Diphenhydramine does not reduce the incidence of nighttime awakening

Many clinicians treat sleep problems with diphenhydramine, but the effectiveness of this antihistamine in infants who awaken frequently during the night has not been studied. Investigators therefore designed a trial to determine the effects of diphenhydramine on infant sleep during one week of treatment and at two and four weeks after treatment was discontinued. The trial was conducted in 22 infants between 6 and 15 months old who slept in a crib and awoke two or more times a night and in the same number of controls.

After a seven-day observation period, parents gave their infant diphenhydramine (1 mg/kg of body weight) or placebo 30 minutes before bedtime. After the treatment week, parents were asked whether the treatment improved the number of night awakenings that required their intervention. Parents also tracked their child's sleep for the first 28 nights with a diary and recorded their satisfaction with his (her) sleep on four occasions during the trial.

During one week of therapy and at follow-up two and four weeks later, diphenhydramine was no more effective than placebo in reducing nighttime awakening or in improving overall parental satisfaction with infants' sleep. Only one of the 22 children who received diphenhydramine showed improvement, compared with three of 22 who were given placebo (Merenstein D et al: Arch Pediatr Adolesc Med 2006;160:707).