Key takeaways
Diphenhydramine (Benadryl) and dextromethorphan (Delsym) are both over-the-counter medications used to treat symptoms related to the common cold. However, they belong to different medication classes and have different uses. Diphenhydramine is an antihistamine that helps relieve allergy symptoms, cold symptoms, and can be used as an occasional sleep aid due to its sedative effects. In contrast, dextromethorphan is a cough suppressant that can help with a dry cough. Diphenhydramine is available in various forms, such as tablets, capsules, and liquids, and is typically taken every 4 to 6 hours. Dextromethorphan comes in extended-release (taken every 12 hours) and immediate-release (taken every 6 to 8 hours) forms. While diphenhydramine can cause drowsiness, dizziness, and dry mouth, dextromethorphan may lead to nausea and, less commonly, drowsiness. It's important to avoid alcohol with both medications, as it can increase drowsiness. Additionally, dextromethorphan can interact with certain medications, like antidepressants, leading to a serious condition called serotonin syndrome.
