What life-threatening side effect can occur with excessive dosing of promethazine?

Respiratory depression is a significant life-threatening side effect that can occur with excessive dosing of promethazine. This medication belongs to the class of antihistamines and is often used to manage nausea and vomiting. One of the central nervous system effects of promethazine is its sedative property, which can lead to respiratory depression, especially in high doses or in vulnerable populations such as the elderly, children, or individuals with existing respiratory issues. This serious side effect can manifest as a decrease in respiratory rate, shallow breathing, or complete cessation of breathing, thus posing a significant risk of hypoxia and subsequent complications, including death.

Awareness of this risk is essential for healthcare providers when administering promethazine, particularly in settings where monitoring of respiratory function can be challenging. Adjusting doses carefully and considering patient-specific factors can help mitigate such risks.