Dextromethorphan HBR Active Ingredient
Dextromethorphan hydrobromide (HBr) is the active ingredient in dextromethorphan HBR products, which functions as a cough suppressant by acting on the central cough mechanism in the brain. 1
Composition and Formulation
Dextromethorphan HBR products contain:
- The active ingredient dextromethorphan hydrobromide
- In extended-release formulations (like Delsym), the active ingredient is dextromethorphan polistirex, which is equivalent to dextromethorphan hydrobromide 1
The hydrobromide (HBr) portion refers to the salt form of dextromethorphan, which improves its solubility and bioavailability compared to the free base form.
Mechanism of Action
Dextromethorphan works by:
- Acting on the central cough mechanism in the brain 2
- Functioning as an N-methyl-D-aspartate (NMDA) receptor antagonist 3
- Providing cough suppression without the typical opioid effects (despite being semi-synthetic opioid in structure) 4, 5
Clinical Use
Dextromethorphan is indicated for:
- Dry, non-productive cough that is bothersome and disruptive
- Symptomatic relief, especially for nighttime cough that interferes with rest
- Typical dosing of 10-15 mg three to four times daily 2
Important Considerations
- Dextromethorphan has limited efficacy (less than 20% suppression of cough due to upper respiratory infection) 2
- It should be avoided when patients are coughing up significant amounts of sputum or when cough serves a physiological purpose to clear mucus 2
- Extended-release formulations (polistirex) have a duration of action 2-3 times longer than standard formulations 6
- Some formulations may contain additional ingredients like sodium metabisulfite, which can cause allergic-type reactions in sensitive individuals 1
Potential for Misuse
It's important to note that dextromethorphan can be misused:
- At high doses, it can produce intoxicating and psychedelic effects 3
- Long-term users may develop tolerance, requiring increased doses to achieve the same effects 4
- Overdose can lead to serious adverse effects, particularly in children 6
Dextromethorphan hydrobromide is the primary active ingredient that provides the therapeutic cough suppression effect in these medications, with various formulations using different delivery systems to modify its release and duration of action.