What is the effect of Diphenhydramine (Benadryl) on sleep quality and architecture?

From the Guidelines

Benadryl (diphenhydramine) is not recommended for treating sleep onset or sleep maintenance insomnia due to its lack of improvement in sleep quality and potential for significant side effects. According to the American Academy of Sleep Medicine clinical practice guideline 1, diphenhydramine may reduce sleep latency by 8 minutes and increase total sleep time by 12 minutes, but it does not improve the quality of sleep.

Key Findings

• The study found that diphenhydramine has a mean reduction in sleep latency of 8 minutes compared to placebo, with a 95% CI of 2 minutes increase to 17 minutes reduction 1.
• Total sleep time was improved by a mean of 12 minutes longer compared to placebo, with a 95% CI of 13 minutes reduction to 38 minutes improvement 1.
• However, there was no improvement in quality of sleep compared to placebo, which is a critical factor in determining the effectiveness of a sleep aid 1.

Clinical Implications

The lack of improvement in sleep quality, combined with the potential for side effects, makes diphenhydramine a less desirable option for treating insomnia. As noted in the guideline, the recommendation is based on trials of 50 mg doses of diphenhydramine 1.

Alternative Approaches

Non-medication approaches, such as consistent sleep schedules, limiting screen time before bed, and creating a comfortable sleep environment, are preferable first-line treatments for insomnia. If medication is needed, discussing prescription options specifically designed for sleep with a healthcare provider would be more appropriate than using Benadryl long-term.

From the FDA Drug Label

Warnings Do not use • to make a child sleepy ... When using this product • marked drowsiness may occur The effect of Diphenhydramine (Benadryl) on sleep quality and architecture is that it can cause marked drowsiness.

• It is not recommended to use diphenhydramine to make a child sleepy.
• Alcohol, sedatives, and tranquilizers may increase drowsiness when taking diphenhydramine 2

From the Research

Effect of Diphenhydramine on Sleep Quality and Architecture

• Diphenhydramine, also known as Benadryl, is an over-the-counter antihistamine that is commonly used to treat insomnia and other sleep disorders 3, 4, 5.
• Studies have shown that diphenhydramine can improve sleep quality and architecture, including increased sleep efficiency and total sleep time 3, 4.
• However, the effects of diphenhydramine on sleep architecture are not well understood, and some studies have found that it can disrupt the normal sleep-wake cycle and reduce the amount of deep sleep and rapid eye movement (REM) sleep 3, 4.
• A study published in 2005 found that diphenhydramine produced significantly greater increases in sleep efficiency and a trend for increased total sleep time relative to placebo during the first 14 days of treatment 3.
• Another study published in 2015 found that diphenhydramine increased sleep quantity in pediatric burn patients, but did not result in a statistical improvement in sleep quality 4.
• A systematic review of over-the-counter agents for the treatment of occasional disturbed sleep or transient insomnia found that diphenhydramine had limited beneficial effects on sleep measures, specifically sleep onset and sleep quality, with favorable tolerability 5.

Comparison with Other Sleep Aids

• Diphenhydramine has been compared to other sleep aids, such as valerian and melatonin, in terms of its efficacy and safety 3, 5.
• A study published in 2005 found that valerian produced slightly greater, though nonsignificant, reductions of sleep latency relative to placebo and diphenhydramine at the end of 14 days of treatment 3.
• A systematic review published in 2015 found that melatonin, especially prolonged-release formulations in older individuals with diagnosed insomnia, demonstrated the most consistent beneficial effects on sleep measures, specifically sleep onset and sleep quality, with favorable tolerability 5.

Safety and Tolerability

• Diphenhydramine is generally considered safe and well-tolerated, but it can cause side effects such as drowsiness, dizziness, and dry mouth 3, 4, 5.
• A study published in 2005 found that there were no significant residual effects and no serious adverse events with diphenhydramine, and no rebound insomnia following its discontinuation 3.
• A systematic review published in 2015 found that diphenhydramine had favorable tolerability, but noted that the clinical trial data for diphenhydramine suggested limited beneficial effects on sleep measures 5.