What is the use of Phenergan (Promethazine)?

From the Guidelines

Phenergan (promethazine) should be used with caution and at the lowest effective dose, typically ranging from 12.5 to 25 mg taken orally every 4-6 hours as needed, due to its potential for respiratory depression and other side effects, as noted in the most recent study 1.

Key Points

• Phenergan is a first-generation antihistamine medication used to treat allergies, motion sickness, nausea, vomiting, and as a sedative.
• The typical adult dose ranges from 12.5 to 25 mg taken orally every 4-6 hours as needed, with a maximum daily dose of 150 mg, as stated in 1.
• Phenergan works by blocking histamine H1 receptors and has anticholinergic properties that help reduce nausea and vomiting, as explained in 1.
• Common side effects include drowsiness, dry mouth, blurred vision, and constipation, as mentioned in 1.
• This medication should be used with caution in elderly patients and those with respiratory conditions, as it can cause respiratory depression, as warned in 1.
• Phenergan should not be used in children under 2 years due to the risk of respiratory depression, and it can interact with other central nervous system depressants, potentially increasing sedation, as noted in 1.

Considerations

• The use of Phenergan may require a reduction in the dosage of standard sedation agents, as stated in 1.
• The clinical effects of promethazine are evident within 5 minutes of intravenous administration, and its duration of action is 4 to 6 hours, as explained in 1.
• The plasma half-life of promethazine is 9 to 16 hours, as mentioned in 1.
• Other treatment options for nausea and vomiting, such as ondansetron, granisetron, and aprepitant, may be considered, as discussed in 1 and 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 main uses of Phenergan (promethazine) are:

• 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
• Nausea and vomiting: prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery
• Pain control: therapy adjunctive to meperidine or other analgesics for control of post-operative pain
• Motion sickness: active and prophylactic treatment
• Antiemetic therapy: in postoperative patients 2

From the Research

Phenergan Overview

• Phenergan, also known as promethazine, is a histamine H1 receptor competitive antagonist with antihistaminic, sedative, anti-kinetotic, antiemetic, and antimuscarinic effects 3.
• It has been used as a treatment option for various indications since its approval in 1951.

Therapeutic Uses

• Promethazine is utilized for the treatment of nausea and vomiting, which are common reasons for emergency department visits 3.
• It offers a suitable alternative antiemetic for use in the emergency department due to its distinct mechanism of action 3.

Safety and Toxicity

• Injectable promethazine has been associated with rare but serious limb-threatening adverse effects after extravasation or inadvertent intra-arterial injection 3.
• Patient safety organizations have called for hospitals to remove injectable promethazine from formularies, and the U.S. Food and Drug Administration has changed the product labeling to add dilution and administration recommendations for intravenous administration 3.

Comparison with Other Antiemetics

• A randomized, placebo-controlled trial compared the efficacy of ondansetron, metoclopramide, and promethazine in reducing nausea in emergency department adults 4.
• The study found no evidence that ondansetron is superior to metoclopramide and promethazine in reducing nausea in emergency department adults 4.