This is a single-group, single-center, open-label, one period, bioavailability study. This study will evaluate the pharmacokinetic (PK) profile of chlorpheniramine in a population of children aged 2 to <12 yrs and adolescents aged 12 to <18 yrs. Twelve blood samples (3.0 mL) for chlorpheniramine analysis will be drawn at time 0 (pre-dose), and at 0.5, 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 hours after dosing. Plasma levels of chlorpheniramine will be determined. The following primary, single-dose PK parameters for chlorpheniramine will be determined using noncompartmental methods: AUCL, AUCI, and Cmax. The following PK parameters will also be determined to provide a complete profile of the drug, as appropriate: oral clearance (CL) and volume of distribution (Vd) and adjusted for body weight (per kg); time to reach Cmax (tmax), and apparent elimination constant (Kel) and half-life (t1/2). The PK parameters will be summarized using descriptive statistics.