Final answer:
For cases of severe cough, dextromethorphan is a commonly used centrally acting antitussive. The effectiveness of cough suppressants, like dextromethorphan, is more evident in adults than in children, where use is discouraged due to lack of evidence and possible risks.
Step-by-step explanation:
Centrally acting antitussives like dextromethorphan are used in cases of severe cough. Among the options provided, dextromethorphan is recognized for its cough suppressant properties. It is an ingredient found in many over-the-counter cold and cough medications. These medications, particularly dextromethorphan, may be more effective in decreasing cough in adults with viral upper respiratory infections but are not recommended for children due to a lack of evidence of effectiveness and potential harm. Contrastingly, pseudoephedrine acts as a decongestant rather than as a cough suppressant. Loratadine is an antihistamine designed for allergy management, and acetaminophen is an analgesic and antipyretic, not specifically targeting cough suppression.