Which antiemetic agent has a black box warning for children younger than 2 years?

Promethazine is the antiemetic agent that carries a black box warning for use in children younger than 2 years. This warning is primarily due to the increased risk of respiratory depression, which can be particularly dangerous in this age group. The FDA has emphasized that promethazine should not be used in very young patients unless the benefits outweigh the risks, as their respiratory system is still developing, making them more susceptible to adverse effects.

In contrast, ondansetron, while widely used in pediatric populations, does not have a similar black box warning and is generally considered safe for use in children over the age of 2 for the prevention of nausea and vomiting. Aprepitant is primarily used in adults and is not commonly prescribed for very young children, but it does not have a black box warning for this age group. Dronabinol, which is used for nausea related to chemotherapy or for appetite stimulation, does not have a specific black box warning for children but is used cautiously due to its psychoactive effects.

Therefore, the black box warning associated with promethazine highlights the significant safety considerations when prescribing medications to young children.