Description: Dextromethorphan 10mg is used for treating chronic cough and bronchitis. DMH is a synthetic opioid that works by binding to specific receptors in the brainstem. Phenylephrine Hcl relaxes blood vessels and decreases swelling in the mucous membranes. PHE is often combined with pseudoephedrine hydrochloride (PSE). CPM treats allergic reactions like hay fever, asthma, and food allergies. CPM also helps prevent nausea and vomiting associated with pregnancy.