• Change from baseline in the subject's mean reflective nasal congestion/stuffiness symptom score [ Time Frame: every 12-hours over the 14-day treatment period ] [ Designated as safety issue: No ]
  

• Change from baseline in the subject's mean reflective Total Nasal Symptom (TNS) Score [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Change from baseline in the subject's mean instantaneous TNS Score [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Change from baseline in the subject's mean reflective Total SAR Symptom (TSS) Score [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Change from baseline in the subject's mean instantaneous TSS Score [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Change from baseline in the subject's mean reflective score for each of the seven remaining individual SAR symptoms, excluding nasal congestion/stuffiness [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Change from baseline in the subject's mean instantaneous score for each of the eight individual SAR symptoms [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Onset of action for diphenhydramine treatment for nasal congestion/stuffiness was determined by comparing the change from baseline in the subject's instantaneous nasal congestion/stuffiness scores for diphenhydramine versus placebo [ Time Frame: taken at 15, 30, 60 and 90 minutes after the initial dose. Baseline was the score taken just prior to the initial dose. ] [ Designated as safety issue: No ]
  
• Onset of action for diphenhydramine treatment for allergic rhinitis symptoms was determined by comparing the change from baseline in the subject's instantaneous TNS scores for diphenhydramine versus placebo [ Time Frame: taken at 15, 30, 60 and 90 minutes after the initial dose. Baseline was the score taken just prior to the initial dose ] [ Designated as safety issue: No ]
  
• Duration of action for diphenhydramine for treatment of nasal congestion/stuffiness was evaluated by comparing the change from baseline in the subject's mean instantaneous nasal congestion/stuffiness scores for diphenhydramine versus placebo [ Time Frame: taken at the six-hour trough (just prior to the 8:00 pm dose) and the 12-hour trough (just prior to the 8:00 am dose) ] [ Designated as safety issue: No ]
  
• Duration of action for diphenhydramine for treatment of allergic rhinitis symptoms was evaluated by comparing the change from baseline in the subject's mean instantaneous TNS scores for diphenhydramine versus placebo [ Time Frame: taken at the six-hour trough (just prior to the 8:00 pm dose) and the 12-hour trough (just prior to the 8:00 am dose) ] [ Designated as safety issue: No ]
  
• Time to maximal effect was assessed by a by-day analysis of the primary efficacy endpoint and select secondary endpoints [ Time Frame: 14 Days ] [ Designated as safety issue: No ]
  
• Subject's global evaluation of response to treatment [ Time Frame: at Visits 3 and 4, analyzed separately at each visit ] [ Designated as safety issue: No ]
  
• Change from baseline in the Investigator's TNS score [ Time Frame: at Visits 3 and 4, analyzed separately for each visit. Baseline was the score at Visit 1 ] [ Designated as safety issue: No ]
  
• Change from baseline in the Investigator's TSS score [ Time Frame: at Visits 3 and 4, analyzed separately for each visit. Baseline was the score at Visit 1 ] [ Designated as safety issue: No ]
  
• Change from baseline for each of the eight individual Investigator's SAR symptoms [ Time Frame: at Visits 3 and 4, analyzed separately for each visit. Baseline was the score at Visit 1 ] [ Designated as safety issue: No ]
  
• Investigator's global evaluation of the subject's response to treatment [ Time Frame: at Visits 3 and 4, analyzed separately for each visit ] [ Designated as safety issue: No ]
  
• Number and percentage of subjects experiencing adverse events [ Time Frame: Duration of study ] [ Designated as safety issue: No ]
  
• Change from baseline and potentially clinically important vital signs (systolic and diastolic blood pressure, pulse, and respiratory rate) [ Time Frame: Duration of study ] [ Designated as safety issue: No ]
  
• Occurrence of somnolence [ Time Frame: Overall and weekly ] [ Designated as safety issue: No ]
  

Subjects who met the inclusion/exclusion criteria were enrolled into the placebo run-in phase of the study on Day -7 (prerandomization, Visit 1). Baseline symptom scores were established during this run-in phase.

Subjects with moderate nasal congestion who took at least 80% of their study medication during the run-in phase were eligible for enrollment in the two-week double-blind phase of the study and were randomized on Day 1 (randomization, Visit 2). They were treated for two weeks with their assigned medication. The severity of signs/symptoms were evaluated by the subjects every morning and night and by the investigator at each visit on Day 7 and Day 14.

In addition, the subject and investigator provided a global evaluation of response to treatment on Day 7 and Day 14. Safety was evaluated by adverse events reported during the study, vital signs, and the incidence of somnolence.