Loratadine/Montelukast Sodium

The purpose of this study is to assess the safety and tolerability of montelukast 10 mg/loratadine 10 mg versus placebo in Mexican participants with allergic rhinitis.

This is study of LMC, phenylephrine, and placebo in subjects with SAR. There are three visits: At Visit 1, subjects will be evaluated for participation and, if they qualify, will attend Visit 2 for priming. At Visit 2, ragweed pollen will be fed continuously and dispensed into the environmental exposure unit to induce an allergic reaction. Pollen counts will be monitored and recorded. During the priming visit(s), subjects will be evaluated to determine if they qualify. If qualified, they will return for Visit 3, where ragweed pollen will be fed continuously and dispensed into the environmental exposure unit to induce an allergic reaction. Pollen counts will be monitored and recorded as in the Priming Session. Subjects will complete symptom evaluations and if qualified, they will receive study medication and remain in the environmental exposure unit where symptoms will be evaluated for 8 hours after dosing. PNIF will be evaluated only during the treatment session. Four nasal symptoms (rhinorrhea, nasal congestion, sneezing, and nasal itching) and three non-nasal symptoms (itching/burning eyes, tearing/watery eyes, and itching of ears/palate) will be evaluated. Adverse events will be collected throughout the study to assess safety and tolerability, and vital signs will be collected at Visit 1 and at the end of Visit 3.