Of the non-prescription medications, it is the antihistamines that are most often marketed as sleep drugs, due to their sedative effects.1 As non-prescription agents, they are relatively inexpensive, but there is no systematic evidence for their efficacy as hypnotics.1,2 Furthermore, there are significant concerns over their safety profiles, which may include residual daytime sedation, diminished cognitive function, delirium (a particular concern in the elderly), dry mouth, blurred vision, constipation, and other anticholinergic side effects.1,2
References:
1. Reeder CE, Franklin M, Bramley TJ. Current landscape of insomnia in managed care. Am J Manag Care 2007; 13: S112–S116.
2. National Institute of Health. NIH State of the Science Conference statement on manifestations and management of chronic insomnia in adults statement. J Clin Sleep Med 2005; 1 (4): 412–421.