What is the use of Promethazine (Phenergan)?

From the Guidelines

Promethazine is a phenothiazine with antihistamine, sedative, anti-emetic, and anticholinergic effects, and its use is recommended for the management of allergic reactions, postoperative nausea and vomiting, and as an adjuvant for postoperative pain and sedation, with a typical dose of 12.5-25 mg intravenously 1.

Key Uses of Promethazine

• Management of allergic reactions and anaphylaxis
• Treatment of postoperative nausea and vomiting
• Adjuvant for postoperative pain and sedation
• Adjunct for sedation during minor surgical and endoscopic procedures

Mechanism of Action and Pharmacokinetics

• Blocks postsynaptic dopaminergic receptors in the brain and has a strong-adrenergic inhibitory effect
• Competitive histamine H-receptor antagonist
• Clinical effects evident within 5 minutes of intravenous administration, with a duration of action of 4-6 hours and a plasma half-life of 9-16 hours 1

Dosage and Administration

• Typical dose: 12.5-25 mg intravenously, infused slowly to minimize the risk of hypotension
• Total dose: 25-100 mg may be used as an adjuvant to narcotics and benzodiazepines
• Reduction in the dosage of standard sedation agents may be required when using promethazine 1

Important Considerations

• Use with caution in elderly patients, those with respiratory conditions, and children under 2 years due to risk of respiratory depression
• Potential interactions with other central nervous system depressants, such as alcohol and opioids, which can cause dangerous levels of sedation 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 reactions: treatment of perennial and seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, and mild, uncomplicated allergic skin manifestations
• Sedation: preoperative, postoperative, or obstetric sedation, and sedation in both children and adults
• Pain management: therapy adjunctive to meperidine or other analgesics for control of post-operative pain
• Nausea and vomiting: prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery, and antiemetic therapy in postoperative patients
• Motion sickness: active and prophylactic treatment 2

From the Research

Uses of Promethazine

• Promethazine is a medicinal product used to treat various conditions, including nausea and vomiting, motion sickness, and hyperemesis gravidarum 3, 4.
• It is often used in combination with other ingredients, such as dextromethorphan, paracetamol, and/or expectorants 5.
• Promethazine has been shown to be effective in reducing symptoms of nausea and vomiting in patients with gastritis or gastroenteritis 4.
• It is also used as a sedative/hypnotic agent, and its use has increased in recent years, particularly in the care of drug addicts 6.

Medical Conditions Treated with Promethazine

• Nausea and vomiting related to gastritis or gastroenteritis 4
• Motion sickness 7
• Hyperemesis gravidarum 3
• Uncomplicated nausea and vomiting in the emergency department 4

Comparison with Other Medications

• Promethazine has been compared to other antiemetic agents, such as prochlorperazine, and has been shown to be less effective in some cases 4.
• It has also been compared to metoclopramide, and has been shown to have similar efficacy in treating nausea and vomiting 3.
• Promethazine has been used in combination with other medications, such as pyridoxine-doxylamine, to treat hyperemesis gravidarum 3.