENERGAN (promethazine hydrochloride) Injection, is a sterile, pyrogen-free solution for deep intramuscular or intravenous administration. Promethazine hydrochloride (10H -Phenothiazine-10-ethanamine,N,N, α-trimethyl-, monohydrochloride, (±)-) is a racemic compound and has the following structural formula:

promethazine hydrochloride structural formula

C17 H21 ClN2 S MW 320.88

Each mL contains promethazine hydrochloride, either 25 mg or 50 mg, edetate disodium 0.1 mg, calcium chloride 0.04 mg, sodium metabisulfite 0.25 mg and phenol 5 mg in Water for Injection. pH 4.0 to 5.5; buffered with acetic acid-sodium acetate.

PHENERGAN (promethazine hydrochloride) Injection is a clear, colorless solution. The product is light sensitive. It should be inspected before use and discarded if either color or particulate is observed.


Promethazine hydrochloride is a phenothiazine derivative which possesses antihistaminic, sedative, antimotion-sickness, antiemetic, and anticholinergic effects. Promethazine is a competitive H1 receptor antagonist, but does not block the release of histamine. Structural differences from the neuroleptic phenothiazines result in its relative lack (1/ 10 that of chlorpromazine) of dopamine antagonist properties. Clinical effects are generally apparent within 5 minutes of an intravenous injection and within 20 minutes of an intramuscular injection. Duration of action is four to six hours, although effects may persist up to 12 hours. Promethazine hydrochloride is metabolized in the liver, with the sulfoxides of promethazine and N-desmethylpromethazine being the predominant metabolites appearing in the urine. Following intravenous administration in healthy volunteers, the plasma half-life for promethazine has been reported to range from 9 to 16 hours. The mean plasma half-life for promethazine after intramuscular administration in healthy volunteers has been reported to be 9.8 ± 3.4 hours.


PHENERGAN Injection is indicated for the following conditions:

  1. Amelioration of allergic reactions to blood or plasma.
  2. In anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled.
  3. For other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.
  4. For sedation and relief of apprehension and to produce light sleep from which the patient can be easily aroused.
  5. Active treatment of motion sickness.
  6. Prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery.
  7. As an adjunct to analgesics for the control of postoperative pain.
  8. Preoperative, postoperative, and obstetric (during labor) sedation.
  9. Intravenously in special surgical situations, such as repeated bronchoscopy, ophthalmic surgery, and poor-risk patients, with reduced amounts of meperidine or other narcotic analgesic as an adjunct to anesthesia and analgesia.


Children Less Than 2 Years of Age

PHENERGAN Injection is contraindicated for use in pediatric patients less than two years of age due to the risk of respiratory depression ( see WARNINGS — Respiratory Depression).

Comatose State

PHENERGAN Injection is contraindicated in comatose states.

Intra-Arterial Injection

Under no circumstances should PHENERGAN Injection be given by intra-arterial injection due to the likelihood of severe arteriospasm and the possibility of resultant gangrene (see WARNINGS — Severe Tissue Injury, Including Gangrene).

Subcutaneous Injection

PHENERGAN Injection should not be given by the subcutaneous route because evidence of chemical irritation has been noted, and necrotic lesions have resulted following subcutaneous injection. The preferred parenteral route of administration is by deep intramuscular injection.

Idiosyncratic Reaction or Hypersensitivity

PHENERGAN Injection is contraindicated in patients who have demonstrated an idiosyncratic reaction or hypersensitivity to promethazine or other phenothiazines.


Respiratory Depression

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