Dextromethorphan (Delsym) does not generally cause or worsen high blood pressure. In addition, there are no drug interactions between dextromethorphan, amlodipine, and metoprolol.
However, be wary of combination ingredient cold and cough products that contain dextromethorphan, as it is a common component in many multi-ingredient formulas. Products containing phenylephrine or pseudoephedrine may increase blood pressure and should generally be avoided in patients with high blood pressure.
What Is Dextromethorphan?
Dextromethorphan (commonly referred to as DM on many over-the-counter products) is a cough suppressant that reduces the urge to cough. It is best to prevent bothersome dry cough or a cough that doesn’t involve mucus from the lower respiratory system.
Dextromethorphan should not be used to treat chronic cough, including cough related to asthma or COPD. If the cough lasts for more than one week or is associated with more severe symptoms such as nausea, vomiting, and fever, it is recommended to see a physician.
OTC Cough Expectorant - Guaifenesin
Another product that works against cough is Guaifenesin (Mucinex). Guaifenesin is a cough expectorant that helps break down mucus in upper and lower airway. Guaifenesin loosens phlegm and secretions which can then be expelled. Guaifenesin is best used to reduce the symptoms of having a deep cough that can’t be cleared.
Although many products contain both dextromethorphan and guaifenesin, it may be best to pick the single ingredient that will help based on the type of cough that you have. Taking several medications when one may be sufficient could lead to unnecessary side effects or risks.
All in all, dextromethorphan is unlikely to cause an increase in high blood pressure and does not have any drug interactions with amlodipine or metoprolol. Always be careful to read all active ingredients when selecting OTC products, as products with phenylephrine or pseudoephedrine may cause an increase in blood pressure.