From the Guidelines
The recommended adult dose of dextromethorphan (DM) for cough suppression is 10-15 mg every 4-8 hours as needed, not exceeding 120 mg in 24 hours. This dosage is based on the most recent and highest quality study available, which suggests that dextromethorphan can be effective in reducing cough symptoms in adults 1. The study provides a dosage range of 10-15 mg tid or qid, with a maximum dose of 120 mg/d. It's essential to note that the dosage may vary depending on the specific product concentration and formulation.
When using dextromethorphan, it's crucial to follow the recommended dosage and take it only as directed. Adults should avoid exceeding the maximum daily dose of 120 mg and should not use dextromethorphan for more than 7 days without consulting a healthcare provider. Additionally, individuals with certain medical conditions, such as COPD, or those taking MAO inhibitors should consult a healthcare provider before using dextromethorphan, as it may not be suitable for all cough types and can interact with certain medications.
Some key points to consider when using dextromethorphan include:
- Taking only as directed and not exceeding the recommended dosage
- Avoiding alcohol while using dextromethorphan
- Discontinuing use if cough persists beyond 7 days or is accompanied by fever, rash, or persistent headache
- Consulting a healthcare provider before using dextromethorphan if you have certain medical conditions or are taking MAO inhibitors
- Being aware of potential interactions with other medications and medical conditions.
It's also important to note that dextromethorphan works by acting on the cough center in the brain stem to reduce the cough reflex, and its effectiveness may vary depending on the individual and the underlying cause of the cough. As with any medication, it's essential to weigh the potential benefits and risks and to consult a healthcare provider if you have any concerns or questions. The study by Molassiotis et al. 1 provides the most recent and highest quality evidence for the recommended dosage of dextromethorphan, and its findings should be considered when making treatment decisions.
From the FDA Drug Label
Directions take every 4 hours or as directed by a doctor chew thoroughly before swallowing adults and children 12 years of age and over - 2 chewable tablets every 4 hours, not to exceed 12 chewable tablets in any 24-hour period The recommended adult dose of dextromethorphan for cough suppression is 2 chewable tablets every 4 hours, not to exceed 12 chewable tablets in any 24-hour period 2.
From the Research
Dextromethorphan Adult Dose
The recommended adult dose of dextromethorphan (DM) for cough suppression can vary based on the specific formulation and the condition being treated. Here are some key points regarding the adult dose of DM:
- A study from 1983 compared the efficacy of dextromethorphan and codeine in patients with chronic cough, using a dose of 20 mg for both preparations 3.
- A 2023 study investigated the use of dextromethorphan premedication for cough suppression during flexible bronchoscopy in adults, using a dose of 90 mg (30 ml of dextromethorphan syrup) 1 hour before the procedure 4.
- Another study from 2000 evaluated the antitussive efficacy of a single dose of 30 mg dextromethorphan in patients with cough associated with acute upper respiratory tract infection 5.
- A 2024 study examined the efficacy of a combination syrup containing bilastine, dextromethorphan (20 mg), and phenylephrine in patients with dry cough, with the syrup administered three times daily for 7 days 6.
Key Findings
Some key findings related to the adult dose of dextromethorphan include:
- Dextromethorphan at a dose of 20 mg was found to be effective in reducing cough frequency and intensity in patients with chronic cough 3.
- A dose of 90 mg (30 ml of dextromethorphan syrup) was used in a study investigating the use of dextromethorphan premedication for cough suppression during flexible bronchoscopy in adults 4.
- A single dose of 30 mg dextromethorphan was evaluated for antitussive efficacy in patients with cough associated with acute upper respiratory tract infection, but the results showed little difference between the treatment and placebo groups 5.
- A combination syrup containing bilastine, dextromethorphan (20 mg), and phenylephrine was found to be efficacious and safe in the treatment of acute dry cough due to a common cold or allergy 6.