A Study to Evaluate the Safety of Combination Montelukast/Loratadine in Mexican Participants With Allergic Rhinitis (MK-0476A-484)

Inclusion Criteria:

• Not pregnant or breastfeeding and does not plan to become pregnant during the studyand the 14-day follow-up period

• Female participants of reproductive potential agree to remain abstinent or use oneacceptable method of birth control at least 14 days prior to signing the informedconsent until 14 days following the last visit

• History for at least 2 years of seasonal allergic rhinitis symptoms that are knownto flare during the local allergy season or a clinical history of at least 2 yearsof perennial allergic rhinitis symptoms that persist year round

• For participants with seasonal allergic rhinitis: a positive skin-prick test (wheal >= 3 mm greater than saline control) to one of the allergens active during the localallergy season or a positive radioallergosorbent test (RAST [defined as a score >=Class III])

• For participants with perennial allergic rhinitis: a positive skin test (wheal >=3mm greater than saline control) to one of the relevant perennial allergens or apositive RAST (defined as a score >= Class III)

• Nonsmoker and has been a nonsmoker for at least 1 year prior to study Visit 1 with asmoking history of no more than 10 pack-years (1 pack [20 cigarettes] per day for 10years)

• Must be in good and stable physical health and mental health

Exclusion Criteria:

• Hospitalization or hospitalization within 4 weeks of the first scheduled study visit

• Pregnancy or within <= 8 weeks postpartum or is breast feeding

• Any major surgical procedure within 4 weeks of the first scheduled study vist

• Current or recent past abuser of alcohol or illicit drugs

• Prior participation in a clinical trial of montelukast or loratadine within the 4weeks prior to the first scheduled study visit

• Requires treatment other than inhaled short-acting β-agonist for asthma

(e.g., inhaled or oral corticosteroid, theophylline, nedocromil, cromolyn, oral orlong-acting inhaled β-agonist, leukotriene receptor antagonist, leukotrienesynthesis inhibitor) and/or uses more than 8 puffs per day of inhaled short-acting β-agonist

• Presence of an upper respiratory tract infection (URI), sinusitis, infectiousrhinitis (with symptoms such as sore throat, fever, thick purulent rhinorrhea),ocular infection, or history of any of these within 4 weeks prior to the firstscheduled study visit or any time between study Visits 1 and 2

• Other than asthma, any active, acute, or chronic pulmonary disorder which isdocumented by history or physical examination

• Rhinitis medicamentosa, or non-allergic rhinitis

• Recent history (within 3 months prior to the first scheduled study visit) of aclinically significant psychiatric disorder

• History of an anaphylactic reaction to or is otherwise hypersensitive to

montelukast, loratadine, or one of their components

• History or current evidence of any general medical condition, concomitant therapy,lab abnormality or other circumstance that might confound the results of the studyor interfere with the patient's participation for the full duration of the study

• History of illness that would require treatment with an excluded medication, couldbe immediately life threatening (ventricular arrhythmia, diabetes mellitus that isnot well controlled), would pose restriction on participation or successfulcompletion of the study, or would pose additional risk to the patient byadministering the study drug

• History of malignancy ≤5 years prior to signing informed consent, except foradequately treated basal cell or squamous cell skin cancer or in situ cervicalcancer