ZZZQUIL NIGHTTIME SLEEP-AID (DIPHENHYDRAMINE HYDROCHLORIDE) LIQUID [THE PROCTER & GAMBLE MANUFACTURING COMPANY] a breathing problem such as emphysema or chronic bronchitis glaucoma difficulty in urination due to enlargement of the prostate gland sleeplessness persists continuously for more than 2 weeks. Insomnia may be a symptom of serious underlying medical illness.