NATIONAL
CALIFORNIA
VENTURA
mechanism
  • Competes with histamine for the H1-receptor
indications
  • Treatment of nausea/vomiting
contraindications
  • Treatment of lower respiratory tract symptoms
  • Children < 2 years of age
dosing

Adult

Oral, Rectal, IM, IV: 25 mg

Pediatric

Oral, Rectal, IM, IV: 0.5 mg/kg

administration
Oral and rectal routes are preferred. IV and IM administration is generally avoided due to risk of severe tissue injury.
onset

Oral, IM: 20 minutes

IV: 5 minutes

duration

4 to 6 hours

notes
  • Pediatric patients: Promethazine should not be used in pediatric patients younger than 2 years because of the potential for fatal respiratory depression.
  • Tissue injury: Promethazine can cause severe chemical irritation and damage to tissues regardless of the route of administration.
dosage form
Oral Tablet, Rectal Suppository: 12.5 mg, 25 mg, 50 mg Injection Solution: 25 mg/mL (1 mL); 50 mg/mL (1 mL)
brand name
Phenergan
adverse reactions
  • Anticholinergic effects
    • Blurred vision
    • Confusion
    • Constipation
    • Dry eye
    • Urinary retention
    • Xerostomia (dry mouth)
  • Central Nervous System
    • Dizziness
    • Drowsiness
    • Delirium
    • Motor dysfunction
    • Sedation
  • Extrapyramidal symptoms
    • Akathisia (inability to remain still)
    • Dystonia (involuntary muscle contractions)
    • Tardive dyskinesia (repetitive, involuntary movements, such as grimacing and eye blinking)
  • Neuroleptic malignant syndrome
    • Symptoms include high fever, confusion, rigid muscles, variable blood pressure, sweating, and fast heart rate. Complications may include rhabdomyolysis, high blood potassium, kidney failure, or seizures. Recovery generally occurs after drug discontinuation and with supportive care
  • Orthostatic hypotension
    • Related to the alpha1-adrenergic receptor blockade and anticholinergic effects
  • Respiratory depression
    • Rare but fatal respiratory depression in neonates and children may occur
  • Tissue injury
    • Unintentional intraarterial administration and perivascular extravasation have been associated with local tissue necrosis
structure
promethazine.svg molecular structure