From the Research
The daily maximum dose of Phenergan DM (promethazine with dextromethorphan) for adults is 6 teaspoons (30 mL) per day, divided into doses taken every 4 to 6 hours, which equals a maximum of 60 mg of promethazine and 180 mg of dextromethorphan per day, as supported by the most recent and highest quality studies available, such as 1. This medication works through two active ingredients: promethazine, an antihistamine that reduces allergic symptoms and provides sedative effects, and dextromethorphan, a cough suppressant that works by affecting signals in the brain that trigger the cough reflex. Some key points to consider when prescribing Phenergan DM include:
- Exceeding the recommended dose can lead to serious side effects including severe drowsiness, confusion, irregular heartbeat, or even hallucinations, as reported in studies such as 2.
- This medication should not be used in children under 2 years of age due to the risk of respiratory depression.
- The potential for abuse and misuse of promethazine, particularly in combination with other substances, is a significant concern, as highlighted in studies such as 1.
- Healthcare professionals should be vigilant and monitor patients closely for signs of abuse or misuse, particularly when prescribing Phenergan DM in combination with other medications, as reported in studies such as 3 and 4.