Mary Warner
According to CDC, 8.4% of adults took sleep medication either every day or most days to help them fall or stay asleep in 2020. Women (10.2%) were more likely than men (6.6%) to take medication for sleep, and the use of sleep medication generally rose with increasing age.
Insomnia can be caused by stress and by both prescription and nonprescription medications, including antidepressants, antihypertensive agents, and decongestants such as pseudoephedrine and phenylephrine. Drinking caffeinated beverages in the late afternoon or evening hours can also cause insomnia, as can late-night exercise and late-evening meals.
Sleep specialists often suggest that patients practice sleep hygiene, such as daily sleep routines and environmental adjustments (e.g., dim light and cool temperatures) before beginning to use a sleep aid. The Sleep Foundation recommends following a consistent nightly routine, having a fixed wake-up time, prioritizing sleep, and avoiding naps during the day to catch up on sleep. Unplugging electronics and avoiding caffeine within a few hours of bedtime can also improve sleep.
For patients who have trouble falling or staying asleep, nonprescription sleep aids can be an effective solution. OTC sleep aids commonly include one of two antihistamines, diphenhydramine or doxylamine, to treat insomnia. Natural supplements, most often melatonin or valerian (Valeriana officinalis), are also available as sleep aids, though their efficacy is questioned.
Antihistamine sleep aids
Both diphenhydramine and doxylamine affect sleep by competitively blocking histamine-1 receptors and are well absorbed, typically taking effect within an hour after a dose. The usual dosage for patients 12 years and older is 50 mg diphenhydramine or 25 mg doxylamine, taken 30 minutes prior to bedtime.
Diphenhydramine is available as tablets, rapidly dissolving tablets, capsules, and liquid, while doxylamine is available only as tablets. Doxylamine has similar efficacy as diphenhydramine, but it has a longer half-life and may have residual effects. Adverse effects to both medications are those associated with antihistamine use, including dry mouth, nose, and throat; dizziness; nausea and vomiting; and constipation.
Combination products containing diphenhydramine plus acetaminophen, ibuprofen, or aspirin are also widely available. These are most often labeled with “PM,” such as Tylenol PM, Advil PM, or Excedrin PM, and contain 25 mg or 50 mg of diphenhydramine along with the analgesic medication.
Natural supplements
Complementary therapies such as melatonin, valerian, and chamomile (Matricaria recutita) are often promoted as sleep aids. The American Academy of Sleep Medicine clinical guideline, published in 2017, recommends against the use of melatonin or valerian for treatment of insomnia in adults based on insufficient evidence of their efficacy.
The recommendation against melatonin is based on 2 mg doses, which reduced sleep onset by an average of 9 minutes versus placebo but with only small improvements in sleep quality. Melatonin is likely most useful in shifting circadian rhythm.
Clinical trials using valerian and chamomile also show no statistically significant differences with placebo for sleep onset, duration, or efficiency according to a meta-analysis by Leach and Page published in the December 2015 issue of Sleep Medicine Reviews. Adverse events, including diarrhea, were more common when valerian was used versus placebo.
What to tell your patients
Advise patients to practice good sleep hygiene before trying OTC sleeping aids, including avoiding caffeine for several hours before bed. Ensure that patients understand that diphenhydramine and doxylamine both lose their effectiveness over time, with their sedative effect noticeably decreasing within days of repeated use. Patients with chronic insomnia should visit a physician specializing in sleep disorders to explore causes and potential treatment.
For further information, please see Chapter 46 of APhA’s Handbook of Nonprescription Drugs, available in print via the bookstore on pharmacist.com or online through Pharmacy Library. ■