Table 2. Participants’ behavior regarding the use of medications that contain diphenhydramine hydrochloride (n = 361)*.

*Fifty-three respondents had no previous history of use of medications that contain diphenhydramine hydrochloride; they were excluded from the analysis.

†Variable with multiple response answers.

Characteristics	N (%)
On a daily basis, how frequently do you use over-the-counter sleep medications that contain diphenhydramine hydrochloride?
Once per day	231 (31.9%)
Twice per day	9 (2.5%)
Thrice per day	1 (0.30%)
One to two times per week	6 (01.7%)
One to two times per month	14 (03.9%)
Rarely	55 (15.2%)
As needed	45 (12.5%)
On a monthly basis, how frequently do you use over-the-counter sleep medications that contain diphenhydramine hydrochloride?
Once per month	116 (32.1%)
Twice per month	44 (12.2%)
Thrice per month	45 (12.5%)
More than five times per month	8 (2.2%)
A couple of times per week	97 (26.9%)
Rarely	30 (8.3%)
As needed	21 (5.8%)
How many pills do you take at a time
One pill	242 (67%)
Two pills	110 (30.5%)
Three pills	2 (0.60%)
Other	7 (1.9%)
Side effect of sleep medications†
Dizziness or imbalance	101 (28%)
Dryness of the mouth, nose, or throat	71 (19.7%)
Anxiety, nervousness, or hyperactivity	64 (17.7%)
Palpitations	60 (16.6%)
Constipation or diarrhea	39 (10.8%)
Abdominal pain	34 (09.4%)
Muscle weakness	31 (08.6%)
Visual disturbances	27 (07.5%)
Nausea or vomiting	25 (06.9%)
Skin irritation	9 (2.5%)
Difficulty or painful urination	7 (1.9%)
Others	3 (0.80%)