What is the use of Promethazine (Phenergan)?

From the Guidelines

Promethazine is primarily used as an antihistamine, sedative, anti-emetic, and anticholinergic agent, with a typical adult dose ranging from 12.5 to 25 mg intravenously, infused slowly to minimize the risk of hypotension, as an adjuvant for sedation during minor surgical and endoscopic procedures 1. The medication has been investigated for its use in managing allergic reactions, postoperative nausea and vomiting, and as an adjunct for pain and sedation.

• Its clinical effects are evident within 5 minutes of intravenous administration, with a duration of action of 4 to 6 hours and a plasma half-life of 9 to 16 hours 1.
• The usual dose of promethazine is 12.5 to 25 mg, which may be used in combination with other sedation agents, potentially requiring a reduction in their dosage 1.
• Common side effects of promethazine include drowsiness, dry mouth, blurred vision, and constipation, and it should be used with caution in elderly patients and those with respiratory conditions due to the risk of respiratory depression 1.
• Promethazine can interact with other central nervous system depressants, such as alcohol, opioids, and benzodiazepines, potentially increasing sedation, and patients should avoid driving or operating machinery while taking this medication until they know how it affects them 1.

From the FDA Drug Label

Promethazine hydrochloride tablets are useful for: Perennial and seasonal allergic rhinitis. Vasomotor rhinitis. Allergic conjunctivitis due to inhalant allergens and foods. Mild, uncomplicated allergic skin manifestations of urticaria and angioedema. Amelioration of allergic reactions to blood or plasma. Dermographism Anaphylactic reactions, as adjunctive therapy to epinephrine and other standard measures, after the acute manifestations have been controlled. Preoperative, postoperative, or obstetric sedation. Prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery. Therapy adjunctive to meperidine or other analgesics for control of post-operative pain Sedation in both children and adults, as well as relief of apprehension and production of light sleep from which the patient can be easily aroused. Active and prophylactic treatment of motion sickness. Antiemetic therapy in postoperative patients.

The use of Promethazine (Phenergan) includes:

• Allergic conditions: perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, mild allergic skin manifestations, and dermatographism
• Sedation: preoperative, postoperative, or obstetric sedation, sedation in children and adults
• Nausea and vomiting: prevention and control of nausea and vomiting associated with anesthesia and surgery, antiemetic therapy in postoperative patients
• Pain management: therapy adjunctive to meperidine or other analgesics for control of post-operative pain
• Motion sickness: active and prophylactic treatment
• Anaphylactic reactions: as adjunctive therapy to epinephrine and other standard measures, after the acute manifestations have been controlled 2

From the Research

Uses of Promethazine

• Promethazine is used to treat nausea and vomiting, as evidenced by studies 3, 4, 5
• It is also used to treat motion sickness, allergic conditions, and as a sedative 6, 4
• Promethazine has antihistamine, anti-dopaminergic, and anticholinergic properties, making it a suitable alternative antiemetic for use in emergency departments 4

Administration and Dosage

• The preferred parenteral route of administration of promethazine is deep intramuscular injection 6
• Intravenous administration of promethazine may result in thrombophlebitis, unintentional intra-arterial administration, perivascular extravasation, and tissue necrosis 6, 4
• Low-dose intravenous promethazine (6.25 mg) has been shown to be as effective as higher doses (12.5 mg) in relieving nausea and vomiting, with less sedation 3, 5

Safety and Efficacy

• Promethazine has been associated with rare but serious limb-threatening adverse effects after extravasation or inadvertent intra-arterial injection 4
• Patient safety organizations have called for hospitals to remove injectable promethazine from formularies, and the U.S. Food and Drug Administration has added dilution and administration recommendations for intravenous administration 4
• Promethazine misuse and abuse have been reported, particularly in adolescents, and have been associated with drug-related fatalities 7