From the Guidelines
Dextromethorphan does not help as a decongestant for nasal congestion. It is primarily a cough suppressant that works by affecting signals in the brain that trigger the cough reflex. For nasal congestion, medications containing pseudoephedrine, phenylephrine, or oxymetazoline are more appropriate as they work by constricting blood vessels in the nasal passages, which reduces swelling and mucus production 1.
Key Points to Consider
- Dextromethorphan acts on the central nervous system to suppress the cough center in the brain, rather than affecting the nasal passages directly.
- Oral decongestants, such as pseudoephedrine and phenylephrine, are effective at relieving nasal congestion in patients with allergic and nonallergic rhinitis, but can result in side effects such as insomnia, loss of appetite, irritability, and palpitations 1.
- If you're experiencing both cough and nasal congestion, you might need to use a combination product that contains both a cough suppressant like dextromethorphan and a separate decongestant ingredient, or use two different medications.
- Many over-the-counter cold and flu products contain multiple active ingredients to address different symptoms.
- The efficacy and safety of oral decongestants, especially in certain populations like children under 6 years old, should be carefully considered due to potential risks of agitated psychosis, ataxia, hallucinations, and even death 1.
From the Research
Dextromethorphan as a Decongestant
- Dextromethorphan is primarily used as a cough suppressant, but its effectiveness as a decongestant for nasal congestion is not well-established 2, 3, 4, 5.
- The study 2 focuses on the efficacy of a combination syrup containing bilastine, dextromethorphan, and phenylephrine in treating cough associated with the common cold or allergy, but it does not specifically address dextromethorphan's role as a decongestant.
- Another study 3 reviews the efficacy of nasal decongestants in reducing nasal congestion in adults and children with the common cold, but it does not mention dextromethorphan as a decongestant.
- A review of decongestants 4 discusses the therapeutic actions of antihistamines and decongestants, but it does not include dextromethorphan in the list of common decongestants.
- Dextromethorphan is reviewed as an N-methyl-d-aspartate receptor antagonist in the management of pain 5, but this study does not address its potential use as a decongestant.
Decongestant Properties
- Phenylephrine, a common decongestant, is often used in combination with dextromethorphan in cough and cold medications 2.
- The effectiveness of phenylephrine as a decongestant is subject to first-pass metabolism, which may limit its bioavailability 4.
- Pseudoephedrine and phenylpropanolamine are also common decongestants, but their efficacy and safety profiles differ from phenylephrine 4.