Key takeaways
Dayquil (acetaminophen/dextromethorphan/phenylephrine) and phenylephrine (Sudafed PE) are both used to relieve symptoms of the common cold, such as nasal congestion. Dayquil is a combination medication that includes an analgesic, a cough suppressant, and a decongestant, making it suitable for treating a wider range of cold and flu symptoms, such as cough, sore throat, and fever. In contrast, phenylephrine is a single-ingredient decongestant that specifically targets nasal and sinus congestion. Both medications are available over the counter, and may cause side effects such as insomnia and agitation. Both medications can interact with monoamine oxidase inhibitors (MAOIs) and should not be taken together or with other medications containing similar ingredients to avoid overdose.
