The FDA said promethazine hydrochloride, a generic drug used to manage allergies and motion sickness, should be administered by intramuscular injection. Intravenous injection can cause chemical irritation and tissue damage, an FDA alert states.

By FRANK VINLUAN

An old drug with a wide range of uses now has a new FDA alert that could spare patients from some severe reactions.

The FDA communication covers promethazine hydrochloride, a medicine approved for managing allergic reactions, motion sickness, and post-operative nausea and vomiting. It’s also used as a sedative or as an adjunct to analgesics.

While promethazine is available in oral formulations, the FDA alert issued Wednesday covers versions administered either as a deep intramuscular injection or as a slow intravenous injection. The agency now says it recommends administration by deep intramuscular injection to reduce the risk of severe chemical irritation and damage to tissues.

If promethazine must be dosed intravenously, the FDA advises that clinicians follow updated drug label information stating the drug should be diluted and infused through an intravenous catheter inserted in a large vein, preferably through a central venous catheter. The communication specifically states the drug should not be administered using catheters placed in to veins in the hand or wrist.

Promethazine’s history dates to the 1940s when it was developed by scientists at Rhone-Poulenc Laboratories, a French chemical company whose pharmaceutical operations are now part of Sanofi. It works by blocking histamine, a substance the body produces in an allergic reaction. The drug’s activity blocking another chemical called acetylcholine led to its use in other indications, such as managing nausea and motion sickness. The generic drug is available in the U.S. as Promethegan and Phenergan, among other names.

The FDA alert states that promethazine manufacturers must update their prescribing information to include the new safety details. The carton labeling and container labels must also be updated with the corresponding information.

Photo by FDA