In September 2009, the Federal Drug Administration (FDA) notified healthcare professionals that a Boxed Warning has been added to the prescribing information for Promethazine hydrochloride (Phenergan) products.
Promethazine was once sold under the brand name Phenergan but is now available as a generic. This drug is a commonly prescribed anti-emetic agent used for motion sickness and nausea and vomiting. Promethazine hydrochloride is also frequently used as an adjunct to analgesics for routine preoperative or postoperative sedation.
The Boxed Warning is designed to remind practitioners of the risk of intravenous injection of this drug, which can cause severe tissue injury, including gangrene requiring amputation. There is also a risk that the drug can leach out from the vein during intravenous administration and cause serious damage to the surrounding tissue. Perivascular extravasation, or unintentional intra-arterial injection of the drug may result in irritation and tissue damage. The preferred route of administration is deep intramuscular injection. Subcutaneous injections are also contraindicated.
Healthcare providers need to monitor patients for phlebitis, blistering, swelling, and for burning or pain at the injection site.
A requested revision in the Dosage and Administration section of the label states that if health care professionals choose to administer promethazine intravenously, they should limit the drug’s concentration and rate of administration and ensure a properly functioning intravenous line.
Additional considerations for Healthcare Professionals:
•Promethazine hydrochloride injection, USP is available in two strengths, 50 mg/mL and 25 mg/mL. The 50 mg/mL promethazine hydrochloride injection is for deep intramuscular injection only. The 25 mg/mL promethazine hydrochloride injection may be administered by deep intramuscular injection or intravenous injection, with caution.
•If intravenous administration of promethazine is required, the maximum recommended concentration is 25 mg per mL and the maximum recommended rate of administration is 25 mg per minute through the tubing of an intravenous infusion set known to be functioning properly.
•Be alert for signs and symptoms of potential tissue injury including burning or pain at the site of injection, phlebitis, swelling, and blistering. These symptoms may only appear hours after administration.
•Injections should be stopped immediately if a patient complains of pain during injection.
•Promethazine should not be used in patients less than 2 years of age due to the risk of fatal respiratory depression.