Which of the following is a common drug associated with antitussives?

Dextromethorphan is recognized as a common drug associated with antitussives due to its effectiveness in suppressing the cough reflex. It acts on the central nervous system, specifically targeting the cough center in the brain to reduce the urge to cough. This makes it particularly useful in treating coughs that are non-productive, allowing for relief from interventions that can be irritating or disruptive without addressing underlying issues.

In the context of cough treatment, other listed options serve very different purposes. Aluminum hydroxide is primarily used as an antacid, managing conditions like heartburn and indigestion. Guaifenesin, while effective as an expectorant to help relieve chest congestion, does not suppress the cough reflex. Omeprazole is a proton pump inhibitor used to treat gastroesophageal reflux disease (GERD) and related conditions and does not play a role in cough management. Thus, dextromethorphan stands out as the appropriate choice regarding antitussives.