e., with antihistamine chlorpheniramine 4
mg, decongestant phenylephrine 12.5
mg, and cough suppressant dextromethorphan 15 mg, each per 5 mL), then the guideline dose for a 4-year-old is one-quarter teaspoon (the one-half teaspoon dose is for age 6-11 years, while the full teaspoon dose is for ages 12 years and up).